Fuel leaking out side of carb

[Jtom7]

Finally fished with rebuild of 1988 85hp force and it starts and runs well in driveway but when I got to river and started it I saw fuel leaking out a screw on the side of the carb. Not sure what the screw is called but its a brass colored screw with a hole in the center of it and fuel keeps pushing out of it. This screw is located in middle just above the bowl on the side where the fuel lines run to each carb above and below it. I noticed it leak a little when I tilted the motor up in driveway but then it leaked continuously while it ran in river. Can anyone tell me what this screw does and why they have a hole in them and why mine is leaking? Stuck float or something?? Thanks for any and all input.

 

[pnwboat]

Re: Fuel leaking out side of carb

Are you sure it's a screw? Each carburetor has a brass fuel bowl vent insert that has a metered hole in it. If gas is leaking out of the fuel bowl vent (see circle in picture below), it's because there is too much gas in the fuel bowl due to:




1. Needle valve bad.
2. Debris stuck between the needle valve and seat preventing it from closing. All it takes is something not much bigger than a strand of hair to do this. Best way to prevent this is to install an in line fuel filter between the fuel pump and carburetors.
3. Fuel float is set too high.
4. Fuel float has become "fuel logged" due to age and is not as buoyant. This is especially true if you have the black styrofoam type of floats. You can compensate by setting the float to close about 1/16 - 1/8th of an inch lower than factory specs. Final setting depends on how fuel logged the floats are so you may have a little trial and error getting them set right. Best thing to do is to find a set of the plastic floats that have a metal adjusting tab that rides against the needle valve. Most of the new replacement plastic floats have a plastic tab and you cannot adjust the float level.

If this is not where it's leaking from, then a picture would help.

 

[Jtom7]

Re: Fuel leaking out side of carb

That is the thing I was talking about but on this carb it has a slit through it so it can be turned with a flat head screw driver. The float is made of tin I think and didn't appear logged to me when I put new gaskets in it. I tried to copy and paste a pic but it won't let me with my iphone. How do u post a pic thru a phone rather than a computer? I guess I can check a little closer tomorrow to see if your ideas work. Weird it didn't do this until I got to the river cuz I rabbit in driveway with water muffs and no probs. thanks for reply.

 

[Jtom7]

Re: Fuel leaking out side of carb

Lol tried it in driveway not rabbit. Stupid auto correct.

 

[pnwboat]

Re: Fuel leaking out side of carb

Sounds like you just have either a bad needle valve, float adjusted too high or crud preventing the needle valve from closing. Which ever it is, it should be an easy fix.

 

[jerryjerry05]

Re: Fuel leaking out side of carb

That's not a screw. That is a jet.
I believe???It's for the low speed side of the carb.
Fuel leaking from there is a float,needle/seat problem.

 

[Jtom7]

Re: Fuel leaking out side of carb

Float not logged, doesn't seem set too high and needle seems clean. Cleaned it anyways with help of machine shop that honed my power head (he's a great helpful guy) and still leaking so he suggested using a good carb off my blown motor which I did and viola it's no longer leaking and was running great but the vibration caused the idle screw to back out a bit and now I have idle problems. It just never ends. I got a nut put on it to stop it from turning out (should have been one already but this is a motor i bought so who knows what they were thinking). was trying to set the cam so the line matched that ecentric screw but to stay idling it has to be pushed passed that point. Taking a break at the moment and will attack it again in a bit. Someday I'll have better understanding of all this stuff.

 

[pnwboat]

Re: Fuel leaking out side of carb

Well at least you no longer have a leak. The idle adjustment screw on the tower shaft comes from the factory with a locknut. Sounds like one of the previous owner must have lost it.

That's one of the problems with some of these older motors. They've been through so many previous owners, sometimes you run into all kinds of crazy stuff that's been done to them.

 

[Jtom7]

Re: Fuel leaking out side of carb

When these force motors are idling should these carb butterflies be closed and timing towers not very advanced? I'm trying to figure out where the idle screw should be at cuz it seems to want to run with tower advanced a bit farther and carbs being opened a bit more

 

[pnwboat]

Re: Fuel leaking out side of carb

Just for clarification. The idle screw you mentioned in post #7. Are you referring to the screw on the carburetor? or the screw on the tower shaft. The screw on the carburetor is the idle mixture screw. It should be set to 1 to 1 1/2 turns out from lightly seated. Depends on each individual motor. You do not adjust this screw to change the idle speed. This is for the idle mixture. It should have a spring which puts tension on the screw to prevent it from moving......unless the screw is screwed out so far that the tension is very light.

The idle speed is set with this screw and it has a lock nut to prevent it from moving. See red arrow below.

 

[jerryjerry05]

Re: Fuel leaking out side of carb

The 88/85 has the air screw in the front top of the carb.Unless the carbs have been changed.
Te factory suggested that the air screw be set at 1 turn out(88/125) and left there.I do that on mine and haven't had a bit of trouble.
The 125's have the screw on the side.
Top thread in this forum,there is a thread from FrankA called a linc and sinc.
This will help set up the carbs.
The "towershaft is for adjusting the idle and used in acceleration only.
The timing is adjusted by undoing the linkage at the top of the towershaft and moving the draglink.
The butterflies will be closed or close to it when setting up.But might move after the idle is moved up.