Shuboxlover 481 #1 Posted April 29, 2014 Is there a sure fire way to tell if the rear valve seat is loose without taking the head off? Pretty sure it's the seat, It runs, but runs rough and smells gassy....when it's running I pull the front plug wire and the whole thing instantly dies. Pretty bummed....I wish it would have been a good running tractor, but i guess it'll be up for parts if it's the valve seat. Any ideas??? Thanks Share this post Link to post Share on other sites
sorekiwi 761 #2 Posted April 29, 2014 I've only looked at 2 Onans with bad seats, but in both cases it was obvious the seat was bad from looking through the port. I bought a tractor that was running on just one cylinder and just assumed the seat was loose. That one turned out to have a broken rod. Share this post Link to post Share on other sites
shorts 182 #3 Posted April 29, 2014 You need to take it apart and find out what's going on before you damage it any more or destroy it to where it's not repairable Share this post Link to post Share on other sites
ericj 1,579 #4 Posted May 2, 2014 pull the intake and exhaust and spin it over by hand till valve opens up and the take screw driver and push against the seat you should br able to see what is the seat, and see if it moves. also a compression test, run a compression test if it's zero its probably a rod if it is low then it might be a seat. i have a P216 that has low compression on both cylinders but you can tell with plugs out that the piston is moving up and down and the valve seats appear to be good. so next step is for me to pull the heads and check it out further but just didn't get there yet. i replaced the motor on the tractor and put the bad motor on the self till i have time hahahaha eric j Share this post Link to post Share on other sites
