WheelHorseSteve 48 #1 Posted July 17, 2013 (edited) Hello -- My friend has a 16HP Kohler vertical shaft on his Craftsman lawn tractor that has started to do something odd that I'm hoping the experts here on Red Square have some ideas on. Here's what he described: On start up, while cranking, it is backfiring (through the exhaust) while the throttle is medium to high. It is not catching. He can eventually get it to catch / run if he starts it at idle, and the engine runs fair to okay. The other odd phenomena which I'm not certain is related here -- when the gas level in the tank gets to the half-way point it starts running poorly... so he tops it off frequently to avoid that. Both of these problems are relatively new, and the machine is 13 years old w/ as many mowing seasons on it (~750 hrs). What do you think might be the problem here? RE: the backfiring I suggested some sort of valve problem / dirty head, but the fuel level bit is odd... perhaps it's totally separate. Thanks in advance for any advice you might have! -Steve Edited July 17, 2013 by WheelHorseSteve Share this post Link to post Share on other sites
Jeff-C175 7,195 #2 Posted July 17, 2013 I might start with a quick compression check. Backfiring can be caused by leaking exhaust valve. There could always be more than one problem... Share this post Link to post Share on other sites
pacer 3,159 #3 Posted July 17, 2013 Very likely ignition - I find that when I go thru a period of not working my D180 (just puttering around hauling, etc) that the p[lugs tend to carbon up and I get all this crazy backfiring, and will even sometime have one cyl not fire at all. I have found that by removing the plug wire on the cyl thats doing it and holding it (while running) some 1/2 to 3/4" away from the plug tip and letting the spark jump to the tip, that the backfiring or missing will almost always quit or at least change. I then know that the plugs have carboned up and need to be cleaned, or sometimes need to be replaced. Might give that a try, its sure a quick and simple way to check plugs. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,488 #4 Posted July 17, 2013 A bad condenser in a battery ignition system will do just that and drive you nuts. Make sure the condenser mounting bracket is grounded. Garry Share this post Link to post Share on other sites
SousaKerry 500 #5 Posted July 17, 2013 Also check that the float in the carb is not sticking open Share this post Link to post Share on other sites
WheelHorseSteve 48 #6 Posted July 17, 2013 (edited) Good leads everyone -- we're going to give these things a try. Some more info here: It has gotten progressively worse over the last few seasons. On start up there is a puff of blue/white smoke -- my bet is oil that has seeped into the combustion chamber (worn rings, cylinder, valves, etc.). Apparently it's a Kohler SINGLE -- I stand corrected (edited original post to reflect that). Anything else that we should be looking at? This circa-2000 engine... it must not have points and yes, it is electric start (w/ battery). Edited July 17, 2013 by WheelHorseSteve Share this post Link to post Share on other sites
wheelhorse66 10 #7 Posted July 18, 2013 have you ever had the head of it off, if you have you need to make shore the valves are flush evenly with the top of the motor, and the piston is flush with the top of the bore when the head goes back on or like you said it could be your rings ,and check your oil make shore it dosent have anything mixed in it Share this post Link to post Share on other sites
