Sealing welch plugs

[Tim Frank]

I "usually" use a few drops of lacquer or nail polish as an extra seal on top of the expansion from flattening the plug.

How "perfect" does this seal have to be in practice? Anyone know?

Just did a 6 HP carb up at the cottage..and didn't have anything to use as a liquid sealer. The plug is really accessible so I can do a retro-seal if there is a problem. But would you not need a fairly significant air leak past that plug to actually impact the carb performance?

 

[HighTrim]

Re: Sealing welch plugs

Ive never actually used any sealer on the welch plugs, and so far no problems.

I would imagine it would be hard to notice a small leak there and properly diagnose it. Have bought motors though with the plugs coated in 847, so someone obviously at one point thought it was leaking.

 

[Tim Frank]

Re: Sealing welch plugs

With the slight crown, even when the 'dome" is flattened, a drop of nail polish flows beautifully around the circumference and makes a really tidy sealing ring.

That said, the mfrs. don't do that (as far as i know) and I had always thought that it was so that gas wouldn't leak out. In truth, never really put any thought in...just had that picture and never questioned it.
Doing this last carb, i actually looked at what I was sealing with the welch plug AND payed attention.

No way fuel is EVER leaking out that way ....barring a major carb problem ....so I probably have wasted time on what is likely a far less critical item than I had thought.

 

[JB]

Re: Sealing welch plugs

Any pressure differential on opposite sides of the Welch plugs is too small to matter and too small to cause any leakage. The only challenge is to make sure the plug stays in there until you want to remove it.

 

[boobie]

Re: Sealing welch plugs

I've always used Gasoila sealer on them as I didn't want any air or fuel leaks.

 

[Tim Frank]

Re: Sealing welch plugs

Any pressure differential on opposite sides of the Welch plugs is too small to matter and too small to cause any leakage. The only challenge is to make sure the plug stays in there until you want to remove it.

I have 3 OEM manuals for my 3 O/Bs, from 2 different manufacturers. You'd think one of them could explain this in as simple English as JB has.
Guess that's why he gets the big bucks.
Thanks!

 

[dazk14]

Re: Sealing welch plugs

An air leak around the plug will cause a lean condition and poor running...if that's what we are talking about here.

 

[JB]

Re: Sealing welch plugs

An air leak around the plug will cause a lean condition and poor running...if that's what we are talking about here.

Sure. And peeing in the Mississippi will cause a flood.

 

[boobie]

Re: Sealing welch plugs

I was just up in Minn not to long ago and peed in the Mississippi and look what happened. LOL.

 

[JB]

Re: Sealing welch plugs

AHA!! Now we know who to blame.

 

[levi_tsk]

Re: Sealing welch plugs

lmfao JB and boobie
tim i never put any sealer on mine just make sure you get it fairly flat