BESTDOGEVER 218 #1 Posted April 12, 2024 A while ago I replaced the plug on my 310-8 and not being able to find a h10c I used a substitute . Shortly after it started to backfire and run on when I shut it down. I checked everything I could think of and started looking at the kill wire from the switch and found nothing. Recently I saw an article about how the single cylinder Kohler engine was really supposed to have the h10c. I made it a point to find one and switched plugs ,and checked it out. The backfire and run on cleared up right away. The used plug was clean ,no carbon or anything that might cause that. Could it be that the other plug was firing even on a weaker spark while the engine was slowing down? Anyhow I thought it might be something others may encounter. 1 Share this post Link to post Share on other sites
pfrederi 18,638 #2 Posted April 12, 2024 (edited) I gave up on Champions years ago use autolite 216 in the big blocks... Edited April 12, 2024 by pfrederi 3 1 Share this post Link to post Share on other sites
ebinmaine 72,426 #3 Posted April 13, 2024 11 hours ago, pfrederi said: I gave up on Champions years ago use autolite 216 in the big blocks... I hadn't touched a Champion in 30 until we got Kohler engines. They've been OK to us but I've had a couple that were a few years old and just wouldn't fire anymore. Swapped to a new Champion (because that's what I had on hand) and run fine. I now swap out a plug every 2 or 3 years as a matter of maintenance. I'd always had good luck with Autolite, FoMoCo, AC Delco, NGK, Bosch too. 12 hours ago, BESTDOGEVER said: made it a point to find one and switched plugs ,and checked it out. The backfire and run on cleared up right away. 12 hours ago, BESTDOGEVER said: used a substitute My first thought here is that your substitute was a hotter heat range causing detonation. Share this post Link to post Share on other sites
BESTDOGEVER 218 #4 Posted April 16, 2024 You know Eb that was one of the things I was considering along with maybe a kill wire not being securely grounded. So for about 4 bucks for the plug I don't have to tear everything apart. I had always used the H10C since new so the article got me thinking in a different direction. 1 Share this post Link to post Share on other sites
