Tecumseh carburetor main jet leaking gas

[sciphi]

The carburetor on the Tecumseh HS-40 engine on my early 1970's Ariens snowblower got rebuilt today. No welch plugs, but new seals and jets all around, along with a new float needle.

The problem is that the new main jet is leaking a trickle of gas down the adjustable mixture screw. IIRC the old main jet also had this problem. The adjustable part is sealed with a little O-ring and a brass washer over the O-ring.

Does this sound more like a problem with the O-ring, or an issue with the new main jet?

 

[Merkava_4]

Is that the main mixture needle on the bottom of the float bowel ?

You might need to get a Viton O-ring.

Is this your carb in the link below ?

LINK

 

[bubbatime]

Brand new in the box carburetor for $15 shipped. Don't even bother rebuilding, and rebuilding again, old carburetors when you can get a brand new one for $15.

http://www.ebay.com/itm/Tecumseh-Carburetor-Carb-631918-HS40-Engines-Motor-615-No-Gasket-/361435761953?hash=item5427400d21:g:11MAAOSwVL1WBAcO

 

[sciphi]

Originally Posted By: bubbatime
Brand new in the box carburetor for $15 shipped. Don't even bother rebuilding, and rebuilding again, old carburetors when you can get a brand new one for $15.

http://www.ebay.com/itm/Tecumseh-Carburetor-Carb-631918-HS40-Engines-Motor-615-No-Gasket-/361435761953?hash=item5427400d21:g:11MAAOSwVL1WBAcO


It's a 613914 carb, not a -918. That particular carb is unobtanium for a cheap direct replacement. So rebuilding is the order of the day.

Originally Posted By: Merkava_4
Is that the main mixture needle on the bottom of the float bowel ?

You might need to get a Viton O-ring.

Is this your carb in the link below ?

LINK


It's part #40 in the diagram that I suspect is leaking. O-rings are cheap, I'll try that first.

 

[PhilsSmallEngine]

Bubba pointed you to the correct carburetor. It isn't unobtanium anymore. A lot of parts from Tecumseh are being replicated by Rotary. You have to reuse some pieces because the build quality on some of the accessory parts are sketchy at best. I don't waste time with Tecumseh carbs anymore since the Rotary products are so cheap. With minimal effort, any revision changes can be converted to work with the original components.

 

[yeehaw1960]

Just go to the auto parts store and get an o-ring that's about the right size to replace the original rubber. 49 cents at the most.

 

[sciphi]

Originally Posted By: PhilsSmallEngine
Bubba pointed you to the correct carburetor. It isn't unobtanium anymore. A lot of parts from Tecumseh are being replicated by Rotary. You have to reuse some pieces because the build quality on some of the accessory parts are sketchy at best. I don't waste time with Tecumseh carbs anymore since the Rotary products are so cheap. With minimal effort, any revision changes can be converted to work with the original components.


The rebuild kit I used was a Rotary kit. It seemed to be of decent quality, although the supplied O-ring for sealing the main jet looks like it was off by a hair. Or I installed the wrong O-ring in that location. Whatever, the kit was $8. Spending another $2-3 on an O-ring to make it work correctly isn't the end of the world.

And, thanks for pointing out that Rotary is continuing to support these old Tecumseh engines!

 

[sciphi]

Hopefully final update: The O-ring that was in that location was rattling around on the threaded needle of the jet. A slightly smaller internal diameter Viton O-ring was installed onto the needle. That seems to have stopped the leak. Here's hoping it lasts the season (and longer)!

 

[bmwpowere36m3]

I just rebuilt the carb on a HS50 (Ariens blower). I bought my parts from PSEP and got a Tecumseh carb rebuild kit (which was the same price as the "aftermarket" kits they were selling). Hopefully the new o-ring works out for you.

FYI, the Tecumseh o-ring fits snugly to the threaded portion of the main needle.

 

[sciphi]

I took another whack at this today.

The paper gasket sealing the jet to the bottom of the bowl wasn't sized correctly. So gasoline was pouring out of the gaps. This was discovered by removing the bowl and jet, taking the assembly to a dark room, and shining a flashlight on the inside of the bowl. The light coming through indicated the gaps. Another new o-ring sealed this up.

I'm still getting a tiny amount of gas leaking down the adjustment needle. It looks like a hair smaller o-ring will be needed. At least it's narrowed down.

 

[super20dan]

replace the fuel bowl