slufoot733 70 #1 Posted February 4, 2011 Well, the old D-200 is running pretty good this winter but there seems to be an engine issue. After I've run the tractor, regardless of how long, when I shut it down it backfires just as the engine stops. I always move the throttle to it's slowest position, allow the engine to idea for about a minute, then turn the key to stop. Just as the crankshaft comes to a stop one cylinder backfires. About half a second later the other cylinder backfires. The old lady next says it always makes her laugh when she hears the BANG---POW! This doesn't seem to effect how the tractor runs but I don't think it's a good idea for it to do this. Anyone have any idea what's causing this? Maybe I have the carb adjusted a little too rich. Any suggestions would be appreciated. Thanks, Kevin :thumbs: Share this post Link to post Share on other sites
Coadster32 793 #2 Posted February 4, 2011 Not much to lose by leaning it out a little bit. I'd give it a shot. :banghead: Share this post Link to post Share on other sites
Jim_M 179 #3 Posted February 4, 2011 It may also be idling too fast. Share this post Link to post Share on other sites
Gerry w 2 #4 Posted February 4, 2011 Name that rig "Uncle Buck!" My Raider used to do that till someone told me it could be stuff in the muffler igniting when I switch it off. Took off the muffler and knocked it out good, placed it back on, and it doesn't do it anymore!! Share this post Link to post Share on other sites
nylyon-(Admin) 7,935 #5 Posted February 4, 2011 I call that BSS (Brown Seat Syndrome) because it scares the....... My 414 does it all the time UNLESS I let it idle for quite some time OR I shut it down at half throttle. I usually do the half throttle and it never BSS's then. Share this post Link to post Share on other sites
Sparky-(Admin) 23,228 #6 Posted February 4, 2011 None of my "K" series single cylinder Kohlers have done it but I've had two Magnum 12's and they both did it . Mike...... Share this post Link to post Share on other sites
Redbirdman 7 #7 Posted February 4, 2011 Unless the timing is off, which I greatly doubt, the burning carbon theory is probably the culprit. Don't forget, when you are shutting down with the ignition switch you are killing the spark, but the fuel is still sucking and unlike a machine that is still running you are now blowing raw fuel out as exhaust. When enough of the right mixture reaches that burning carbon ka pow! It happened to me a lot with JD 140's..It really is not a backfire but a muffler explosion. And I suspect it is more prone at idle because the fuel is leaner by the time it reaches that 'little ring of burning fire' (hmmm that would make a good song huh?) Holding the throttle at 1/2 or more might just make the mixture too rich to ignite......... That's one of the main reasons light aircraft shut down by leaning the mixture to zero. (That and to prevent unwanted startups when moving the prop if you forget to kill the mags!) But I would suggest to prove the theory, or at least to try something, shut the fuel off at the tank and let her run out. This will be the same (almost) as really leaning the mixture, causing the chamber to run hotter, hopefully burning a lotta crap in the process. Just bring the throttle up above idle as she runs out of fuel. just 2 cents................maybe, maybe not ed Share this post Link to post Share on other sites
Operator 7 #8 Posted February 4, 2011 I call that BSS (Brown Seat Syndrome) because it scares the....... My 414 does it all the time UNLESS I let it idle for quite some time OR I shut it down at half throttle. I usually do the half throttle and it never BSS's then. That is what my dealer told me to do too, shut it down at a little over idle. Unburned fuel in the mufflers he said. Rev'ed up it burns off more. Share this post Link to post Share on other sites