1958 Seahorse 7.5 hp - puking fuel out of the intake

[OldSod]

Ok. so let me begin by admitting that I just refurbished the carb and suspect that I may have forgot to install the seal on the new valve seat when I replaced that along with the needle valve. How vital is this little nylon washer? I've replaced many valve seats before, and many didn't have seals, and even those that came with didn't leak as badly as this if they were worn, or damaged, or missing?
Would it's absence cause the needle valve not to seat and allow fuel to bypass?
If I open the 2 line tank to relieve the air pressure the leaking stops but I have to drain the flooded carb before I can restart the motor.
On the up side - at least now I know the motor runs after a complete rebuild!

[Dave Neptune]

Welcome. Those "seals" are important for absolute sealing. If there is one intended there it is for a reason like needing to complete the seal.

Your needle and seat could be working just fine however fuel from the feed cavity can leak in through the threads and the seat in the casting of the carb. It would be a slow leak at best and once the engine is running hard enough the leak will become mute but when shut down the leak will continue.

My dad had a Owens woody with a pair of 1958 Seahorse 50's, did it ever like to guzzle fuel!

Dave Neptune

[Dave Neptune]

Part II

It could also be a leaking reed valve not closing completely as well.

Dave Neptune

[OldSod]

Thanks Dave,
Yeah, although I didn't notice one in the rebuild kit, T-Mike installs one in his rebuild video on YouTube so it must be required.
I think that as opposed to preventing leaking along the threads it's the thickness of this seal that lowers the seat in the upper body of the carb allowing the needle valve to fully seat and close off the fuel supply. If this doesn't work then I'm going to try a new float since it's a known fact that modern fuel (ethanol) lowers the buoyancy of the original cork floats.

[ndutton]

I'm going to try a new float since it's a known fact that modern fuel (ethanol) lowers the buoyancy of the original cork floats.

Unless there is a saturation factor of ethanol into cork, ethanol blended gasoline would actually cause floats to be more buoyant. Ethanol is more dense (heavier) than gasoline so a blend would also be slightly more dense.

[Dave Neptune]

You could probably find a sealing washer at a parts house or hardware store.

Check the float level too, both open and closed. Only bend and hold only the tabs with small pliers when doing so. Do not bend when holding a float.

Dave Neptune

[OldSod]

Yeah, I wish OMC had used brass floats back in the day. The cork floats are know to absorb ethanol and lose buoyancy and some folks coat them with airplane "dope" or even crazy glue to seal them without adding appreciable weight. The Teleflex kit I bought thru Sierra didn't come with a float since unless you want to fork out $79.00 for the BRP kit they all come with a cheap plastic float that I wouldn't trust to last very long. Unfortunately, I can't find just the BRP float alone that ships to Canada unless I want to pay an additional $30.00 shipping. Ironic, I thought Bombardier Recreational Products were a Canadian company. Tabernac!

[Dave Neptune]

Plastic floats today are actually pretty good, given a choice between cork and plastic I'd go for the plastic. I have seen them in many production vehicles. Besides cork does not like the E fuels so why limit your choices.

Dave Neptune

[OldSod]

Yeah Dave, that may be true but when I look at the architecture of these old carbs from the 50's and 60's and see brass, stainless, real cork, and real rubber, I just don't feel cozy with plastic and tin replacements. Last night I tore down a spare carb to have a look at the seat and it doesn't look as though that carb had ever been refurbished. The seat does have what appears to be a rubber seal/gasket/crush washer (et. al.) at the top of the threads so I'm about 90% certain that this is the cause of my flooding issue in the rebuilt one. Without it the seat would thread in too high in the carb body to allow for the needle to fully seat in the jet and close off fuel.
pic att. Cheers!

[Dave Neptune]

I doubt the washer thickness would not make the needle close fully unless the adjustment was way off. Most old OB carb specs list both a float closed level the common setting and the max drop setting so the needle won't jam when angled at the bottom of the travel.

Again, don't worry about the plastic float. Notice that there are almost no cork floats in anything newer and a good percentage are plastic.

Dave Neptune

[Al Schober]

With an old 2 stroke outboard, I'd be very leery of the reed valve. They're a weak link for those engines. I had a brand new Evinrude 15HP that died in it's first month - a plastic tab from the choke control broke off and lodged in the reed valve. Fixed under warranty, but it was a pain in the a.. returning the engine to the point of sale.