1987 125 Idle Mixing Screws

[rammerjammer05]

1987 Force 125 1258v7b. I was adjusting the idle mixing screws yesterday and got the bottom carb set at about 1 1/4 turn out from seated. When I moved to the top carb I stared with it at 1 turnout a turned it clockwise (in) but the engine never changed.Got the screw all the way to seated. Basked the idle mixing screw back out to 1 turn out from seated and started to go counter clockwise(out) and again nothing with the motor ever changed. Each time I was doing this I would turn the screw only a little bit at a time to all the engine to catch up. Do I have something wrong with my idle screw on the top carb or should I just set it to 1 1/4 turn out from seated like my bottom carb. Haven't took the screw out yet to see if it's damaged but plan on doing this tomorrow along with a decarb.

 

[jerryjerry05]

Re: 1987 125 Idle Mixing Screws

Set them at 1 and 1/8th and leave them.
If you get no change: do a compression test.Then a spark test.Then check the diaphram in the pump.J

 

[Frank Acampora]

Re: 1987 125 Idle Mixing Screws

Without being there and hearing the engine it is very difficult to comment. IF it were my engine with the same symptoms, I would first check compression and spark to be certain the top cylinders are firing consistantly. If the engine was OK mechanically, then I would remove both carbs, disassemble them and clean them. If I found any damage or problems I would fix them. This should be done before running the engine in the water.

Reason: If the top carb is running too rich because of a stuck inlet needle, no adjustment on the idle mixture needle will do anything. The engine will run poorly and use lots more fuel.

If it is running too lean, again, sometimes the needle may not adjust properly BUT real damage can be done to the engine.

It always pays to be overly cautious when carbs show any abnormal operation or you can not adjust as the manual describes.