Seating core/welch plugs?

sutor623

Rear Admiral
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May 23, 2011
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Hey fellas, what are you guys using to seat core plugs in carburetors? I usually take a socket about 1/2 as big around as the plug and tap em in place.

Also, what for sealant? I have set them dry with no issues. I have also heard of guys using nail polish, but I dont see how that would stay in place while coming in contact with fuel.............
 

Cat nip

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Jul 25, 2015
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My buddy who is a outboard mechanic uses a socket or extension to seat them flat and uses jet super glue for model aircraft and such and dries instantly with zip kicker. The glue is impervious to fuel of any kind and the zip kicker don't allow it to creep any farther that you want. Both can be found at a hobby shop.
 

flyingscott

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Apr 8, 2014
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Nothing, I Use a socket to set it and leave it a lone and never had a problem. If it did leak usually they only present as an air leak permatex would work fine.
 

sutor623

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Cool, thanks guys.

I am still having idling issues with the 130hp. I sprayed the calibration pockets out real good and let em soak with carb cleaner, but I have never removed the core plugs from the throttle bodies to clean the idle mixing orifices. Got some welding tip cleaners to help clean those ports out after I finally pull the core plugs. Man I will sure feel like a dummy if that fixes my hard idling issues...............
 

oldboat1

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Think it was Gomer Pyle on the old Andy Griffith show: " fer shame, fer shame...."

Welding picks should work. I use some soft wire, sometimes some monofilament line -- and carb spray. When you have the expansion plug off, I think it's good to check the fit of the needle (should be able to see it peek through the housing, if like the old carbs) -- test fit it. And when replacing the little domed plug, tap it in the middle with a 1/4" bolt or something similar -- just enough to seat it.

Hope it's the fix.
 

sutor623

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May 23, 2011
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Think it was Gomer Pyle on the old Andy Griffith show: " fer shame, fer shame...."

Welding picks should work. I use some soft wire, sometimes some monofilament line -- and carb spray. When you have the expansion plug off, I think it's good to check the fit of the needle (should be able to see it peek through the housing, if like the old carbs) -- test fit it. And when replacing the little domed expansion plug, tap it in the middle with a 1/4" bolt or something similar -- just enough to seat it.

Hope it's the fix.

Thanks buddy. I would imagine it would. This poor motor had been through hell and back with issues. When the boat was given to me it had a shot #1 cylinder, that passed the leakdown AND compression test, but failed the cylinder drop test. Would NOT start in the cold and was SSSSSSSSOOOOOOOOOOO hard to start, everytime, but did start after a little effort. Always ran great at mid throttle and WOT.

Fast forward to now, and we get backfiring at start up, then shell start and die out unless you give her about 2000rpm throttle for a minute, then drop her back and she is ready to go. Will sputter pretty often though. Even after warm she will still act this way upon starting. Will idle for a while just fine when warm, but eventually, after a few minutes will die out. Now that the 25:1 oil mix is back down to 50:1 and I still have the issues I can't blame it on double oil anymore!!!!
 

Cat nip

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Just never use any type of silicon to seal them! It cant withstand field and will cause running problems when it breaks down and plugged passages.
 

flyingscott

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Apr 8, 2014
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Silicone works fine to seal the outside of the plug you NEVER seal the inside of a welch plug. There is no sealer made that will hold up to fuel. Even the sealer that omc uses on the plug will not hold up to fuel.
 
Last edited:

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
The specific product used to seal core plugs in carbs is called: gasoila. You need to use this product as it one that actually seals against gas leaks.
 
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