RedPaul 50 #1 Posted June 23, 2019 Does the timing on a Kohler magnum engine advace with engine RPM? The engine on my 312-8 starts instantly and idles smooth but as it revs the exhaust note changes to a popping sound and it loses power. It acts like it is going out of time or a valve is sticking. When it starts to 'pop' you can feel a puff coming back out of the carborator with the air cleaner off. I have pulled the head and the valves are clean, move like they should, (at least when spinning by hand) and seem to seat well. This engine has run sort of strange strange since I got it about a year ago (kind of a stutter exhaust note), I just used it to pull a little wagon so was not to concerned. Now I have it up at my new house in Northern Mich to cut about 1/2 acre of flat lawn, This is the first time I have really put a load on it and there is a real lack of power, as in pretty much usless for mowing. When I got the tractor I cleaned the head, top of piston and valves and changed the fuel lines and filter, I checked the fuel shutoff valve today and the screen was kind of mucky but I cleaned it up. Any Ideas would be appreciated, Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,161 #2 Posted June 23, 2019 Can you remove the muffler easily? Give it a shake to see if there is part of a baffle loose in it which can cover the outlet and prevent the engine from reving up. Tapping it with a rubber mallet may make it rattle. The inlet pipe on the inside of the muffler is capped and holes are drilled in the sides of the tube. This is where they burn off. With the muffler off you can look down the inlet tube and see it. Garry 1 Share this post Link to post Share on other sites
RedPaul 50 #3 Posted June 23, 2019 Remove easily? probably not, but enough PB blaster, heat, busted knuckles and swearing and I will get it off. The muffler is rusted trough in a a few places so you may be on the right track. Thanks for the information. I will let you know what I find. Are replacement mufflers still available? Share this post Link to post Share on other sites
RedPaul 50 #4 Posted July 7, 2019 Excellant call on the loose baffle parts. I got the muffler off yesterday and sure einough there is a loose piece inside that looked like a cap. I could get ahold of it with a pair of needle nose pliers and managed to mangle it up pretty good but I could not get it out. I think it is misshapened enough that it will not plug anything up to bad. It runs like a champ now with no pops. Thank you much Garry Share this post Link to post Share on other sites
