Idle Question

[san dimas]

Hello everyone;

I have a 1997 Force 9.9 that runs perfect except that I can't get it to idle below about 900 rpm in gear in the water. I thought maybe it was sucking air somewhere but it does make sense since it runs so well. It will idle all day and run wot all day. When I had the carburetor off I noticed that the throttle butterfly (not the warm up butterfly) had a hole or a slot in it, so it seems I would have limited control over the idle anyway with air being able to get past the butterfly. Could this slot be some sort of emissions control? It seams to me that I should be able to adjust the idle down untill it dies. I would apppreciate any help you can give me.
Thanks.

 

[jerryjerry05]

Re: Idle Question

The air screw should be set at 1 turn out and adjusted from there.
If it won't idle,then the low speed jet is clogged or dirty.
A speck of dirt the size of a pin head can stop it from ideling.

 

[roscoe]

Re: Idle Question

Is the butterfly closing completely?

Carb is secure and tight to the motor?
No damage to the gasket between the carb and motor intake?

Possible the diaphragm in the fuel pump has developed a small hole, which would leak fuel into the crankcase, causing a slightly flooded condition. Its an $8 part if you decide to replace it. In any event, keep it in mind if you get into flooding situations in the future.

 

[san dimas]

Re: Idle Question

Thanks guys.
The air screw is working well. I can kill the motor by going too lean and I can kill the motor by going too rich. I have it set in between at the fastest idle. Should I set it rich to slow the idle down? Doesn't really seem right. When I had the carb. off the butterfly was closing all the way. I can try to force the butterfly closed with a screwdriver but it doesn't close any further and the idle remains the same.

 

[san dimas]

Re: Idle Question

I will check out that fuel pump diaphram, it probably wouldn't hurt to replace it anyway.

 

[Jiggz]

Re: Idle Question

I will check out that fuel pump diaphram, it probably wouldn't hurt to replace it anyway.

Unless you have $$$ burning in your pocket there is no need to replace the fuel pump as it is working perfectly, what you need is to locate the idle screw and back it out a little bit. As for the air screw a little "rich" would not hurt.

 

[san dimas]

Re: Idle Question

There is an idle screw on the left hand side of the motor (tiller side) that I can adjust untill the stop is touching only air, makes no change in idle speed. I can speed the idle up with it but the speed will only come down so far. The other screw is on the carb linkage that is adjusted so that the throttle (pickup roller) just begins to open when a line on the throttle cam is lined up with it. Maybe I'm being too anal about it and should just run it There's no crashing of the gear box or anything. It just bugs me because I like everything to be right.