My 644 gave up the ghost

[Eugen]

My 644 stopped working after about an hour and a half of gravel loader duty, a few days ago. Before stopping altogether it wanted more and more choke. Had no time to deal with it until today. Noticed it was also out of gas, so refueled it and tried to get it started again.

It would start only with the choke on, and does not stay running. The spark looks good, the pump seems to pump fuel, the carb bowl is full. So what now? I got a carb I knew works from the 244 and put it on the 644, same thing. Eventually I got it to run a little longer by plugging the two holes on the choke carburetor butterfly, but it runs at low rpm, and as soon as I open up the choke it dies. No matter what I tried, like adjusting the jets, nothing made it work better.

More troubleshooting needed.

[JSinMO]

My first thought was what David posted on the thread about mine not running right. Look for an air leak. Maybe in the intake seam or where the intake mates to the head.

[propane1]

ship the tractor to me Eugen. And I’ll fix it over a long time.


Noel

[DavidBarkey]

My 644 stopped working after about an hour and a half of gravel loader duty, a few days ago. Before stopping altogether it wanted more and more choke. Had no time to deal with it until today. Noticed it was also out of gas, so refueled it and tried to get it started again.

It would start only with the choke on, and does not stay running. The spark looks good, the pump seems to pump fuel, the carb bowl is full. So what now? I got a carb I knew works from the 244 and put it on the 644, same thing. Eventually I got it to run a little longer by plugging the two holes on the choke carburetor butterfly, but it runs at low rpm, and as soon as I open up the choke it dies. No matter what I tried, like adjusting the jets, nothing made it work better.

More troubleshooting needed.

@Eugen Start with a compression test . If you do not have a tester come borrow mine . Should have about 75lbs WOT. Check valve clearance , If ok disconnect muffler and try again ,
lean working hard make excessive heat . warped head, mufflers clolpsing internal , valve ware/ damage

[DavidBarkey]

@Eugen If the head gasket is gone I have the mill and plate for measuring and sanding flat . I might even have a gasket , have to check that . let me know .

[propane1]

Jumpins Dave. He might have shipped to me.


Noel

[Eugen]

Thanks for your good suggestions guys! I'll take it one step at a time and report what I find. I got Thursday and Friday off so there's a chance I get to it.

[Eugen]

ship the tractor to me Eugen. And I’ll fix it over a long time.


Noel

For a bowl of chowder!

[Eugen]

@Eugen Start with a compression test . If you do not have a tester come borrow mine . Should have about 75lbs WOT. Check valve clearance , If ok disconnect muffler and try again ,
lean working hard make excessive heat . warped head, mufflers clolpsing internal , valve ware/ damage

Thanks Dave, I got a tester but the Kohlers have the automatic compression release remember?

Yeah, I was thinking along the same lines, valves, head. Didn't think of muffler collapse, that's interesting.

@JSinMO the Kohlers don't have an intake manifold like the Onans, the carb is bolted directly on the body. But when I took off the old carb I noticed that the thick gasket was very hard and maybe a little waroed, might have allowed air in thus make it run lean and overheat. hopefully not too much damage ensued.

[DavidBarkey]

@Eugen Start with a compression test . If you do not have a tester come borrow mine . Should have about 75lbs WOT. Check valve clearance , If ok disconnect muffler and try again ,
lean working hard make excessive heat . warped head, mufflers clolpsing internal , valve ware/ damage

Thanks Dave, I got a tester but the Kohlers have the automatic compression release remember?

yes , thats why you only get about 75 psi

Yeah, I was thinking along the same lines, valves, head. Didn't think of muffler collapse, that's interesting.

If it has blown the head gasket it will be sucking air in there as well as loosing compression

@JSinMO the Kohlers don't have an intake manifold like the Onans, the carb is bolted directly on the body. But when I took off the old carb I noticed that the thick gasket was very hard and maybe a little waroed, might have allowed air in thus make it run lean and overheat. hopefully not too much damage ensued.

I should have a carb gasket too.

Note: I have a gasket , If need just come get the head flat grab the gasket and bring me a replacement gasket when get one . Get you back running fast .