93 150 Fast Strike Idles rough when cold

[greg]

I recently replaced the power

I recently replaced the power pack on my Johnson 150 Fast Strike 1993. It now runs fine eccept when it is cold and the quick start has the idle advanced. During the fast idle it has a bad miss but when it warms and the idle slows down it runs fine. Any tips on where to start looking?

 

[joereeves]

"Greg... There are many engine

"Greg... There are many engines w/o the fast start that would idle rough when cold, however I'm assuming that your engine ran fine at one time, then the powerpack failed. Shortly thereafter, you replaced the powerpack and that's all you did, and this problem existed immediately.

If the engine sat for some time, a carburetor could foul, but that's not likely as you say that it does idle once the fast start drops out. Frankly, I've never ran into a problem such as that.

After the fast start drops out and the engine is warm and idling smoothly.... if you increase the rpms via the throttle handle to correspond to the rpms that exist via fast start.... does that bad miss come back?

Joe

"