bibby19 0 #1 Posted November 29, 2014 Hello, I have a 418-8 model WH with a Kohler engine. Rebuilt the motor last year and it ran great until the cold hit. Now it starts hard, and must run on half choke if you are below 3/4 throttle, or it will stall. The RPMs fluctuate up and down constantly. Have tried fresh gas and a little stabile with no changes. Any ideas?? Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,513 #2 Posted November 29, 2014 Welcome to the forum. Sounds like it is starving for fuel at a moderate throttle plate opening. Since it runs try a healthy dose of Seafoam fuel treatment in the gas and see if it clears a restriction in the carb. Have had good luck doing this with a reasonable amount of run time. Garry 1 Share this post Link to post Share on other sites
craigbic 47 #3 Posted November 29, 2014 Welcome to the forum! Agree with Garry, it definitely sounds like an air/fuel problem and that the carb is either out of adjustment or gunked a bit. Can try the gas additive to see if it works. I'm not super familiar with the 418-8, did that engine have an adjustable or fixed main jet carb? If it's adjustable then you could try following the adjustment procedure in the engine manual if you have a tach. Share this post Link to post Share on other sites
520HC 207 #4 Posted November 29, 2014 Make sure you move the air cleaner intake to cold weather position. These engines tend to run rough till warmed up. Share this post Link to post Share on other sites
bibby19 0 #5 Posted November 29, 2014 Thank you all. Sounds like the consensus is that the problem is either junk in the fuel system, or carburetor needs adjustment. I will try the seafoam and see if that helps. (520HC thank you I did move the air cleaner over to cold weather position earlier in the season). Share this post Link to post Share on other sites