1996 Yamaha 150 carb leaking fuel. Need help

[fsujack21]

Hi all,

I have a 1996 Yamaha 150 that when I prime the bulb fuel leaks/flows out of the top front of the middle carburetor before the bulb is hard. I had rebuilt all three carbs prior to last season and did not notice any issues. I researched some previous threads and the suggestions were to check the float height or the needles being stuck. I pulled that carb and one of the floats was in fact out of spec. I adjusted to the correct height and checked that the needles were in good shape. Ran some compressed air through all the jets to be safe and put everything back together. The problem still exists?? I'm at a loss what am I missing?

Thanks in advance!

 

[fmt2bx]

No Title

FsuJack, I feel your pain.... Just went thru the exact same situation with my 1990 130HP yamaha. Looks like your carbs are very similar.

So, I am going to assume that you cleaned them thoroughly like I did and had a good look at your fuel filter as well as fuel line. If all looks good and you still have this issue. This might help.

1- The needle seat isn't adjustable and needs to be clean, I had them soaked in carb cleaner, was a bit better but not 100%
Here is a video that might help do the job .

https://youtu.be/IwyF4mzv0wI

This is after cleaning:

2- The gasket. I'll post a picture but you can see that on one side the gasket ends up very close to the float. It is obvious by comparing the 2 sides that one side has much more clearence. I read a post from a Yamaha owner who had the exact same issue and suspected that the bit of extra (useless gasket) might curl up and prevent the float from moving freely.
I cut a tiny tiny piece of that gasket and that along with the cleaning of the needle seat solved the issue.

more pics bellow.






I hope this help.

Cheers and good luck.

 

[fsujack21]

Ok thanks for that. I had cleaned them pretty thoroughly and the seats appear clean so I doubt that is the issue. The gasket clearance is something that I didn't think about. I will give it a try in the morning. Hopefully that solves it. Thanks for the help and I'll let you know if it works

 

[fsujack21]

Ok I got it fixed. I tried both the remedies that you listed to no avail. I polished the seats using a q-tip, cordless drill and metal polish that I learned from the YouTube video that played right after the link that you provided. I trimmed the gasket, no luck with that either. Finally I had saved all the needles from last seasons rebuild and found two old ones that were in the best shape and installed those. That was it. The carbs didn't leak anymore after that. Thanks so much for the very thorough response.

Now the engine runs great, no leaks. Of course now all of a sudden the tach is pinned at 7k rpms!! I probably knocked a wire loose. Ah the pleasures of boat ownership. Thanks again

 

[fmt2bx]

Hey, You are welcome and glad it all worked out . Yup, I am with you about boat ownership. Battling ignition issues right now. Not fun at all:frusty: