[Shaggy]

My Case 444 (Kohler K321) seems to have a case of vapor lock. It will start fine, run great for an hr or 2 but then starves for gas, putts out and after 30-45 minutes it starts and runs fine. I tried adding insulation over fuel line that runs close to exhaust. Bad design Case. Reason I say it's that is I hear what sounds like water boiling, though TBH it's hard to hear much over the metal creaking, popping from it being hot too. Is this just an issue when in 100 deg weather? All shrouds are cleaned out as a mouse had a nest in there a few years ago but I cleaned that out. Fan works no blades missing. I can only think that it may be running lean and causing it to overheat. Help plz.

 

[a66coup289]

I had a similar problem on hot days with my 224, so K321 as well. I replaced the fuel pump which seemed to help some. My engine recently snapped a rod and during the rebuild I discovered a deep groove in the camshaft where the fuel pump rides, that basically rounded off much of the eccentric that activates the pump lever. The rebuild includes a cam with a good fuel pump eccentric surface so now I should get full pumping action. I hope that fully cures my problem. You might pull your fuel pump and inspect that for pumping ability and then take a flashlight and inspect the cam where the pump arm rides. You will need to turn the engine over a couple of times to inspect all around that surface. 10 minutes will confirm or rule out a potential problem. I checked my fuel tank, line and filter too to make sure all are free flowing.

 

[Harry]

If the cam running the fuel pump is a problem you could try a pulse pump or an electric pump.

Keep the Peace
Harry

 

[propane1]

All good suggestions above. I would also check your timing. If the engine is late in timing, it will run hotter than normal.

Noel

 

[Lionel]

How quick can you pull off the fuel bowl after shut down? No fuel in bowl, could be a vapor lock thing, fuel in bowl, something else is the problem. I'd also check the routing of my fuel line, and assume you are using new lines that aren't collapsing with heat designed for fuel?

 

[Bob MacGregor]

I have had several 444s here for repairs over the years and found several problems that contributed to interrupted fuel flow. One was a 1984 black frame model that had a lot of problems. The engine on this tractor had come loose from the the supports, rounded the bolt holes in the supports and pulled out two of the bolts from the bottom of the oil base. The engine support mounts had sagged to the point that the supports were chaffing on the tractor frame. Now what does this have to do with fuel flow? Actually a lot, as the vibration thru out the entire tractor during operation shakes up the gasoline to the point where it accumulates air bubbles similar to vapor lock. Kohler K series engines tend to vibrate more than twin cylinder engines and when the mounting system fails, strange problems show up. The air filter had shook from vibration to the extent that I had to fabricate a piece where the screws hold it to the carb and had to install thread inserts in the carb for the air filter mounting screws. I replaced the fuel line and ran it in the R/H side frame bay away from the hydraulic system heat source, slipped on a heat shield where it was close to the engine. With all this work and addressing a lot of other areas where vibration damage had happened, I started the engine and it ran for a while and it quit. The original fuel pump had failed and was replaced with new which forced the re run of the fuel line near the engine. I cleaned the cooling fins on the engine and checked spark timing which was off some. This tractor had also had a hole in the bottom of the transaxle housing caused by broken differential bolts. I was able to fill the hole with JB Weld and with new differential bolts, reassembled and reinstalled the transaxle.

 

[Shaggy]

All good ideas,
I've got a question though...
How do you check and/or change the timing? That is my first thing to check and fix. After checking/fixing timing I think I'll put on a cheap fuel pump as that will allow me to reroute fuel line away from muffler/exhaust. I also see many posts on problems with OEM and China knockoffs. So I think I'd be better off with a small electric pump, for multiple reasons. Thank y'all.

 

[propane1]

Find an engine manual for your engine. It should tell you how to set timing.

Noel

 

[danharry]

Check the compression when it quits. If it is low or zero, pop the head off and see which valve is stuck. Kohler engines were notorious for the exhaust valve sticking open when hot. The cure is to sand down the valve stem with emery paper or ream the valve guide. I've had to do this with every Kohler engine I ever had.

 

[johnkirkd]

Check for Spark when it shuts down. Check your point gap. Blow out cooling fins on motor and oil cooler.
On an Onan my point gap somehow got to about 0.030 not 0.020 per manual, pretty sure I set it at 0.20. Same, died after several hours and starts after cool down. I didn't notice the heat but, noticeably cooler after setting points, wide gap advances the timing making heat.

 

[a66coup289]

All good ideas,
I've got a question though...
How do you check and/or change the timing? That is my first thing to check and fix. After checking/fixing timing I think I'll put on a cheap fuel pump as that will allow me to reroute fuel line away from muffler/exhaust. I also see many posts on problems with OEM and China knockoffs. So I think I'd be better off with a small electric pump, for multiple reasons. Thank y'all.

Timing is checked through a little hole in the engine tin on the right side. (carburetor side) A timing light is needed. It is adjusted by setting the gap in the points.

 

[Harry]

On my 444 Kohler 321 with starter generator the timing hole is on the generator side, left side when sitting on the tractor. It's hard to find located under the generator. Does anyone know why some Kohlers have the timing hole on the right and some on the left?

Keep the Peace
Harry

 

[Bob MacGregor]

Hi Harry and group,
Here is the Kohler K series engines service manual and the parts manual for the k32, lots of different blower housings shown in the parts manual.

 

[Bob MacGregor]

Pages 72, 8.2 and 73, 8.3 of the service manual TP-2379 are where timing is discussed. Parts manual is for the K321 14 HP engine.

 

[Harry]

WOW! That's a lot of different blower housings Bob. Thanks.
Keep the Peace
Harry