How to keep carb bolt on Tecumseh Snow King engine from coming loose?

I have a snowblower with a Tecumseh Snow King engine. The main bolt on the bottom of the carb bowl (mine is a non-adj carb with only one main bolt on the bottom of the bowl) keeps coming loose with the vibration of the engine. I'm afraid to tighten it too hard because I once broke one of these carb bolts by overtightening.

Normally I'd put that blue Loctite/Threadlocker stuff on the threads of the bolt to keep it in, but this bolt has the tiny hole going through its threads for the fuel jets, so I don't want to risk getting any of the Threadlocker in that hole or in the carb bowl.

Would it work just to put a tiny bit of the threadlocker near the head of the bolt, or would that not be enough to hold it? Anyone have any ideas on how I can tighten the bolt to the max without breaking it or anything else I can do to keep the bolt tight despite the engine vibrations?

 

You can put a little star, lock washer on it. You can find them at most hardware stores. They have a number of sharp points to dig into the bolt and mating surface on the engine/carb to hold the bolt.

Also you can put a little high temp silicon around the bolt shaft just under the head of the bolt,, but back away from the end you're concerned about plugging. That will set up and hold against the vibration. If you go this route, clean the bolt and the bolt hole with a little solvent prior to assembly.

 

Does this bolt go through the bowl of the carburetor? If so a internal or external star lock washer will probably leak. You did not mention a gasket. Is there a fiber or rubber gasket under the head of the bolt? This will seal to the carburetor's bowl and works a bit like a lock washer to prevent it from vibrating loose.

 

I see now. I thought you were talking about a bolt that held the carb to the engine. Pilot is right, the carb bowl bolt is another matter. A star washer wouldn't work there, nor would the silcon.

If torqued properly that bolt shouldn't come loose without anything else on it.

 

Usually when I forget the felt washer it has an obvious leak.

 

Sounds like the bowl gasket is not contacting the bowl. Take the bowl off and replace the big rubber ring where the bowl contacts the carb. It may even be missing. If this is not making good contact, the entire bowl can tend to try to rotate while the engine is running/vibrating and work the bolt loose.

 

To answer the other questions, yes it's the bolt that goes through the bottom of the carb bowl. Once I tighten it, no leaks and it runs fine. After about 20 minutes of the engine running, it loosens though, gas begins dribbling out of the bowl a bit, and the engine starts surging (I assume from the air coming in).

I found a repair manual for it and it says the bolt should be torqued to 50. Will have to run out and buy a torque wrench and see if that fixes it. If not, will check the gasket above the bottom bowl. Thanks for the tips everyone!

 

Gasket above the bottom bowl? Are you referring to the bowl to carb gasket or the one for the bolt/jet? Is your bolt/jet gasket inside the bowl or outside? Should be outside , between bowl and head of the bolt/jet.

 

Sounds like the float bowl gasket has gotten hard and no longer has the ability to tighten up the bowl which inturn will vibrate the bowl attaching nut loose. Make sure that nut has gasket on it as well. Good luck.