I've got my buddys 99 arctic cat 250 2x4, he says that the only way he could start it was to use the rip cord. The battery was dead but even with cables on it, it would not go. After it started it would rev up on it's own then stall. So I cleaned the carb and replaced the battery and was able to get it run with the electric start. After it was revving and stalling and a few back fires, it won't run at all. I've got good spark (new plug) checked around for air leaks found none. It seems like timing because I've got fuel, compression, and spark. But it looks to me that it is a push rod engine so the timing shouldn't be able to go out. Or can it? I'm lost and need some help, any help would be greatly appreciated.

 

Not likely to be the timing as it is timed off the crank, no points and I've never seen timing change without a major breakage problem. How old is the fuel? New fuel is a requirement when dealing with a machine that has set longer than a couple of months. Flush the fuel tank and the carb with the new gas (there is a drain on the carb bowl that allows you to do this). Does the problem exist in the reserve position on the fuel valve? Have you replaced the spark plug? Seafoam in the gas never hurts.

 

I've drained the tank and cleared the lines, checked flow from tank all seems good, new plug, tryed running without air box to eliminate the air filter. no luck

 

Compression test? Have you checked for spark? Have you tried squirting some fuel in the carb throat when cranking to check if the carb is still delivering fuel? It only take 3 things for the motor to run: 1: compression, 2: fuel, 3: Spark at near TDC. With it running for a while then quiting I would suspect the carb plugged back up.

 

I have put fresh gas directly in the cylinder and it won't fire. I've had the carb off and cleaned it like four times. I've checked the exhaust and it is clear. I'm so confused. I'll try the carb again and see what happens, the carb is the only thing that makes sense.

thanks for your response

 

Do what Bear said and check compression. you have checked the other stuff, make sure you have compression or you won't be able to pull fuel into cylinder.

 

I modified my compression tester and you guys are dead on, it was approx 60 psi so I guess the next step is to pull the cylinder and head to check it out. thanks guys

 

I wouldnt do that just yet i just had this porblem. Is the plug looking wet when you pull it? Heres what i did got on a level surface tipped the atv over so the cylnder was on the side and turned it over t,he whole bottom end was loaded with gas ,let all the gas run out the plug hole. tipped it up and it started right up. It was due to choking the **** out of it and dirty carb. If you use the starter when on the side make sure the plug will not arc on anything or you will be on fire. I pulled my plug and taped the cap just to be safe. I had to use the starter because i had no puller. Im not sure if these engine have a case drain plug but if thet do use that

 

I would suggest checking the valve clearance before pulling the head off. May just need the clearance set, the intake valve is usually the one that needs it the most. If it is to tight (not enough clearance) the valve won't close and piston can't pull fuel in to cylinder. Also if it is open that could be reason for low compression reading. Only take you about a half hour to check. Good luck, TORK

 

I will chack valve clearence before going much futher. Does any here know what the clearence should be?

thanks again guys.