Carb Question

[krazykatz911]

I have 4.3 volvo penta engine. (2005). Has the holley 2 bbl carb (I believe).

I cleaned the carb with some carb cleaner. I have this funny suspicion that I am running rich, seems to go through gas pretty good. Anyhow, engine runs great, except on shutdown after a hard run, it will diesel, and sometimes when I go to nuetral from a hard run, the idle is really high, only able to get it back down by snapping the throttle, then it settles. ???

And it is not a sticking throttle cause I have added secondary throttle return springs that bring it back real strong.

Only has 110 hours on motor.

Anyway, when looking down into the carb when running:

When I snap my throttle, and am looking down the carb, the second after the throttle is snapped, I see fuel squirt down on top of the throttle plates. Happens every time.

is this normal?

 

[6meter]

Re: Carb Question

Its dieseling cause the idle is to high, throttle shaft ISN'T set back. Sounds like you may have a worn throttle shaft or throttle body. Extra return springs won't help. Or the lower butterfly valves are binding in the venturis. Hard running usually dosen't produce good gas mileage. The carb cleaner just washed the outside of your carb only. If your problem started after the washing, its too clean.

 

[krazykatz911]

Re: Carb Question

No, Problem has been there before cleaning. Worn Throttle body / carb at 110 hours?

Is the fuel squirt normal?

 

[Fireman431]

Re: Carb Question

Can you put a vacuum gauge on it and properly tune the carb first? Also double check your timing against manufacturers specs.

 

[fossill]

Re: Carb Question

Is the fuel squirt normal?

Yup, thats the accellerator pump circuit. If it dont do that you get a hesitation or stumble on throttle advancement.

 

[6meter]

Re: Carb Question

Worn Throttle body / carb at 110 hours?

Would seem premature, check the side play in the throttle shaft. Also check to see if the butterfly valves are sticking on the throttle body or manifold. Snapping the throttle to get it down to idle says you have a problem somewhere. Might try disconnecting the throttle cable from the carb. That could be binding or out of adjustment.