1990 Yamaha 115 Fuel Problem ?

[Louisianagames]

I have a 115 Yamaha (1990) I ran it every week til after the 4th of july.. Had it sit up since waxing the bottom and repairing the trailer..

The problem:
It was cranking up fine, but did notice that it would start bogging down.
If I hit wide open throttle it would hesitate 1 sec. then jump and go. Well today I went and checked the fuel filter, it had a few specs of trash, nothing major at all. It got to the point where it would not run..took a long time to crank ... Finally got it to crank and idle (1000 Rpm's) I hit the throttle wide open and it fell on its face..I hit the electric choke and it took off wide open then slowed down and dying..

I pulled the carbs and fuel pump. Cleaned the carbs but did not see any blockage.. as for the fuel pump, it looks good.

i could use some pointers ..
Where is the low speed jets spray from? I have some pictures attached.

I replaced the plugs after doing that i noticed it had a tiny spray of fuel from a pin hole in the bottom carb line when I primed the bulb..I fixed it and no change..

I'm going to get a new fuel pump in the morning. The boat is still in the water here at home..Bad part is I'm goin to Destin tomorrow evening and I think I might be taking the blow up pool raft if I dont get it up and goin..ugg

Anyway all help is much appreciated..I'm mechanically inclined, so let Me have it!!

Thanks!!

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[Louisianagames]

Re: 1990 Yamaha 115 Fuel Problem ?

pics of Choke plate side.

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Picture of the bottom with floats removed (below)

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Picture of the backside throttle plate (below)

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[Louisianagames]

Re: 1990 Yamaha 115 Fuel Problem ?

Also..one question...will the fuel pump diaphragm stretch out to far if its worn out? I cant find a leak/hole in it..

I'm fixing to put it back together and test it...I have it in the water at My dock.
Thanks.
Lag

 

[Louisianagames]

Re: 1990 Yamaha 115 Fuel Problem ?

Well I'm still stuck, any suggestions?

 

[djarrett]

Re: 1990 Yamaha 115 Fuel Problem ?

When you hit the chokes you cut off the air, forcing a rich condition. By it waking up i would think that just for an instant the air fuel ratio was closer to correct.

Sounds like you are running lean. I personally would not run it like that much, there is a good chance you'll kill it.

I would try pumping the bulb to see if it helps, that will bypass the fuel pumps. If it stays flat theres a restriction in the fuel line somewhere. I would start at the fuel pick up in the tank and work toward the carbs. Try splicing in a piece of clear hose and check for air bubbles also to see if its sucking air too. There is some pretty good reads at the top of the maintence forums.

Good luck and hopefully someone smarter than i will be along shortly.

 

[Louisianagames]

Re: 1990 Yamaha 115 Fuel Problem ?

Thanks Djarrett for keeping My sanity ..
Well I went and got a new fuel pump, I could not find any clear hose (tried 5 parts houses) gonna change all the fuel lines put the new pump on..Goin for the Hail Mary... wish Me luck..!

Thanks again !
Lag

 

[Louisianagames]

Re: 1990 Yamaha 115 Fuel Problem ?

Up and rolling !! Thanks for backing Me up Djarrett .
I replaced all fuel lines, new bulb, cleaned carbs, new fuel pump, 2 new filters. And runs like a new one..!

Its a 1990 Yamaha 115 and
My Boat is a 1977 17.4 Mckee Craft Dual console Southporter..