1992 Yamaha 2 stroke 40 MSHQ carburetor leaking

I just replaced all fuel hose and connectors. Also installed a 10 micron fuel water separator. I’m running non ethanol fuel. Next I ran a heavy mix of Seafoam to decarb . Motor runs great but now at least 2 of the carburetors are leaking. I’m think floats stuck open or needle valve. Before I open them up is there anything else I should look for? I’ve worked on a lot of small engines but this is my first outboard. It smoked like an old train while I run the Seafoam through it. Had nasty looking stuff in the water tank I ran it in.

Did you have a fuel leak prior to replacing fuel system components? I would suspect so. If you’ve ruled out the leak coming from the fuel pipes that connect carb and fuel pump, then yeah you’ll need to pull and open carbs.

Smoke from seafoam treatment is expected. Though the nasty stuff you mentioned in the water tank is coming from the cooling system, not from running seafoam. Wouldn’t run in tank anymore unless you wanna keep recirculating that junk thru the cooling system.

The leak was prior to replacing everything.I’ve been putting this part off and doing the fun stuff first.I was afraid it wasn’t good to run in a tank. It doesn’t like the muffs I have. I do any more than idle it’ll over heat. I have good water pressure from my hose. Wonder if removing the screens from the pick ups would help? I don’t want to over heat it again. The water pump is new also. I really appreciate your input.

Update. I was about to pull the carburetors today and decided to see where the fuel was coming from because of the location not all of it came from the overflow. I thought the screws were loose or the gasket was leaking. I cleaned the outside of the carburetors good even used a q tip. Removed the silencer and there I could see it was coming from the throat and running down. Made perfect since. After cleaning that up I hooked the tank up and it primed right up. After an hour I looked and no fuel leak any where not even the overflow. Primer was still tight so I put some pressure on it this time and waited another hour. No leak anywhere. The throat had some fuel in it but not much. Then I decided to run it and it ran perfect but I couldn’t make any fuel leak out. All clean still. I’m waiting to see what tomorrow brings. I don’t believe in a cure in a scan but Seafoam has helped the heck out of it. If no leaks it’s going for a lake test.

Good to hear. In regard to the overheat issue, given that you noted all that gunk in the water tank, I’d pull the head covers and scrape out all the gunk in the cooling passages, and replace the stats if you haven’t already.

I just looked up the new stat and gasket. I think it’s stuck open now. When I started it water came out the pee hose instantly and it usually takes a couple of seconds. Unless it’s the new muffs I have. Or the old stat is working correctly now. Lol it’s getting new stuff either way.