My Tractor Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
172 Posts
Discussion Starter #1
I made some progress on my FF20 I got last week. It has an Onan 20hp B48G twin. I got it to fire, but it only runs on one cylinder. Come to find that the intake valve on one cylinder is rusted open. This happens to be on the cylinder with the breather cover. The hose was missing from the breather and water got into there and rusted things up pretty nice (explains the water I found in the oil). It has been sitting like this for 2 years, so says the previous owner. Does anyone have and ideas for removing this valve? If I need to replace the valve I will, but I dont want to wreck the valve guide or seat. I tried soaking this thing in kroil and applying some heat to no avail, its stuck solid. Thanks!
 

·
Registered
Joined
·
2,927 Posts
I've gotten many an engine with a stuck valve. Pull the head squirt penetrant under valve head & tapp gently with a punch squarely in the center of the valve head. Most times they move quite easily. Be sure the lifter is away from the stem when you do this. Once down, squirt more penetrant on stem on spring side, then roll engine to lift valve again. Repeat this until the valve returns on it's own while turning engine, slap head back on & crank.
BTW...if valve face & seat look crusty, just fold some emery cloth & run around under to clean them up. I've done this on some nasty looking valves & they ran for years after with no further service.
 

·
Registered
Joined
·
172 Posts
Discussion Starter #3
Thanks for the help, worked like a charm! I had to do that procedure countless times before it gave. Moves fine now, and has good compression. Great tip!
 
1 - 3 of 3 Posts
Top