# TECUMSEH HM80-155128E carb leak



## mikeleti (Jan 24, 2009)

Just picked up an Ariens 1978 vintage in remarkable condition. The only visible problem is gas leaking from the bore out the choke area and runs rich at idle. Engine off it leaks badly with the fuel shut off open.

Cleaned up carb and replaced needle and seat and idle screws. Same problem.

After reading many posts and reading manuals things seemed to point to a vent problem,I double checked for anything plugged but found nothing.

After another few hours reading and thinking I decided to pull off the primer bulb hose and try again THE FLOODING STOPPED, the primer port vents the fuel bowl with the hose off and everything is OK. The primer is non vented type screwed into the cover.with only the hose going directly to the hose barb on the body.

There are no other vents that I can find. I am thinking that maybe there should be a check valve in the primer hose that would allow the line to vent when not priming.

ANY IDEAS????
Please help.
Thanks,
Mike


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## 30yearTech (Sep 14, 2006)

Look for a welch plug on the bottom of the carburetor near the inlet needle outlet. This should cover the external vent, which is usually just a small hole on the side of the carburetor. I don't think your carburetor vent's through the primer or there would have to be an opening in the primer bulb to let air in.


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## mikeleti (Jan 24, 2009)

Already took out the plug, nothing but a deep cavity and the one barb hole for the primer.I looked with a magnifying glass too.
Have you ever seen such a thing as a vent in the primer line? I think that might do it.
I may try putting a small tee in the primer line and see what happens. I could restrict the open end of the tee if necessary.


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## mak6 (Jan 10, 2009)

It's a tiny hole about .020" diameter on the side of the carburator approximately 1/2 inch above the idle mixture screw. I cleared it by removing the float bowl and spraying carb cleaner into the vent hole by the expansion plug until the blockage opened.


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## mikeleti (Jan 24, 2009)

*Mak6 your the MAN!!!!!*

WOW I'll say it's small I had to use the needle clip to clear it, and that barely fit. 
I was beginning to think that someone forgot to drill the hole and this thing must have been leaking from day one. 

I bet there are a lot of carbs in the trash because of this tiny little hole. 

That should do it,too late to try it now, I'll reassemble tomorrow.

Thanks again,
Mike


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## 30yearTech (Sep 14, 2006)

I guess maybe you just needed a bigger magnifying glass...


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## Lawnmowertech (Nov 12, 2008)

mak6 said:


> It's a tiny hole about .020" diameter on the side of the carburator approximately 1/2 inch above the idle mixture screw. I cleared it by removing the float bowl and spraying carb cleaner into the vent hole by the expansion plug until the blockage opened.


mak6 how long you been working on Tecumsehs ? i can tell its been a long time good post alot of times that vent gets overlooked


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## SEHead (Jan 31, 2009)

My buddy told me he uses those tiny little flosser tools that dentists use to clean that little bugger when he is working on these carbs.


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## Rpeters123 (Oct 19, 2005)

*Need pictures or drawings to help us all learn more.*

:thumbsup: Maybe someone can post helpful pics of this .020 vent hole for us. If anyone else has hard to find carb holes,jets or vents those pics will help too. Example: on the float bowl retaining 7/16 bolt high speed adjustable screw main jet the small mid speed tiny hole in the high speed screw threads on a Tech. 6,7 , 8 HP snowblower. Thanks great site learn new info every visit.


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