I've got a question I hope someone can answer because I know next to nothing about carbs. I went to use my boat this weekend and when I fired it up there was fuel leaking/seaping from what looks like some sort of plug on top of the carb float bowl. Luckily I noticed this before heading to the lake. Any ideas as to why it might be leaking from there? I took it apart and couldn't see any way of tightening that plug or sealing it. Any help would be greatly appreciated, unfortunately my warranty ran out in August. Picture attached of problem area. Thanks in advance.

On automotive versions of that carb, there's an adjustable float valve in that spot. I'd guess there's a float valve under the cap that cannot be adjusted. No idea why it would leak other than a simple manufatcuring defect. I imagine pressurized fuel is supposed to be on the underside of that plug. Can you order a new primary fuel bowl assembly and put it on?

It might be possible that the plug has come undone/unseated and is starting to leak out because like dave said I do believe the fuel runs under there.

I think that is a replaceable plug. Take it to a carb shop and have them replace it for you. Shouldn't cost much to do.

Thanks guys for the replies. All of you are correct, it is just a plug above the needle & seat that didn't seal properly, and when the bowl is full the plug is allowing fuel to seap through. My guess is the volvo red paint helped mask the problem for a little while but finally gave way this weekend when I fired it up. So for the time being I cleaned off the paint and sealed up it with some JB Weld epoxy. If that fixes it then great, if not I will try to get the plug replaced or a new fuel bowl. Thanks again for your help.

I thought I'd mention it just in case; it's not one of these carbs, is it, and it's leaking because of excessive fuel pressure in the fuel bowl?

VOLVO PENTA REPORTS THAT A NUMBER OF RETURNED (UNDER WARRANTY) HOLLEY CARBURETORS SHOW EVIDENCE OF CORROSION INSIDE FUEL BOWL AND/OR ON METERING BLOCK & MAY RESULT IN A FIRE AND/OR EXPLOSION HAZARD DUE TO FUEL LEAKING IF IGNITION SOURCE IS PRESENT. REQUIRES INSPECT AND REPLACE DEFECTIVE CARBURETORS. DNR DATED 11/21/07 - MODELS 3.0 L, 4.3 L & 5.0 L SERIAL NUMBERS RANGING FROM 4012177265 THROUGH 4012204622. IF DATE CODE MARKED ON CARBURETOR IS BETWEE 3355 (DEC 1, 2005) AND 2436 (AUG 31, 2006) CARBURETOR MUST BE REPLACED, SEE VOLVO PENTA SERVICE BULLETIN 23-1 19 01."

Graham

Underneath that plug is your float operated needle & seat. If it is not closing for some reason you will flood the float bowl with gas and it will leak out anywhere it can; it would also run rich and /or flood out and run very poorly. It could be a mal-adjusted float allowing too much gas in the bowl or quite often the float will become saturated and not float enough to close the needle & seat. If you weigh it against a new one and it is considerably heavier; that is your problem. If it is a hollow brass float it may have fluid inside (indicated by shaking it) which indicates a leak and will have the same effect.

Bottom line is you may have stopped the leak but may find your problems are greater than that, requiring internal work on your carburetor.