Dead spot in throttle

[heikkila31]

Hello! I have a 1985 larson boat with a 4 cyl 120 horse GMC engine with breaker points. There seems to be a dead spot in the throttle when i put it down. It completely falls on its face and bogs out. I have rebuilt the carb/accelerator pump, changed fuel filter, changed points, wires, plugs, condensor, plug wires, and am at my wits end. I am thinking of changing to an electronic conversion kit and getting rid of the point system. Any thoughts? Help!!

 

[heikkila31]

electronic conversion kit

electronic conversion kit

I have a 1985 gmc 4 cylinder 120 horse in a larson 175 DC. I have a dead spot in the throttle and am thinking about changing to an electronic system instead of the breaker points. Any thoughts? I have already went through the carb/carb accelerator pump, cap, rotor, points condensor, plugs/wires, and am at my wits end. It happens every time i hit the thr0ttle in the same spot. Falls flat on its face. Help!!

 

[Don S]

Re: electronic conversion kit

Re: electronic conversion kit

Go for it, but don't expect it to fix your dead spot. Sounds more like a carb problem, if you had the dwell, timing, and carb idle mixture set correctly. Lots of people claim to have "Rebuilt" there carb only to find out they had no clue of how to actually do the job properly, and didn't have the equipment or knowhow to do the job to start with.
Above I mentioned idle mixture, that is not something that is done buy turning the mixture screw/s out 1.5 or 1.75 turns as the book states. That is nothing more than a preliminary adjustment.
Set the dwell to specs, then set timing and check advance timing, then adjust idle speed and mixture to the engine.

 

[MikDee]

Re: electronic conversion kit

Re: electronic conversion kit

Sounds like a carb accelerator pump, or a metering valve (similar to an accel. pump but vacuum operated), or a late timing issue. Installing a pertronics, or other electronic ign. system, you have to deal with the shift interrupt switch, that momentarily cuts the ignition to shift, go by the manufacturers directions with this.