bigdog46 Posted May 29, 2014 Posted May 29, 2014 I have seen several posts regarding the Kohler Command engines backfiring and dieseling upon shutdown and possible headgasket damage. I have had the same problem with mine in my Simplicity Sovereign Hydro 18. I have had the best results shutting mine down when I throttle down to idle and pull the choke all the way out and turn off the key at the same time. It does not diesel or backfire when I use this approach. It also starts easier the next time with little to no choking. Thought some of the members might want to try this with their engines.
BLT Posted May 29, 2014 Posted May 29, 2014 You can try the way the "triad" is wired, solenoid valve is first to go on and last to shut-off by sharing the engine charge circuit. When the key is turned on, the solenoid is energized thru the start and run positions of key switch. When the key is turned to off, the mag is grounded and the charge wire is disconnected from circuit but not the solenoid and as the engine loses speed, the charge voltage will drop off to "0" and close the solenoid.
Willy Posted May 29, 2014 Posted May 29, 2014 Check your idle speed,if it's to fast this can cause dieseling, let it idle a minute or to before shutting it down, that should cool it down a little.
Burntime Posted May 31, 2014 Posted May 31, 2014 No No No. You have to shut it off full speed or risk a head gasket problem on the commands. It has a fuel shut off and if not full throttle to burn the residual fuel it will backfire and it will take out a head gasket. Ask RayS about this...
DanD Posted May 31, 2014 Posted May 31, 2014 quote:Originally posted by BurntimeNo No No. You have to shut it off full speed or risk a head gasket problem on the commands. It has a fuel shut off and if not full throttle to burn the residual fuel it will backfire and it will take out a head gasket. Ask RayS about this... id="quote">id="quote">I agree. Directions right in Simplicity and Kohler manuals say to have engine running at least half throttle when you turn off the key. No problems that way. My Triad would backfire when shutting it off, too if you didn't do this. Helped my neighbor fix his Deere that he sheared the flywheel key on by not shutting down this way. His repair parts bill was only 75 cents though!
SmilinSam Posted May 31, 2014 Posted May 31, 2014 quote:Originally posted by BurntimeNo No No. You have to shut it off full speed or risk a head gasket problem on the commands. It has a fuel shut off and if not full throttle to burn the residual fuel it will backfire and it will take out a head gasket. Ask RayS about this... id="quote">id="quote">My Briggs Vanguard twins are the same way. You must shut them down at full throttle then there's no problems.
Willy Posted May 31, 2014 Posted May 31, 2014 Sorry for the bad info, I guess you can't trust an old fart with all foot draggers.
DanD Posted May 31, 2014 Posted May 31, 2014 quote:Originally posted by WillySorry for the bad info, I guess you can't trust an old fartwith all foot draggers. id="quote">id="quote">My Sovereign with the Triad backfired many times on me before I knew what was going on. Heard about it on here then saw an owners manual and then saw my neighbor shear his flywheel key so I know it's a real phenomenon. As things get newer I think they just get more complicated. Also, it really makes no sense...why does an engine where the fuel is not shut off not backfire? I haven't been able to explain the physics of it to myself to be honest.
RayS Posted May 31, 2014 Posted May 31, 2014 Dan, you make good points on this. My Command will back fire in my Prestige (vertical shaft) if not shut down according to the owners manual. It cost me $325.00 to have it fixed. My Sovereign with a 20hp Command doesn`t backfire (atleast I haven`t had it do it yet but I always shut it off according to the owners manual). Engines equipped with shut off solenoid need to be shut off at half to full throttle and the ones that do not have them can be shut off at idle. Funny thing is my Honda GX620 in my 917H has the fuel shut off solenoid and the owners manual says nothing about it at all. I can shut that motor off at idle or wide open throttle and it never backfires. I would take the Honda over the Command any day, period. It has basically the same torque, horsepower and is more efficient on gas. The carburetor is half the size as the Command and it sat all winter with ethanol gas in it without any type of fuel stabilizer either and it started right up when I needed it to this spring. Evidently Kohler should go to Japan and take a few classes:D.
maxtorman1234 Posted June 15, 2014 Posted June 15, 2014 I've heard also of all sorts of problems with the commands backfiring, dieseling ect, and have had the problems a few times myself, like said wide open is the best way to avoid problems shutting down. I usually let mine run a minute or two wide open when really hot before shutting down. I've had a CH25 that was backfiring when shutting down wide open, turned out to be dirt in the carb blocking the shut off solenoid. I'm really puzzled about the amount of people that have these problems, I have 4 Commands on my machines, a CH23 2 CH25's and a CH20 on a generator. I wouldn't think of replacing or swapping out any of them as they run perfect. Blowing snow in the winter I have put 4 hours on my Agco 1920 on a tank, which I'm happy with. Also should note that my 25's have the updated head gaskets as the old ones definitely did have problems. I'd love to find a bunch of these with blown head gaskets that people have given up on!
BLT Posted June 15, 2014 Posted June 15, 2014 If you look at wiring diagram of Sovereign with Triad, the solenoid on carb is wired in with run wire and alternator wire which means the solenoid is the last thing to close after the spark is shutoff. I wonder if that was a method to control backfiring.
CarlH Posted June 15, 2014 Posted June 15, 2014 quote:BLT: If you look at wiring diagram of Sovereign with Triad, the solenoid on carb is wired in with run wire and alternator wire which means the solenoid is the last thing to close after the spark is shutoff. I wonder if that was a method to control backfiring.id="quote">id="quote"> I would think shutting off the fuel first is better. Shutting off the fuel last leaves unburned fuel in the cylinder ready to be fired by hot spots in the combustion chamber. ?
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