INT.424 "pops" through intake

LAD1DER · Oct 17, 2006

SLOWREV, you nailed it. Had bent pushrods for cylinders 1 and 3. Runs like a top now. I guess I can stop browsing the tractor sales websites for a replacement.
Thanks for the advice. This is a great resource.

slowrev · Oct 17, 2006

Seen it happen before on that type of engine. Ususally due to the tractor sitting outside and the valves stick a bit. When you fire it up it bends pushrods.
The valves often come unstuck and are fine except for the bent pushrods.
I do recommend keeping it inside though

Ben

LAD1DER · Oct 20, 2006

I really don't have any way to keep it inside. How would keeping it inside an unheated shelter prevent the valves from sticking? And what can I do as a preventative measure to protect it while it is outside?

slowrev · Oct 20, 2006

Water down the stack causes the stuck valves and bent push rods. I know from friends experience.
A can over the exhaust and make sure the exhaust is tight where it goes into the manifold. Some stove cement will seal it up pretty good if loose/wobbly.
the exhaust flapper things help but will let some water down the pipe sometimes.

Just keep the rain from getting into the manifold, no problem on the intake since it is an updraft carb

Soundguy · Oct 21, 2006

I agree with slowrev... muffler or stove or chimney putty at any mufler to manifold connection where water could go down a connector sleave.. or wick in, and then a folgers can over the stack.

Soundguy

slowrev · Oct 22, 2006

And you can play catch the can when you start up without removing it

Ben

LAD1DER · Oct 22, 2006

Should I be putting a lead additive in the fuel? It occurred to me that this engine was more than likely designed for leaded fuel, and I believe the purpose of the lead was to lubricate the valves.

Soundguy · Oct 23, 2006

NO.. tetra ethyl lead was added as an anti ping/spark knock ( octane issue ).. NOT as valve lube.

Likely your unit DOES have hardened valve seats.. check your parts catalogs. Gas in the old days was 70ish octane.. that makes for preignition and spark knock.... Modern 89/93 high octane gas is -fine- in low compression engines...

Soundguy