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Author Topic:   carb question (a little OT)
Dirt Roller

Total posts: 23
posted June 23, 2005 03:58 PM  
My friend has a boat with a 4.3 chevy and a rochester 2G. SOme debris got in the carb last year. We cleaned it up, new carb kit and all...
IT would pull 4500 RPM before, now it only pulls 3800. If the choke is closed a little, it will jump up to 4500. I tried raising the float thinking it was running out of lost 200 RPMs, so I lowered it a bit below parallel which helped get it to ab out 4000. Closing the choke a little still brings all the power back. IT runs and idles smooth without black smoke.
Should i lower the float more? All suggestions appreciated

Dirt Forum Racer

Total posts: 94
posted June 23, 2005 06:35 PM  
Sounds like you still have trash in it somewhere, make sure the power valve is working

Dirt Full Roller

Total posts: 60
posted June 24, 2005 10:52 AM  
It's definatly not your float. if it runs better with the choak closed the carb is running lean at wot. check all of the jets for trash and make shure the power valve is opening and not cloged. Basicly there is a restriction in there somewhere not letting enough fuel flow.

If it has wheels or a skirt, you can't afford it! But they shure are fun...

Dirt Forum Champ
Total posts: 1019
posted June 24, 2005 11:14 AM  
A blockage (trash, corrosion, etc) is probably in the air bleeds or the restriction tubes in the booster assembly. Double check that the emulsion tubes are clean and free of "gunk". They are the larger inner tubes with 4 holes in them that are on the underside of the booster assy.
Also, the marine carbs had .130" needle/seats and many of the over-the-counter kits only come with the small "street" version needle/seat. Slight fuel starvation may be caused by insufficient needle/seat flow. But I'm inclined to believe the small displacement engine this carb is on wouldn't need the big n/s assy.
Hope that helps,

Dirt Roller

Total posts: 23
posted June 24, 2005 06:01 PM  
Thanks for the input. He took it out today and it pulled 4200...a bit better. I had checked the emulsion tubes and the are clean. I suggested last year to put an inline fuel filter in, but he put it between the tank and fuel pump, so maybe the fuel pump diaphragm is shedding?
How do I check the power circuit? The plunger moves up and down.
I agree that we need to take it apart, soak it in carb cleaner, blow it out and install an inline filter between the pump and carb.

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