Re: 1992 40HP Force has idle and start problems
I'm not familiar with your motor's year, so I'm looking at a diagram online and I'm making some assumptions. There are a few sites that show these diagrams and this is one of them:
Evinrude Parts - OMC - Mercury Outboard Parts - Mercruiser Parts. I find it easiest to search by serial number instead of by model. These diagrams could be a lot of help to you. They certainly are for me.
On the carb you'll have the idle mixture screw that has a tension spring around it. This is for fuel air mixture. Check its current setting by counting the number of turns it takes to screw it all the way in until it bottoms out. Don't screw it in tight because its soft brass and the shape of the needle can be damaged which can affect its setting when compared to others. On mine and maybe other force 40s the proper setting is 1 and 1/16 out or close to it.
The idle adj screw is what you adj to control the idle. It is not on the carb. It will be attached to one of the linkage arms with a lock screw. The screw is stainless and pushes against a flat spot on the engine block when it's adj'd in. Just so you know, if you adjust the idle screw in or out and find a better idle setting you will likely need to adjust the linkages so that the motor will return to that idle setting when you return the shift lever to its neutral position. My experience found that after adjusting the idle it was best to start adj the linkages from the lowest (first) one (where the throttle cable pushes on the first linkage) and work your way up to the carb until the linkages are tight and the throttle cam hash mark points to the middle of the rocker screw.
The throttle control arm that passes thru the carb and controls the butterflies has a small phillips head rocker screw on the end of it held in place by a nylon locknut. This screws body is not straight. It has a black plastic covering like a tall washer over this rocker shape. The shape of the rocker screw helps to make proper contact with the throttle cam attached to the linkage. The throttle cam is a curved piece of flat metal that is the final part of the linkage that presses against the rocker screw to rev the engine.
If you have a tach on your dash you can use it to set the idle speed. Like I said be prepared to adjust the linkages after doing that. If you still have a decal on the engine block it will tell you the correct idle speed. This speed is while it's in forward gear (not in neutral) and when it's warmed up. Mine says 800RPMs and that seemed to be right for my motor. In neutral, my RPMs are about 1000.
I hope this helps.:thumb:
