ibskot 37 #1 Posted November 29, 2013 So, tomorrow I will be doing an oil change, tranny oil change, air filter and spark plug change. After running a few minutes it seems like it might be missing and backfires when you shut it off. Any thoughts? Suggestions? Share this post Link to post Share on other sites
Anglo Traction 759 #2 Posted November 29, 2013 Maybe also worth giving the Carb a Birthday at the same time. Share this post Link to post Share on other sites
ibskot 37 #3 Posted November 29, 2013 Anglo Traction, carb needs a "birthday"? I don't know what you mean? Share this post Link to post Share on other sites
squonk 39,123 #4 Posted November 29, 2013 I think he means cleaning out the carb by stripping it down o it's birthday suit. Share this post Link to post Share on other sites
ibskot 37 #5 Posted November 29, 2013 I guess I am a doofus. Thanks. Share this post Link to post Share on other sites
953 nut 52,162 #6 Posted November 30, 2013 (edited) I guess I am a doofus. Thanks. You aren't a doofus, just don't speak British slang. You may want to get a spray can of Seafoam and spray it into the carb while the engine is running, use a liberal amount. This should decarbon the combustion chamber and reduce the carbon hot spots that cause the backfire. Good luck and keep us posted. Edited November 30, 2013 by 953 nut Share this post Link to post Share on other sites
TT-(Moderator) 1,129 #7 Posted November 30, 2013 Single cylinder Kohler or Onan twin? Share this post Link to post Share on other sites
ibskot 37 #8 Posted November 30, 2013 Kohler. Magnum. Share this post Link to post Share on other sites
TT-(Moderator) 1,129 #9 Posted November 30, 2013 Do you know the history of the engine? How long since the valve clearance was checked / adjusted. Has it ever been decarboned? Does the carburetor have adjustable mixture screws? If it has the original canister muffler, they are infamous for causing a minor explosion when the engine is shut off. There have been discussions about the proper throttle position, etc. when stopping the engine but there are many variables. The best thing I know to do is to let the engine idle for a few minutes before turning it off. While the engine is coming to a stop (after the spark is killed) the muffler fills with combustible "air" and a hot carbon spark or the red hot baffles can ignite it. Share this post Link to post Share on other sites
ibskot 37 #10 Posted November 30, 2013 I have no clue as to the history. So, after use, let it idle for a few...I can do that. Regarding the other things, I never heard of decarboning an engine. I assume there is a thread on how to do that and adjust valve (s)? Share this post Link to post Share on other sites
TT-(Moderator) 1,129 #11 Posted November 30, 2013 Those procedures can be found in the service manual. Follow this link: http://www.wheelhorseforum.com/files/file/29-engine-kohler-magnum-m-8-m16-sm-tp-2203-apdf/ Share this post Link to post Share on other sites
ibskot 37 #12 Posted November 30, 2013 Thanks. I'll have to wait till I get to a computer. I am on my phone and it won't open. Share this post Link to post Share on other sites
boovuc 1,090 #13 Posted November 30, 2013 TT was spot on asking you what engine you have! In the WH manual for Magnum powered tractors, they recommend idling it down to cool it off first then when you kill the ignition, turn the throttle up a quarter to a half as it quits. It will not backfire doing this. Oh and my 310-8 will backfire every time I shut it off if I don't give it a half throttle of gas as I turn the key off. Don't be too concerned about that backfire. Fix the miss! Share this post Link to post Share on other sites
ibskot 37 #14 Posted November 30, 2013 As ya'll might have surmised, I am not a gear head. I can do"xyz" if I am told to do it. What is missing if it's missing? Sorry to sound like a nut. Share this post Link to post Share on other sites
boovuc 1,090 #15 Posted November 30, 2013 Nothing is missing. The "engine is missing". (Sorry for my slang). You used the term, and I quote; "after running a few minutes it seems like it might be missing and backfires when you shut it off". I simply wanted you to not stress out about the backfiring. Magnums do that. Just fix the miss in the engine. (Carb cleaning, new plugs, new gas filter, etc etc). You know, Ibskot.......It's going to be OK! Thanksgiving is over. Christmas will come and go. You'll find the gifts you need to buy everyone! The bills will get paid by June of 2014 and everyone will be happy! And you'll get your horse running like a champ! You seem like your maybe a little stressed! I know I am so I'm heading to camp tomorrow. Monday is deer season! (This translates to watching movies, drinking beer, smoking cigars, eating bad things and falling asleep under a tree). Hopefully I won't see a deer! Dropping one ruins everything then I'll be stressed again! Good Luck! 1 Share this post Link to post Share on other sites
ibskot 37 #16 Posted November 30, 2013 Boovac, I meant what does missing mean.... not what is absent. I appreciate your encouragement though. Enjoy the woods! Share this post Link to post Share on other sites
leeave96 487 #17 Posted November 30, 2013 If the engine is missing, the engine is not firing on every revolution - you can hear it. The 16 hp single cylinder engines can vibrate a lot, especially at lower RPM's - normal. If it's the vibration that you are feeling/hearing, you're ok. Someone correct me if I'm wrong, but with the Magnum engines, the ignition is solid state, so no points to time the engine - so the electronic ignition should take care of any timing issues that might otherwise cause a mis or backfire. You carb might not be adjustable, at least on the high speed jet if it is a Walboro. My 314-8 with 14hp Magnum will backfire when I turn it off at high throttle and hot from working it and turning off at high RPM's. Soooo - my guess is that you have noticeable vibration, not a miss, you are turning off the engine without idling down/letting the engine cool. "Not a gear head". You will be soon - and that's a very fun/good thing.... 416-8 with Kohler Magnum is IMHO one of the best tractors Wheelhorse ever made. Good luck, Bill 1 Share this post Link to post Share on other sites
Anglo Traction 759 #18 Posted November 30, 2013 Anglo Traction, carb needs a "birthday"? I don't know what you mean? Sorry ibskot , I get a little complacent with jargon, not realising some maybe unfamiliar. Yes , as Mike (Squonk) explained , maybe give the Carb a clean as well. 1 Share this post Link to post Share on other sites
ibskot 37 #19 Posted November 30, 2013 Update...I got so far as to buy oil, tranny oil, plug, and air filter. Got the air filter installed. Came inside since I had been outside a while and my toes are numb. I got my lights working on my 312-8! Do ya'll buy replacements at auto parts store? Share this post Link to post Share on other sites
ibskot 37 #20 Posted December 2, 2013 Welp, I changed the plug with proper gapping, air filter, new oil, new tranny oil, and I sprayed Seafoam decarbonizer for a bit. It blowed smoke like a semi truck. Anyway, can ya'll take a listen and tell me if this sounds good? It sounds different then the 312 and takes a good bit of time to warm up. Anyway, thanks in advance. Sorry for the photobucket link but I don't know how else to do it. Share this post Link to post Share on other sites
eb in oregon 28 #21 Posted December 2, 2013 I guess I am a doofus. Thanks. You aren't a doofus, just don't speak British slang. You may want to get a spray can of Seafoam and spray it into the carb while the engine is running, use a liberal amount. This should decarbon the combustion chamber and reduce the carbon hot spots that cause the backfire. Good luck and keep us posted. I've heard good things about "Seafoam," but I used to do the same thing with 1/2 cup of ATF (automatic transmission fluid) followed by a quart of tap water. The crap that came out of the tail pipe of anything subjected to such a thing was memorable. And it always made those combustion chambers as clean as they could get without bead blasting. You have to keep the rpm's up a little, and pour slowly into the carburetor, but it does the job. Share this post Link to post Share on other sites
boovuc 1,090 #22 Posted December 4, 2013 That doesn't sound OK. It still is "missing". (Not firing on every stroke that it should). Trying to pin it down is tougher. You have a new plug so that is good. The ignition is electronic so we don't have to look into that. Seafoam can only do so much if the carb is really gelled up. If you didn't completely clean your carburetor, that is where I would start next. The 310 didn't come with an in-line fuel filter but there is a mesh screen on the gas valve coming out of the gasoline tank. You may want to make sure your getting plenty of gasoline from the tank and that it and your fuel lines aren't plugged up. Another thing to do is place that tractor in a very dark location at night and fire it up. Look for sparking or wires arching indication a bad wire that is grounding out and causing it to run poorly. Share this post Link to post Share on other sites
KATO 115 #23 Posted December 4, 2013 (edited) Sounds like a sticking or burnt intake valve to me as the "miss" seems quieter when you close throttle back down.I would investigate weather or not it is a backfire out of the carb as thats what it sounds like to me. If so you need to pull the head and look at your valves. :tools-wrench: Or they may just need adjustment?? Edited December 4, 2013 by KATO Share this post Link to post Share on other sites
ibskot 37 #24 Posted December 4, 2013 That doesn't sound OK. It still is "missing". (Not firing on every stroke that it should). Trying to pin it down is tougher. You have a new plug so that is good. The ignition is electronic so we don't have to look into that. Seafoam can only do so much if the carb is really gelled up. If you didn't completely clean your carburetor, that is where I would start next. The 310 didn't come with an in-line fuel filter but there is a mesh screen on the gas valve coming out of the gasoline tank. You may want to make sure your getting plenty of gasoline from the tank and that it and your fuel lines aren't plugged up. Another thing to do is place that tractor in a very dark location at night and fire it up. Look for sparking or wires arching indication a bad wire that is grounding out and causing it to run poorly. This I can do. Should i add an in line fuel filter? Share this post Link to post Share on other sites
ibskot 37 #25 Posted December 4, 2013 Sounds like a sticking or burnt intake valve to me as the "miss" seems quieter when you close throttle back down.I would investigate weather or not it is a backfire out of the carb as thats what it sounds like to me. If so you need to pull the head and look at your valves. :tools-wrench: Or they may just need adjustment?? Honestly, how hard is this? And what would I be looking for? How can you tell where the backfire comes from and still keep your hearing? It doesn't backfire if I let it idle a minute or 2 before I shut it off. Share this post Link to post Share on other sites