Carbs leaking fuel from air intake and top plate???

[off2wildblue]

I had this problem a couple months ago and had the qualified service tech. fix the boat. He said he ran it and it worked fine. Now I go to take the boat out and it has the original problem again. He said it is the Ethanol in the gas and the Stabil I used does't help with this.

Yamaha 1999 C60 with three 6H210 carbs.

Symptoms:
Start, idles and goes into gear and then it dies. Fuel leaking out the top of the carbs when ball is pumped and now on its own. Also fuel will pour out the intakes which I would also say describe as the area behind the silencer that has the butterfly flaps on them.

Service guy says that I need another carb rebuild because the pilot valves must have swelled or something and now it won't shut off gas at the bowl causing it to basically flood itself.

Corrective actions:

I bought a rebuild kit, a Seloc service manual and rebuilt all three carbs.

Old carb parts I replaced still look new...surprise!

Two issues with the carb rebuilds. One is the Yamaha kit came with O-rings and the small one looked larger than the original on the valve seat. I installed it on the valve seat but the valve seat doesn't tighten all the way down to the carb body now. Is this right or should I have used a different O-ring not with the kit? That O-ring could have been used to replaced the one at the bowl drain screw.

Also, I had one piece not used in the kit. It looks like a very small T shaped plug. What is that for? I didn't see one on the tear down or read about it in the book?

I put everything back together and still have these issues except now it won't even idle. Starts but won't run at all now and gas just pours out the carbs intakes. Could it be the fuel pump? I have replaced it four times since I got it 5 years ago. The problem with all the others were lack of fuel passing through not too much.

Lastly, when I measured the bowl I held it upside down and measured it. I bend the copper looking tab holding the pilot valve to adjust the bowl height and it should be parallel and within 12-16 mm...right?

This problem has ruined our yearly vacation trip and this weekend. Since I don't normally get weekends off it is a big deal.

Please help, I can't afford to pay out another $400 to the mechanic.

Thanks a bunch,

SAM

 

[rodbolt]

Re: Carbs leaking fuel from air intake and top plate???

the little oring usually is not included in the kit, dunno why but its not.
you most likly used the oring for the bowl drain under the needle seat.
wont work.
leaking carbs are a sign of incorrect float setting,stuck inlet needles or debris on the needle seat.
dont care ,if you rebuild the carb at breakfast.introduce debris at lunch. guess whats for dinner.
clean fresh fuel constantly is a MUST.

 

[off2wildblue]

Re: Carbs leaking fuel from air intake and top plate???

Rodbolt,

I think you're right about the O-ring. I will have to order a new set of the valve seat O-rings. Do people do this every time they buy a Yamaha kit?

When I install my float with the old O-ring and really even the incorrect one, the float measures low and I really have to bend that tab down in order to raise the float in the upside down position. Is this normal? Also, should the float end up looking horizontal to the carb body when held upside down (during adjustment)?

Lastly, if the bowl is "too low" during setting what symptom would the motor have?


Thanks,

SAM

 

[rodbolt]

Re: Carbs leaking fuel from air intake and top plate???

with the carb body upside down the float should be horizontal to the gasket surface.
yes if the valve seats are removed its best to replace the oring.
if float level is high it can flood,if low it can run lean.

 

[off2wildblue]

Re: Carbs leaking fuel from air intake and top plate???

Ok, that makes sense to me. When I rebuilt the carbs last night I did not adjust the float. If anything I thought they were too low. I am taking them all apart and re-dipping and rebuilding them again. I will also use another fuel source. Problem is I can't find one of those O-rings.

When looking at the old valve stems it looks like one is discolored about halfway up the threads. Maybe the mechanic forgot to install that O-ring. Hence, one carb flooding of the three.

If this was the case would it run okay long enough for a test drive and then go to hell later. Also, my gas source is questionable. At least now it is. I saw some garbage in it. However, prior to bringing it to the mechanic I emptied the tank and rinsed with muriatic acid and water combo and cleaned it out.

I am not sure what to do about the tank issue. It is a 15 ft flats boat (Back Country) and the tank is enclosed in the hull. I am going to post a question on that issue also.

Thanks again,

SAM

 

[rodbolt]

Re: Carbs leaking fuel from air intake and top plate???

sometimes the oring stays in the body. look for it.
if its not there then yes it can leak.
if its still flooding FIX it BEFORE taking it out.

 

[off2wildblue]

Re: Carbs leaking fuel from air intake and top plate???

Thanks,

So do you know where or what this is for? The only part left over. Maybe it was put in there instead of my O-rings of my valve stem.

SAM

 

[off2wildblue]

Re: Carbs leaking fuel from air intake and top plate???

I still don't know what that part was for but I got it running good with a different gas source and recleaning all three carbs. Now for the gas tank cleaning

SAM

 

[rodbolt]

Re: Carbs leaking fuel from air intake and top plate???

you left the cap off one of the needle valves.
thats what that part is.

 

[off2wildblue]

Re: Carbs leaking fuel from air intake and top plate???

Well, you are correct only I didn't put any of them on. I had no idea where they went. I did adjust the float to level and everything works great. Do you think it will cause any problems? I can't imagine it would.

SAM

 

[rodbolt]

Re: Carbs leaking fuel from air intake and top plate???

yes it will.
you simply CANNOT set the flots correctly without that cap in place,
you had to have seriously bent the tang.
out of the box if the needles are assembled correctly its rare to have to bend the float tangs.
take it apart and fix it correctly.