Leaking Carburetor

[Joe Flanagan]

I solved the overflowing oil filter canister issue. Young Ed hit the nail on the head when he suggested the gasket might not be right. He was right. It wasn't right. I bought two filter inserts from Roberts and they came with new gaskets. I installed one and thought it was a good fit but I didn't look closely enough. It turns out they were too wide and would pinch rather than seat. So i reduced their width with a razor blade and tightened the lid down and that was the end of that little problem.

My carburetor does leak, though. It's coming from the lowermost section of the carb. There is the main body, a small intermediate piece, and then the lower section. There are two gaskets close together here and it's leaking either from the top of the intermediate piece or from the bottom of it. Here are some pictures. I used a red WD40 nozzle to point out where the leak is coming from:

I rebuilt the carb about seven years ago, then sealed it up in a plastic bag and stored it. I took it apart again recently before installing it, just to double check. Everything looked good. All nuts and bolts are tight and the gaskets are new. I plan to remove it soon and take it apart again, but wanted to see if you guys had any ideas. Engine starts nicely but will only run for a few seconds before dying out. I shoot starter fluid down the throat and it will start but as soon as the fluid has been burned, it dies out. The accelerator pump definitely works because I have managed to pull back on the linkage and get it to race. It just seems like it can't feed itself gasoline and idle normally.

[Young Ed]

Joe the kits come with multiple gaskets that are close make sure the holes all line up and that the diameter of the middle throat matches between the gasket and the carb pieces. Also take something very flat like glass etc and sand those pieces to make sure they are flat. Are you sure the carb is leaking there and not running down the outside from further up?

[Don Coatney]

Have you checked your float height?

[greg g]

raw gas at the trottle plate pivot idicates an incorrect (too high) float setting. or a needle and seat not closing. this allows the float bowl to over fill and overflow down the carb throat.

[Joe Flanagan]

I set the float height at 1/64 inch below the rim of the bowl as per the manual. I think probably I should double check, though and also check the gaskets as Ed says.

[Young Ed]

1/64th? that seems high. I think its 3/64ths. And I think its better to set it another 64th or 2 lower then that.

[Fireball]

Still, none of those tiny leaks prevent your engine running, so the fuel gets blocked somewhere on it's way from bowl to intake.

[daddyo23]

I had a problem like that and it was the gasket in between the bottom and middle section. Like Ed said there are 2 or 3 gaskets in the kit and they are very close in size. If I remember right you use the one that just barely covers the area. When tightened down it seals correctly. The one I had covered everything but when tightend spread out a little too much and had a resulting leak, more of air than fuel, but it would barely idle and seemed like it wasn't getting gas. Changed gaskets and it ran fine. Good luck.

[Joe Flanagan]

Getting ready to remove the carb right now. Whatever they suggested in the manual is how I adjusted the float, whether it was 1/64 or 3/64, I can't recall. First thing I'm going to look for is gas in the float. Then will double check float height, then disassemble and inspect gaskets.

[P-12 Tommy]

Joe, I'm thinking 5/64

[JIPJOBXX]

This sound a little mickey mouse but why don't just spread some permatex on that sealing area and tighten it down. My top gasket is shot but I managed to save it till I get another one but I just spread some permatex on it and the matting surface and my carberator works perfect.

[Tom Skinner]

Joe,

The Castings may be warped/bent from over tightening etc.

Take it all apart and lay them on a flat surface, use a light from behind and observe the bend or warp.

Often times a simple piece of 100 grit sandpaper on a flat surface face up.

Take the offending casting and rub it across the sandpaper until flat.

Do not sand excessive amounts off - just correct the surfaces.

Re - gasket that baby assemble with new lock washers and enjoy a leak free Carburator. Other ways involve a block of wood and beating everything back flat (not my favorite way unless I'm forced to use this method).

Take your time and observe whats making it leak. Sometimes its at the throttle shaft (worn out) re-bushing it (drill it out and install a bushing)

Good Luck!

Tom

[greg g]

A piece of window glass makes a good flat surface to put the sandpaper on.

[Joe Flanagan]

Thanks for all the suggestions. As it turns out, I had two different size flange gaskets installed. As Ed pointed out, the rebuild kit came with two gaskets with a larger hole in the middle and two with a smaller hole in the middle. I was using one of each. I went with the smaller diameter ones, which cover more area, as it seemed the larger diameter gaskets seemed like they might leak. I may have to reverse this and do the opposite, but we'll see.

Took the carb apart and examined the mating surfaces. One of them was pretty far from flat. I don't know how this could have happened but if I had to guess I'd say it was about a 64th out: High on the outer edges. I used a body working dolly with a flat surface and some sandpaper and improved it but didn't get it perfect. I don't want to sand too much and I'm hoping the gasket will seal the difference.

The manual calls for 5/64 of an inch from the rim of the float bowl to the top of the float. I rechecked it and I'm a bit lower than that (the manual says 1/64 on either side is OK). Double checked the needle and seat and they are clean.

I'll be back at it tomorrow and will let everyone know what happens.

Edited March 5, 2010 by Joe Flanagan