I just bought a used 2001 Arctic Cat 250 4x4 from a guy who said the machine was running okay last year but hasn't been run this year. I should have suspected something was wrong when I noticed he didn't have a spark plug in the engine, but he said he had pulled it out just to see if it needed to be replaced...I suspect its been out for months so who knows what may have fallen in there or why he really pulled it out to begin with.

Anyway, the machine won't start but it does have good spark to the new NGK spark plug and turns over fine with the electric start and pull start but it doesn't fire or attempt to start. (For purposes of testing I removed the air filter just in case it was dirty, and I ran a new fuel line to a can of fuel rather than the tank just in case there was a plugged line). The motor just cranks over.... No fire. Nothing. Just the sound of a happy starter spinning the motor over again and again. I pulled the plug out and put my finger in the hole and cranked the motor and it pushed out my finger and seems to have good compression. I then tried spraying starting fluid down into the cylinder and then quickly screwed the plug back in and put the plug boot on and pushed the starter button...Again, the motor cranked over again and again, but no spark or signs of life. I then tried pulling out the plug, and just cranking it without any plug in there to blow it out. I then poured about a straw full of gas down into the cylinder and put the plug in and the boot on the plug. Same thing happened, motor cranked over and no fire or attempt at starting. In disbelief I tested my spark plug again on the side of the engine, still sparking away with a good spark.

I'm not a mechanic, and am not sure what to try next without taking it to a shop (which I'd rather not do). Any ideas or suggestions?

Thanks!
Matt

 

I would check the compression first. The intake valve could be too tight, and its loosing too much compression to start.
With the air filter off and the air box lid off, its gonna be very lean...and that can keep it from starting too.
If the compression looks good, then id clean the carb and make sure the pilot jet isnt plugged up.
Have you tried starting at 1/4 throttle? This by passes the pilot jet.

 

Pull the spark plug and squirt some gas in the hole. Reinstall plug and see if it fires (it won't continue running, but if it fires there is no fuel in the cylinder). I suspect your carb is gummed up and not passing any fuel after sitting so long.

 

I checked the compression with a tester today, reading around 40PSI. What does that mean? Also, I've tried squiring gas into the cylinder but nothing came of it. What should I do next? Thanks! Matt

 

Probably a stuck valve or a jumped timing chain or bad rings. Either way the head will probably have to come off. Before you do that, squirt a some oil in the cylinder and recheck the compression. If it comes up a bunch, the ring are bad. If not it is valves or a blown head gasket.

 

Before taking the head off, check the valve clearance on the intake valve, and exhaust valve. My guess is they are too tight, those motors were known for the intake valve tightening up.

 

True, you should check the valves settings before pulling the head. But I must have a strange 250 as the valves have never been out, so I tend to not see this as a problem.

 

We had a few 250's that had valve problems. Arctic Cat had some engines that had soft heads where the seats would settle in to the head and would take several settings before they would stay set. Arctic Cat said that if they didn't come out of it to let them know but all the ones we had finnaly held their settings. Bear is right though, 250's in general are a solid little machine.