Bogging

[Keith A Walker]

I have a 1998 Force 125 recently thoroughly checked out in a reputable shop and "de-carbonized". I starts and idles consistently - as good as new, but it usually boggs down when the throttle is opened. Typically with the throttle fully opened it will run very smoothly at 4000 rpm (as if I was only applying only partial throttle) and then suddenly will go to full power at about 7000 rpm. Once it goes to full power it will run perfectly as long as I want, until I slow back down and then it will usually bogg as before when applying more throttle. When transitioning from bogging to running perfectly it usually lurches - that is to say, it transitions back and forth from bogging to running a full power repeatedly about once per second.

Sometimes, if I go from full throttle to idle and the back to full throttle it stops bogging and goes back to full power. There is never any ?in-between? - It?s either 4000 rmp (running smoothly) or full power 7000 rpm?

This problem has been very, very consistent over the past 2 years. I don?t think it is fuel, oil or spark.

 

[TwoFish]

Re: Bogging

Have you had a look down the throats of the carbs? Are the butterflies in the carbs opening up fully or are they sticking at some point?

Another thing to look at is the timing advance linkage. Is it sticking or has something come loose?

 

[jerryjerry05]

Re: Bogging

Three things to make it run:fuel/oil compression,spark.
You say it's not fuel or spark and the comp has been checked.So one of them is doing something.
Those motors have a stator that can break down above 3000 rpm's so go to outboardignition.com and do the stator tests and check the other stuff too.
Possible coil breaking down?How are the plugs burning when it happens(pull and check)?
Possible fuel pump diaphram?
Possible loose connections?
Possible the fuel line is not working right? The squeezie has a valve that can close.There are inline connectors that leak and suck air,the tank vent partially clogged,the pickup tube clogging?
Possible water in the fuel?
Check these and see.What were the comp results?J