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1997 Yamaha 150 pro-v - Gas overflowing from carb

Ian Olow

New member
I'm having an issue with my 1997 Yamaha Pro-v 150 this week, first problem with it so far.
The problem started right after I filled my topside gas tank. I removed it from the boat and took it to an inland gas station (saving a buck) and once got back to the boat and hooked it up, primed the line with the plunger, she would not start (usually fires right up).

The plunger bulb does get hard when priming, but doesnt stay hard for long. I checked both fuel pump diaphrams which are in good shape with no holes/tears.

The main problem I do see is that gas is dripping/flowing out of the bottom carb and coming out of the air intake after I prime. I removed the intake and can see the gas coming out of the carb while I squeeze the primer bulb.

I've taken that bottom carb apart and cleaned it out. Still gas flowing from it as soon as I prime it.
What else could cause a carb to overflow besides a stuck float?
Any help would greatly be appreciated
 
The motor wont even start. I've torn down the carb and cleaned as best I could with carb cleaner. All ports/jets look clean. No debris.

I have a rebuild kit coming in tomorrow. I will be using this kit: Sierra Part #18-7756


It doesnt look like the seats are designed to be replaced on this carb. I see no way of getting them out, as there is no access to them from below, and topside they look like this:
http://outdoorpowerinfo.com/repairs/images/kohler_command_v-twin_nikki_carb/float_needle_seat.JPG


Thats where I am as of now....hoping this rebuild kit does the trick. Looking at needles I see no burrs or anything they could get hung up on, but who knows. Been raining cats and dogs here lately so working on the boat has been hard. Will give it a go after work tomorrow and see where the rebuild gets me. I will make sure to measure my floats.
 
Will not start? Not even try to start? Do a compression test and check for spark. Also do a voltage drop test at the starter while cranking the engine. If the starter is not cranking 300-350 rpm, you will not get the engine to start.
 
Just wanted to update and thank you guys for your help/input. I feel dumb, but relieved. Found a break in my kill switch wire. After rebuilding the carb, which I still think was needed as it was leaking, the motor still wouldn't start and I found I had no spark. A quick search on the forums lead me straight to checking the kill switch, and bingo. Repaired wire, she fired up in about a second and a half, running like a champ.
Being new to outboard motors, I learned alot this week. I plan on breaking down the other two carbs next month and rebuilding after I take her off the water for the winter so shes ready for next year.
Thanks again!
 
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