PB Blaster+MMO
 

Had a stuck intake valve causing my cub to back fire through the carb. I mean literal fire like almost burnt my cub up haha right. Well i took the carb off cleaned it, took the head off sprayed in some pb blaster worked the valve up and down, reassembled everything and now she is running super good. Just thought i'd share the story and bout the pb freeing up that valve.

Please place a trade ad in the for sale section and you'll have better luck finding a trade.:beerchug:

Keep an eye on it so to speak, as the problem will usually come back.
The only real fix is remove the valve, clean the stem and the guide.
It's also a great time to remove the carbon on the piston/head.
No lead gas causes the lack of lube to the stem.

Interresting.......:bigthink:
Why does Kohler want the owner to use unleaded fuel?
Page 1.5 of a Kohler service manual states Use only clean, fresh, unleaded gasoline with a octane rating of 87 or higher.
Unleaded gasoline is recomended as it leaves less combustion chamber deposits.

The lead in gasoline acts as a cushion between the valve and valve seat. Some engines needed the lead because they didn't have a harden valve or valve seat. Leaded gasoline will leave deposits in the combustion chamber and valve stem. The deposits is what causes the valve to stick....not the lack of lube.

I agree with Merk!! I remember the only negative going to unleaded was old engines needed harder valve seats.

Many people ran Amoco Ultimate before unleaded was popular. The exhaust system would last forever, an unusual situation in Pittsburgh!!

Back in the 60's we were taught that tetraethyl lead not only increased the octane but lubed the seats as well as the valve stems.
Yes, it caused lead deposits on/in the combustion chamber as well as the valves.
I have to ASSUME ( and we both know where that leads) that the no-lead requirements, required/forced the manufactures to spec their engines for no lead.
They had some choices as far as valve life, go hardened seats or change the cast iron in the block (or heads if OHV) for better durability.
We know hardened seats have always been required for propane engines because of no lead situation.
a lot of industrial engines also came with hardened seats, some were inserts some were induction process.
My experience was I didn't see as much sticky valve problems with leaded gas. but did see more deposits because of it.
I feel that the sticky exhaust problems in Kohlers are a carry over of traditional block material without the lead as lube. but what do I know as I was not a Kohler engineer when they were built.

All small engines were designed to run on unleaded fuel. A good example is a Cub Cadet Orginal. They were made early 60's.....long before unleaded fuel was the only fuel you could buy.


Interresting information on tetraethyl lead:
http://en.wikipedia.org/wiki/Tetraethyllead

I didn't see anything about tetraethyl lead being a lubricant.

Not knowing the history of the engine we can't tell what caused the problem(s).

Maybe I was thinking of the white lead I use as a lubricant on my lathe centers.
You are 100% entitled to your beliefs as I am mine.