Briggs and Statton Backfires through carb

[Southern Comfort]

I have pressed it back in and put Loctite on the guide, but I don't feel fuss warm about that. I could take it to a machine shop, but they would probably charge almost as much as a new head. I saw online a guy that said he welded his in I'm not that good of a welder that I would attempt that. Still open for suggestions. I might put it together just to check the running and if everything works ok go ahead and get a new head. This lawn tractor is 18 yrs. old.

 

[Southern Comfort]

Loctite needs some space to work. If the guide fits the hole with with no space between the guide and the head when the guide is pressed in the Loctite will just be wiped off. You could file a groove for the Loctite in the guide and then press the guide in. The groove needs to be only a few thousandths deep. The green (#609? I forget) Loctite for cylindrical parts loses its hold completely at about 450 degrees F. It does start to weaken at about 400 degrees.
Eric

Yes, I tried the Loctite and it just wipes off. I wish I had a way to put a slight knurl on it that would slightly expand it.

 

[SPYDERLK]

Yes, I tried the Loctite and it just wipes off. I wish I had a way to put a slight knurl on it that would slightly expand it.

A knurl would result in high spots that are sharp. These would file the metal the guide gets pressed into. Cutting a very shallow spiral in the guide on a lathe will guarantee success. You will need to identify the portion of the guide that will be fully enclosed in the head and have a machine shop cut a thread solely within that portion. -- I have a lathe and did this on mine. As I recall I used a 0.040" parting tool and cut a ~4 thread/inch flat bottomed spiral about 0.002" deep. I turned the lathe by hand to have good limit control. Assembled with loctite and no more problem.

Good luck!

 

[Southern Comfort]

The Knurl is the way to go.

 

[BleedingOrange]

Would a heavy duty snap punch work, once you get everything back into it,s proper place ?

 

[SPYDERLK]

Would a heavy duty snap punch work, once you get everything back into it,s proper place ?

Im not sure that the guides are ductile. They may be cast iron.

 

[Southern Comfort]

There steel

 

[SPYDERLK]

There steel

Could be, but valves are definitely steel, and steel on steel is not a good sliding bearing combination. Thats why I think the guides are cast iron.

 

[Southern Comfort]

Could be, but valves are definitely steel, and steel on steel is not a good sliding bearing combination. Thats why I think the guides are cast iron.

I agree

 

[Willman]

You can put grooves in the guide with a demel tool, use a high temperature loctite product making sure all is perfectly clean
Also if you have access from the outside you can drill & tap for a set screw