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F20 Carb Enrichment?

I

istock1

New member
Hello,

I recently bought a small skiff with a 2008 F20MSH on the back. It takes forever to get is started ... 5 minutes of pulling and a bunch of starting fluid is the only way to do it. Once I do get it running it revs really slow and putters out when I detrottle. I cleaned the carb and it starts better but will stop if I give it too much throttle, so in a fit of rage I bought a new knock-off carb online. With the new carb the engine starts with half a pull from cold and revs great, but it smokes like a fog machine.

My hunch is that the original carb is set too lean and the new carb is set too rich. Does that sound like a reasonable diagnosis? I bought the boat from a widow who had not run it in a while and there was a bunch of crud in the original carb when I cleaned it ... but I am not sure why it would run so lean? Does anyone know if there is a setting I can change that might help? I see an adjustment screw that interacts with a plunger right next to the butterfly spring, as well as a brass screw in the body above the butterfly next to the baffle thing on top of the carb. Am I on the right track?

Thanks,
Ian
 
Fuel enrichment for a cold start is provided by the Primestart component mounted on the carburetor.

The plunger that you mention is for additional fuel enrichment when the motor is accelerated.

If the motor is cold then the Primestart being deficient on additional fuel can adversely affect the ability of the motor to accelerate.

I would suspect that the carburetor has not been thoroughly cleaned. Easier said than done. There are many orifices and passageways that can be difficult to get clean. Best bet is to use a heated ultrasonic cleaner with a good cleaning solution. With the carburetor being thoroughly dismantled. Rod out the orifices and passageways with soft copper wire. Flow water through the carburetor making sure that all passageways are free and clear. Pay good attention to float bowl.

EPA controlled Yams can be overly fussy given the lean condition under which they run. You might want to use an oversize idle mixture jet to see if that improves the situation.

Regarding the smoke with the replacement carburetor, what colour is the smoke? Should be black or gray.
 
Boscoe,

Thanks for the reply. I cleaned the original carb but just with a spray can of "carb cleaner" ... I picked up an ultrasonic cleaner this morning and will give it a shot.

The smoke with the replacement carb is white or light gray, and it smells like gasoline. Does that sound like it is running rich, or something else? Any idea on how to change it? Ideally at the end of this I will have two working carbs, instead of one with too little fuel and one with too much (or whatever the issue is with the replacement).

Thanks again for everyone's help.

Ian
 
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