Yamaha 8MSHV / 8hp / 2 Stroke Fuel Pump

[TvZ12345]

Inherited this outboard with a dinghy purchase. I am a self proclaimed DIY hack. I took the carb off and cleaned; emptied the fuel tank and flushed new gas through the line and carb When priming the engine the fuel pump spits a fine stream of fuel out through a ball type valve on the top of the pump. I dissembled the fuel pump (again) to make sure I had oriented the the gaskets the proper direction. I think I have. Fuel still squirts out the valve on top. What's the logical next step? Replace gaskets? Did I botch it by swabbing the gaskets membrane with a paper towel on the initial cleaning? Or, by using light pressurized air on the whole thing? Thanks for your help.

[TvZ12345]

As a follow up question: Is there a source for manuals for these older engines? Manuals that are not priced at $90? Thanks again.

[99yam40]

not understanding a ball valve on top of fuel pump, but I am not familiar with that motor

[zenoahphobic]

not understanding a ball valve on top of fuel pump, but I am not familiar with that motor

Could that be the air pressure equaliser hole? Probably indicating the diaphragm inside the vacuum fuel pump is leaking and needs replacement.

[TvZ12345]

Gets more bizarre, I replaced the diaphragms with OEM ones, no leak out of hole, engine idled down like it was running out of fuel (like it did to start the work I've done thus far). Which btw I emptied and cleaned the tank, cleaned the fuel line, replaced the fuel filter, cleaned carb and jet. It starts and purrs like a kitten, with no fuel pump on but carb bowl full. So, after I replaced the diaphragms and it acted up again. I ran the fuel out, primed (as of now I've got no fuel leak out of the vacuum / pressurization hole, but while priming a little too firmly there was a mild pop... And fuel started squirting up from the hole. It runs utterly perfectly, with the leak, and seems like it's running out of gas when it's not leaking. Suppose I'll replace the pump now.

[panasonic]

This your carb? 41Itmu-lOaL._AC_SY400_.jpg

[panasonic]

https://www.crowleymarine.com/parts/...SABEgILTPD_BwE

[panasonic]

I would not think that is a valve. The ball is a plug for a hole that was drilled in the carb during manufacturing. Should be no fuel leaking out of there.