I have an Arctic Cat Cougar 500, year 1990. The engine is air cooled. The problem is that I don't get any vacuum for the gas pump. I tried to look for a lower seal leak, but I could not find one. The engine runs fine and actuates the gas pump when the engine is running with high rpms. It doesn't idle at all and is very difficult to start, because there is no gas pressure when not running with high rpms.

I actually took the engine out and blocked the intake holes and the exhaust holes. Then I put air though the vacuum line and put the engine in our bathtub. I didn’t see any bubbles so I assume no leaks in the lower seal.

My question is that should the crankcase separate the cylinders “air space” somehow? I am thinking that could it be possible that I don’t get any vacuum because the crankcase is “leaking” the vacuum to the other cylinder’s side internally? You know that when you turn the engine, the pistons go up and down so that one is up and the other is down. The vacuum hose comes from one side and when that side piston is going up the other one is coming down and at that time the air flows through the down coming piston side’s intake hole and gets to the crankcase and causes the problem. Is this possible?

What should I do?

Thanks!

 

If you want to get some really good answers for snowmobile questions go www.arcticchat.com, there are some guys there that know the machines inside and out.