Hey Guys.

Just went and got my boat out of storage and brought it home to prep it for a trip. Hooked up the muffs and started squeezing the primer bulb. just as it started to get stiff, I heard/felt a pop then the bulb wouldn't firm up anymore. I checked the bulb and it is working correctly. I disconnected fuel hose to the carbs and can pump fuel all the way to the bowls. The fuel is going somewhere, but I can't tell where. The spark plugs are pretty wet with raw fuel. The motor will start if the throttle is advanced half way, but as soon as I try to bring the RPM's down it just dies.

Any suggestions?

Most likely a diaphragm broke in one of the lift pumps.

Is it an OX66? Those early 2k Yamaha's are known for chewing up the low pressure fuel pumps. Spend $100. Get this three pack. Replace the busted one. Keep to extra. https://www.amazon.com/gp/product/B088KS7TLG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Well guys, It's just a standard 3 cylinder 90TLRA Yamaha 2 stroke. But y'all are spot on. That pop I heard/felt was the diaphragm in the fuel pump breaking. Every time I squeezed the bulb, I was pumping fuel into the crankcase. The clue was the raw fuel running out the exhaust.

On a side note, I always wondered how that goofy pump worked. Actually it's pretty ingenious. Since it's vented to the crank case, the momentary pulses from the backside of the pistons cause that diaphragm to bounce back and forth (as long as it doesn't have a hole in it) and check valves in the pump itself allow the fuel to only get pulled through it. I love learning how stuff works.

Quick fix! New fuel pump installed, and she starts up even better than she did before. Thanks everyone!

Cheap insurance to carry a spare or replace them all every 3 years.

I was thinking the same thing. Since this old girl only has the one pump, I will rebuild the old one and hang onto it as a spare.