"Manic-Mechanic" 1,196 #1 Posted March 12, 2021 I have this great tractor but it’s been driving me nuts for years! I’ll warm it up, drive around it’s perfect, no sputters or misses. Then I’ll park it at idle and it’ll slowly begin to decelerate and stall if I don’t tap the throttle? Checked fuel line integrity. Compression. Fuel pump. Finally, carburetor. valve issue? IMG_5657.MOV Share this post Link to post Share on other sites
Stepney 2,335 #2 Posted March 12, 2021 My old Arctic Cat had a K301 and responded just the same way. Fine under load, and it would slowly peter out. Worn throttle shaft dancing around in the carb bore was my issue. Could also maybe be a weak fuel pump as far as a tractor may be concerned. 1 Share this post Link to post Share on other sites
JoeM 7,885 #3 Posted March 12, 2021 What is the idle RPM? sure seems low in vid. Might have to richen it up a bit at that level. After it idles a and shuts off what does the spark plug look like? 1 Share this post Link to post Share on other sites
Jeff-C175 7,203 #4 Posted March 12, 2021 9 hours ago, Stepney said: Worn throttle shaft dancing around in the carb bore Could be.... Spray some starting fluid at the ends of the butterfly shaft while it's running, see if it speeds up. Those can sometimes have bushings installed to restore the tolerance. 1 Share this post Link to post Share on other sites
"Manic-Mechanic" 1,196 #5 Posted March 12, 2021 18 minutes ago, JoeM said: What is the idle RPM? sure seems low in vid. Might have to richen it up a bit at that level. After it idles a and shuts off what does the spark plug look like? I had adjusted the idle screw many times back and forth, there is a happy medium but I prefer the least vibration at lowest idle. Share this post Link to post Share on other sites
"Manic-Mechanic" 1,196 #6 Posted March 12, 2021 5 minutes ago, Jeff-C175 said: Could be.... Spray some starting fluid at the ends of the butterfly shaft while it's running, see if it speeds up. Those can sometimes have bushings installed to restore the tolerance. I can give that a “shot!” Lol Share this post Link to post Share on other sites
"Manic-Mechanic" 1,196 #7 Posted March 12, 2021 9 hours ago, Stepney said: My old Arctic Cat had a K301 and responded just the same way. Fine under load, and it would slowly peter out. Worn throttle shaft dancing around in the carb bore was my issue. Could also maybe be a weak fuel pump as far as a tractor may be concerned. You may be on to something there, this is a very old carb, Jeff-C195 mentioned the spray. I know the linkage will lift right off the shaft, (will no longer tighten up) Share this post Link to post Share on other sites
8ntruck 7,254 #8 Posted March 12, 2021 (edited) My K321 was doing the same thing. The cure I found was to richen up the idle mix about 1/2 a turn. Sounds like you've already been down that road, though. Checking for a loose throttle shaft sounds like a good idea. If it is worn and leaking, the idle adjustment may not be able to compensate for the extra air. Edited March 12, 2021 by 8ntruck Share this post Link to post Share on other sites
pfrederi 18,159 #9 Posted March 12, 2021 Keep in mind Kohler idle speed is about 1250 2 1 Share this post Link to post Share on other sites
oldlineman 1,489 #10 Posted March 12, 2021 That's what I was thinking ,engine needs enough idle speed to splash oil for good lubrication and cooling. Bob 1 2 Share this post Link to post Share on other sites
