2 Stroke Engine Runs Better With Choke On

What does ‘Choke On’ mean? How do you know when a choke is On or Off? In the day of automatic chokes, a manual choke can be confusing. Just did two engines that had the same problem. I am sorry you are having a problem with the snow blower. This accounts for why many freshly assembled engines operate well during the break in period, but seize the first time the throttle is hung wide open. By going leaner and eliminating this, you will be out of adjustment when a load is put on the engine. Turn off the engine and remove the gas cap. 9 is 4500 - 5500. I pulled the choke, and it started right up. That's the throttle plate. 5 L B20 engines, we installed the 45 DCOE carbs that are usually on my racecar. As soon as I give it revs the choke automatically disengages & the engine stops straight away. A rare trimmer symptom is when it works, but only when the choke is on. There are a few set-ups not used on a normally aspirated engine that can make all the difference in how the engine runs. Compression stroke: The intake valve closes (the exhaust valve was already closed), and the upward motion of the piston compresses the fuel/air mixture from atmospheric pressure to approximately 150 psi (the fuel burns better when it is compressed, and the theoretical efficiency of an internal compression engine is linked to its compression. Finally make sure you have the choke lever down completely after the ATV is started and warmed up. If you own one of these, or other similar two-stroke engines, you are familiar with the process of starting one up - have the choke on full to begin with, then after it stops, switch it to half-choke and let it run until the engine is warm up. I have taken the muffler off & it was well choked up with coke but after cleaning it's still doing it. Small engines: Better to keep the choke lever on or off when unused? back off after one of my two week checkout runs. #1- Fire it up and keep it running at a low rpm-enough so it doesn’t stall for 5 minutes—DO NOT put it in gear or ride it, just let it run. I've had the carb off and cleaned it (though, oddly, I couldn't remove the main jet which is held up in place by a plug in the top of the float chamber. After running the Mikunis on one of our 2. Just be aware of this as a factor in performance. AMSOIL Synthetic 2-Stroke Injector Oil offers the convenience of one formula for the tough conditions of all two-stroke recreational equipment. Small two-stroke engine runs poor. For the 34-PICT/3 carburetor, the squirt volume should be 1. When you notice a Stumble, Back off the throttle a little 1/8-1/4: 1. Runs pretty good and putting out 123V with it on semi-choke. I took the carb out completely and ran compressed air through everything. 9 four stroke engine runs smooth with a rpm loss, IT"S the cdi gone BAD. A: Gas-powered blowers use a cord to start. Kick-starting an old motorcycle is part of the classic motorcycle culture. With less air, there is more fuel. The modified 2-stroke engine for LH2 injection on board. However, you start it up on choke and everything is fine until you turn the choke off, and the engine dies. Manual start 1994 Manual choke integral tank Has the facility to run an external tank Short shaft 360 engine Forward and neutral only Great condition for year Water cooled starts runs and pumps £300. Re: 1984 Ez-go 2 stroke No Power- need Help i think runs the same with the belt off, no power. Now slowly i anti clockwise i screwed-out the fuel screw, at 2-3 complete anticlockwise turn-out--the engine rpm is idle. I slowly pushed the choke in as the engine got warmer and got to 0% choke and the engine was running great, idling just fine. (1973 FJ40 stock carb ported base to run a 60 series dizzy) I take it my carb is running too lean and runs a bit richer when the choke is out a bit. In this post I'll explain the process of rejetting your carburetors in 3 simple steps: Main adjustment (main jets) Fine adjustment (gas needle + air adjustment) Stationary adjustment (air screw / fuel screw) Before you start. It does not appear to be the choke, the engine has not had time to completely warm up when it dies and the choke is still fully. Old Toros with the 2-cycle Suzuki engines. In this post I’ll explain the process of rejetting your carburetors in 3 simple steps: Main adjustment (main jets) Fine adjustment (gas needle + air adjustment) Stationary adjustment (air screw / fuel screw) Before you start. The piston diameter for both the 9. This happens for all broad topic articles; this is why so many vital articles are so awful. This synthetic fuel additive works in your power equipment with 2-cycle and 4-cycle engines. Anyhow, it fired right up and is running like a top. Choke operation on yamaha 90 hp 2 stroke if it's sat a long time without being run. I have a 40 hp evinrude that after a couple 3 attempts to get running properly I am at a loss. -Mike it closes slowly as the engine warms up. For peak power, most engines like an air/fuel ratio of 12. A vacuum gauge can tell you a lot about an engine's condition, similar to a full leak down test - but in a much easier way. All these things are typically done in automotive applications to compensate for the limitations of the carburetor. Because 2-stroke engines are designed to run at a higher RPM, they also tend to wear out faster; a 4-stroke engine is generally more durable. Why Does my Small Engine Run Better with the Choke on? Unfortunately, we hear this question asked more often than ever before. Throttle cable has stretched. Engine started on about 5th pu. It's an important mechanism that helps your engine run smoothly by ensuring that the optimal ratio of fuel/air enters the engine. electric-start engines, simply turn the key – and you’re up and running. However your engine does not have a choke. 9 is 4500 - 5500. there is still some passage inside the carb blocked not letting enough fuel into the cyl. putting a tablespoon of gas in the throat of carburetor, engine starts immediately and runs 2-3 seconds until tablespoon of gas is consumed. any time you need the choke on for the engine to run you are shutting down the air flow because there is not enough fuel getting to the cyl. Start motor and run it on the stand. Also some of the 2 stroke carbs you can turn the choke to adjust the idle. I turned off the choke and checked if the throttle was stuck none of those things seemed to effect the engine. What could be causing my lawn mower to surge? Once the engine is warm, does it run better? From the video, it seems that the choke just has to stay closed longer. As soon as I give it revs the choke automatically disengages & the engine stops straight away. Since you just got the engine done I would double check the carburetor. (Lil 2 stroke took a dump RIP it idles fine but when i want to rev the engine it just feels like. ZENOAH G260RC Car/Buggy Engine. I hope that I can ask this question about a CR500 - as basically the issue at hand is really targeted at the carb which is a Keihin - as used on a CR250 and a CR500. In two stroke engines—discussed elsewhere—ports in the cylinder liner that are alternately covered and uncovered by the piston are commonly used. Hard to diagnose a running problem via long-distance. Below is a chart of common Engine problems and some easy troubleshooting to fix the problem you may be experiencing. Once the engine starts, turn off the choke after a few seconds, the engine should rev and run something like, then adjust the tick-over screw to get a fast tick over for approximately 30 minutes to bed in a new engine. The sound of a four stroke engine is so sweet, and so much more realistic, that many of us will go to great lengths to try and install one in an RC plane. 2 stroke carbs are easy to clean. It is now commonplace on both four-stroke and two-stroke engines and is much more reliable and more efficient in today’s market. 0 hp Honda engine that only runs with the choke on - Answered by a verified Technician We use cookies to give you the best possible experience on our website. This is the most important step in jetting your carburetor--period! 1. Any help much appreciated. For the 34-PICT/3 carburetor, the squirt volume should be 1. The four-stroke premixed hydrogen engine still has the following problems: H2 injection cam FIG. Fuel can then be drawn into the engine by turning the propeller. Put the carb back on, and now it starts GREAT (1-3 pulls with choke) but WILL NOT IDLE or run without the choke full on?!?!?! If you have the choke full on, you can ride around with it and it screams, runs basically fine at full throttle. The motor starts right up either with the choke or at a fast idle (if warm). ­ I­f you read How Two-stroke Engines Work, you learned that one big difference between two-stroke and four-stroke engines is the amount of power the engine can produce. Since there are fewer moving parts in a 2-stroke engine, they can afford to be cheaper. The choke reduces the amount of air that goes into the carburator. #2- After 5 minutes of running shut it off for 10. The only engines I've ever run in really cold weather was a 25hp Evinrude tiller, and now this 05 Merc 50hp. Kick Start a few times, if it does not start, pull out the choke then kick again. Mariner - 4 Stroke Outboard Manual Start, Tiller Control ? Short/Long Shaft Option Engine boat United Kingdom. I havent had a lot of experience with the rover/suzuki engines, does it fire if you put a bit of fuel down the carb? With these I have found the easiest way to get the carby off without having dramas with the linkages is to take the two nuts that hold the air filter housing on, tighten them against each other on the studs sticking out and unscrew the carb mounting studs out of the block. Squeeze the clutch lever before shifting gears, just like operating a manual transmission in your car. When this happens the internal clearances of the engine open up and two-stroke engine loses compression. When you turn off the choke there is too much air and the engine dies. While you may have a different style carburetor on your machine, the remedies de-scribed here-in will work with most any type of carburetor. Does the engine run with the choke on or off?. Whether or not your carburetor is a MIKUNI or a KEIHIN, it does not matter. The carb, air cleaner, and exhaust pipe are all carefully tuned to work together. This engine only runs with choke in 1/2 position. As I'm sure you know. The engine turned over and even ran!. As soon as I give it revs the choke automatically disengages & the engine stops straight away. I'm running 20:1 cos i'm. There are. The 15 hp motor is rated at 5500 -7000 RPM according to a 1978 Johnson sales brochure. Now I don't have to run it with the choke slightly on. Carbon chokes off airflow, which causes the engine to slowly lose power and run poorly. Turn each screw clockwise two full turns. This'll coat the cylinder walls with more oil so the engine is easier to pull over. Immediately upon turning off the choke it dies. It runs great now, and accelerates better, and smoother. I use the Comma two stroke oil mixed at 40-1 , at about £2-70 a bottle enough for about 5 gallons of fuel. The choke lever opens and closes the choke valve in the carburetor. (Lil 2 stroke took a dump RIP it idles fine but when i want to rev the engine it just feels like. Are you up to the task of keeping multiple engines running smoothly? If you can get more than 30 of these 35 questions correct, you'll prove that you know your way around the two-stroke engine of your lawn equipment or the small four-stroke engine of your lawnmower. originally it was run without oil, piston lube as its oil injected, it trashed the piston. position for the engine to run. I didn't worry about this too much as I had lots of other work to do on the bike, but I had it running long enough to circulate the oil and coolant. Two-Stroke Fuel Ratios Pre-Mix Myth vs. better chance of making it back with this less sophisticated type of engine. It made starting very easy and I have used it ever since. I ended up buying a new 2 stroke Yamaha 6 and haven't had any problems since. The original recommended mix using standard oil of 40 years ago was 16:1 and in one case 12:1. What does 'Choke On' mean? How do you know when a choke is On or Off? In the day of automatic chokes, a manual choke can be confusing. Two possibilities, 1 Air leak-carb, head gasket, crankshaft seal. The Honda BF8 and BF9. In a four-stroke engine, it takes two revolutions to make the piston fire. DLA 32cc gas 2-stroke engine. Adjusting the carburetor on a 2 stroke engine This is generic advice but probably a good place to start. my 2 stroke blower only runs on idle or full choke. Runs pretty good and putting out 123V with it on semi-choke. The 2005 Zenoah 2 bolt G260RC engine is a 25. A: Gas-powered blowers use a cord to start. I don't know much about engines so maybe someone can offer me somewhere to check I have a snow blower that works just fine when the choke is on. This is the most common misconception about two stroke jetting: When a motor runs excessively hot and lacks power, it is on the verge of seizing. I do not have a similar mower, however many 4 cycle carbs have a very small passageway for air flow during idle. It made starting very easy and I have used it ever since. 4cc (34mm bore, 28mm stroke) performance machine. In order to start the engine the. It has always need a little choke to run smoothly after it warms up. I'm running 20:1 cos i'm. Just be aware of this as a factor in performance. So this system would be ineffective on a two-stroke engine if it was used upside down. Only runs with full choke. C) Motor revs clean and crisp but runs really hot and lacks power. Honda's GC and GS engines use the world's first small engine internal timing belt, designed to last the lifetime of the engine. When activated, the choke plate completely covers the venturi see this video of the choke plate to see it in action). A properly maintained engine runs better than one that is never serviced or only serviced occasionally. Choke operation on yamaha 90 hp 2 stroke if it's sat a long time without being run. By the symptoms you are having I suspect the problem is dirty passages in the carburetor. About to buy a riding lawnmower and was wondering between these two engines, which one would be the better option. The auto-choke is ON in it's natural state. I run two cars, a SBC and a Pontiac, both 350. One carb may fit several applications. Starts on full choke but will stall with choke fully open. Look at locomotive or steam boiler. No matter whether the carb adjustment screws are turned in fully and turned out as much as 8 turns, at about 9 turns they are out. com FREE DELIVERY possible on eligible purchases. Engine was stored in my garage, upright, from early November to this week. It's an introduction to small engines and covers many of the things that apply to 2-stroke engines (which will be covered on this page). In order to meet EPA standards, the Yamaha Banshee needed to be updated. I just purchased a brand-new, taiwanese 2009 Eton Beamer III 49cc 2-stroke scooter and have only ridden for 30 miles thus far. Turn the choke off and assess. WT363 viewed from engine side. 0 hp Honda engine that only runs with the choke on - Answered by a verified Technician We use cookies to give you the best possible experience on our website. I would say most of the damage I would see on 2 cycle engines was piston scoring from running too little or no oil in the fuel. And yes, these engines do meet the lower emissions standards and get better fuel mileage, which is a good thing. 9 is 4500 - 5500. Runs better as you climb to higher elevations ; Slight back-firing on deceleration. I tried to start it with and without manual choke and requires about 60 seconds of combined electric starter usage. Just be aware of this as a factor in performance. If the airflow through the airflow meter is disturbed, it can cause an engine stall with the clutch depressed. A two stroke running with neat petrol lasts about four minutes until it seizes up. At half choke it would run smooth but did not have full power. Carburetor Adjustment on 2-Stroke String Trimmers General Automotive. What is happening is that closing the choke plate restricts the airflow to provide an acceptable mixture based on the fuel that the idle circuit can provide. The standard 10. Place needle clip in mid-position. Do not use Engine oil with additives. No more than one pop with the choke on or you risk another fatal flood. I'm not a certified mechanic in the least. Also check your fuel filter, could be after running for a while it clogs up and wont let the engine suck too much fuel through it. Re: 88 Ezgo 2 cycle, no power good compression It doesn't run any better without the muffler on it as I just tried that. Start the trimmer and gently unscrew the gas cap halfway off. That’s because KOHLER Smart-Choke automatically adjusts the amount of fuel needed to start the engine. I've been reading a lot about DCR (dynamic compression ratio) to educate myself when discussing options with Cam selection. Fixing a wet plug (from a flooded engine) is easy. She got a new piston , bore and rings. When the engine is cold it needs rather more petrol, so the choke closes down the air inlet by a precise amount to compensate and enrich the mixture. If the choke is needed for warm engine re-starts, you have an engine or jetting problem. Starts on full choke but will stall with choke fully open. my 2007 brute force 650 runs a lot better with choke on. 2 Stroke Engine tuning is about getting all the core components working together in symmetry. This will set them in the "open" position. Now that you have cleared the engine of too much "liquid" gasoline and set the choke in the "on" position, pull the engine cord several times through until the engine "pops" one time. They only go together one way for the most part. The fat part connecting the two cables then goes behind the carburetors by the fuel line and connects to the bracket for it where the pull. It only does it on start up. It is hard to tell though with no load on it but i tried switching belts off of another running cart and there was no difference. Place needle clip in mid-position. Reality: Dirtbike : Rick Super Hunky Sieman demystifies two-stroke pre-mix ratios A properly jetted engine will run better, last longer and develop more. Use a hotter spark plug. Now this is of course providing your engine isn't blown up with a hole in the piston or something. Also, make sure that the choke isn't closed. Didnt help. Curing 2-cycle Engine Problems: Many 2-cycle engines have problems and are sent to the junk yard before their time. I have a 40 hp evinrude that after a couple 3 attempts to get running properly I am at a loss. Choke operation on yamaha 90 hp 2 stroke if it's sat a long time without being run. Disclaimer: Please understand that the content in this video is based on my own practical experience over the last. Hi my yamaha 25 6L2 runs with choke on but when i go to put my choke in the engine will run for about 10 secoundsthen start bogging out it sound to me that the was no fuel getting to the carbs but i Clymer Marine Maintenance and Repair Manual '99 '02 Yamaha 115 250 HP 2 stroke Outboards. If your Briggs & Stratton motor is missing, starting hard or won't start at all, correct. So this system would be ineffective on a two-stroke engine if it was used upside down. It is also cold, so it needs a very rich mixture to start. It definitely does not run well enough to mow, but I am unsure what else to try here. Headers can turn cherry red in extreme cases! Temporarily removing air filter element makes the engine run worse. It would be either a Briggs Platinum V-Twin or a Kohler 7000 series V-Twin. Anyhow, it fired right up and is running like a top. In 4-Stroke Engines, you do not mix oil with the gasoline. A carburetor has a lot of parts in it that consist of “soft” materials. ZENOAH G260RC Car/Buggy Engine. Because the surface of the parts is not that smooth, they need a time to run-in to have the parts get smooth and work together better. mercury 15hp two stroke starting problems The motor will start on choke and run when the choke is off ,it runs for 5 seconds and cuts out. I set each one to about 1/2 turn past the zero lash position. I have tried just pulling the choke & also tried pulling the choke & laying her sideways until a little gas runs out the overflow tube. However, if your scooter engine runs strong one moment and then feel sluggish the next, then it MIGHT be the auto choke sticking on. Thinking that perhaps something is clogged in the carburetor/jet, I. Now I don't have to run it with the choke slightly on. If the engine changes note or rpm you have found a leak. If it won't stay running go ahead and make it faster. 4-STROKE STARTING TIPS: With the four-stroke revolution bumping the rev limiter, more and more two-stroke fiends are entering the world of cams and valves and pumper carbs. Very popular 2-stroke carburetor. • The Pilot Jet in a 2 stroke version is screwed into a threaded hole at the base of the main body. If your lawn mower only runs with the choke on, check the carburetor. for the engine to run properly. Any dirt bike, whether it be a 2 stroke or 4 stroke, MUST have these 4 prerequisites to start and run:. If you need specific repair instructions related to your model, refer to the manual provided by the manufacturer. there is still some passage inside the carb blocked not letting enough fuel into the cyl. Anyhow, it fired right up and is running like a top. Sometimes you will run across an old two stroke engine that will only start with a squirt of starting fluid. Seals and all too but I'm pretty well betting that the crankcase seals are leaking air. Plug in a small heater or use a hairdryer pointed at the motor. When ever I work on any 2 cycle engine I go in this order: Check the piston the exhast for blockage. 2 out of 5 stars for Victa Corvette VGMS486 (400, 4 Stroke) in Petrol Lawn Mowers. This is a quality Taiwanese Denso DS 59mm big bore kit. The way you add oil differs whether you have a 4-stroke or 2-stroke engine. Keihin Carb Choke/Idle Truly you guys have a wealth of info. It would be either a Briggs Platinum V-Twin or a Kohler 7000 series V-Twin. I then tested the bike to get the coolant running through and to make sure I filled the oil to the right level. They are also more powerful than 4-cycle engines. pronounced that two-stroke engines and carburetors were the main violators and recommend switching to four-stroke engines and fuel-injection to help ATVs meet the mandated standards. Runs better at higher altitudes - AFR becomes normalized due to reduced atmospheric pressure allowing fuel into the venturi easier. It assumes that there are 2 adjusting screws - idle and high speed mixture. You might think that a pull starter, like on a Rokon, would be better than a kickstarter, but it's not about how you spin the engine, but about the fire triangle (fuel/air/spark). That fixed the problem. • Fill the tank with E-85/synthetic oil 40:1 mix – 3. In simple words, stroke is the distance of cylinder between piston moves. 9 4-Stroke Benefits:. 99% of 2 cycle motors are adjusted the same, no mater what brand they are. A: Gas-powered blowers use a cord to start. • A “flat” running engine or dull sound • Runs worse as engine warms Symptoms of a lean mixture are: • High cylinder head or exhaust temperature • Backfire/popping from the carburetor • Runs better with partial choke • Surging or cutting out • Pinging or rattling sound from engine under load The Pilot Jet, Idle Mixture Screw and. In my opinion and with my personal tests I can turn my fuel off run the bowl dry. This will set them in the "open" position. The motor is very difficult to cold start, even with moderate temperatures of 60 to 70 degrees. It also dies if you squeeze the trigger too quick. You don't indicate how the motor is running with the choke onsmooth or rough. just wanted to see if u can help. Powerful 2-Stroke Motor Back in the day, Husqvarna was famous for making some amazing 2-stroke motorcycles. Leaf blowers with two stroke engines are known to be more powerful when compared to their 4 stroke leaf blower engine counterparts. It then starts sputtering and dies and will not restart until I let it sit for awhile. Locate the two adjustment screws on the carburetor. Now back it out 1 1/2 turns. Runs pretty good and putting out 123V with it on semi-choke. So if a motor runs fine with the choke open, but doesn't run at all with the choke off, that usually means the air screw or idle screw are wrong. The first issue to address is jetting and carburettor tuning. When done right, they're cleaner, quieter, more efficient and more economical than a comparable two-stroke. Now I don't have to run it with the choke slightly on. Since you just got the engine done I would double check the carburetor. This'll coat the cylinder walls with more oil so the engine is easier to pull over. Starts on full choke but will stall with choke fully open. I have a new diaphram for the fuel pump but it does not seem like a fuel delivery issue. Just like full size IC engines there are 2-stroke and 4-stroke model airplane engines, also sometimes referred to as 2-cycle and 4-cycle. Locate the two adjustment screws on the carburetor. Honda portable outboards are compact, lightweight, and are ideal for sailboats, aluminum fishing boats, canoes, inflatables. 2 stroke idles all day but won't rev !! Two Stroke Engine Tech. Must jet your carb wide open, probablly better to get a big bell carb. Hi, I have a aprilia rs 50 2006 am6 motor. 5 L B20 engines, we installed the 45 DCOE carbs that are usually on my racecar. • Fill the tank with E-85/synthetic oil 40:1 mix – 3. 2 cycle engine will not run at full throttle with out choke 2/3s on, carb looks clean blew it out, no gunk, gas good, diaphrams look good, did not see dirt, jet non adjustible, (has a cap on it), is there a screen I cant see? engine run 4 times, off weed wacker, 31cc bolens. When ever I work on any 2 cycle engine I go in this order: Check the piston the exhast for blockage. A vacuum gauge can tell you a lot about an engine's condition, similar to a full leak down test - but in a much easier way. I am sorry you are having a problem with the snow blower. 1986 Ford F250 V8 Two Wheel Drive Automatic I switched from mechanical fuel pump to electric Airtex E8012S, 5-9 psi, 30gph, new fuel filter, connected to 10amp fuse. If this occurs, there are multiple parts to check, such as gas cap, carburetor, fuel filter, fuel lines, and gasket. I took the carb out completely and ran compressed air through everything. However your engine does not have a choke. Lean Symptoms. -Mike it closes slowly as the engine warms up. When building a Chrysler big block engines the target is “bigger is better” With all the after market parts made readily available today, we can custom design your crate engine to deliver extremely powerful street performance or off road track use. The other could be a clogged low speed and idle circuit. Two stroke motors are VERY touchy in the tuning process, if they run too rich, they bog down and quit. If you are running an 009 distributor, adjusting the accelerator pump to full stroke helps to minimize the flat spot that is inherent to this distributor (using a vacuum distributor is a better fix though). You need to push the choke down and turn the key with a slight touch of the gas pedal. The engine starts easily and runs strong for about a minute or two. String Trimmer only runs with choke on reset the needle and it was all better. If your Briggs & Stratton motor is missing, starting hard or won't start at all, correct. It also lacks power and after running for a while will stall. 2 out of 5 stars for Victa Corvette VGMS486 (400, 4 Stroke) in Petrol Lawn Mowers. What's better for the engine: leaving fuel in it or running it dry first? That's an important question. Plus it's a lot lighter. but I do know what I am doing when it comes to re-building and tuning small engines, mainly two strokes. Honda’s internal timing belt runs in oil, eliminating the need for conventional drive gears. Compression stroke: The intake valve closes (the exhaust valve was already closed), and the upward motion of the piston compresses the fuel/air mixture from atmospheric pressure to approximately 150 psi (the fuel burns better when it is compressed, and the theoretical efficiency of an internal compression engine is linked to its compression. 2000 50Hp Yamaha 2-Stroke Problems as well- is yours a 2 or 3 cylinder engine? unplugged a thermal censor and it would run much better not perfect but better. The 2 stroke carbs are controled by the air. 5in pitch alloy prop matched the 2. there is still some passage inside the carb blocked not letting enough fuel into the cyl. Now I'm getting the 4 cycling condition and then it kicks in the does the 2-stroke, so it's on and off. It sounds as though your choke may be stuck on or maladjusted. As I'm sure you know. One is near the engine. Engine starts and idles fine. I am sorry you are having a problem with the snow blower. So if a motor runs fine with the choke open, but doesn't run at all with the choke off, that usually means the air screw or idle screw are wrong. Lean Symptoms. ­ I­f you read How Two-stroke Engines Work, you learned that one big difference between two-stroke and four-stroke engines is the amount of power the engine can produce. I set each one to about 1/2 turn past the zero lash position. better option; however, if noise is not a problem at your airfield, and you want to keep things light and simple, the in-cowl muffler works great. If the choke lever is too short. Suzuki 15 hp 4 stroke choke issues but see no harm in trying on a 4 stroke modern engine. I've been reading a lot about DCR (dynamic compression ratio) to educate myself when discussing options with Cam selection. Starting Problems: Yamaha 90 HP 2-Stroke The engine runs like a champ otherwise once it is started and warmed up. This is a brand new replacement complete 21mm variator kit with rollers, fan, sliders, drive faces, and slide bushing for the two stroke Minarelli JOG 90 JOG90 and JOG50 chinese scooter engine. to find out which one you. Clean or replace the air filter as necessary. Then back them out 1. Race engines need as much fuel as they can swallow without sputtering! Clean running engines belong on the street, not the race track! A well jetted 2 stroke using a high quality synthetic oil will have evidence of oil at the rear of the exhaust system.