127 quits running

CADET127 · #1 08-07-2015, 02:16 PM

Just wondering if anyone else has had this problem - it's a 1970 cub cadet 127 - 12hp koehler - hydrostatic drive - motor starts fine , runs fine , until after using it a while and good and hot , and it seems to be doing it more often lately , you will be going along and the motor will just , pow , and it will scare you , and the motor will just freewheel until it quits rotating , like something broke , valves stuck open . You can try it and it turns over with no compression . Sometimes you sit there for a couple minutes and it will start and other times it takes longer . I thought maybe at first it might be an ignition problem making it quit running . This engine has a compression release on the camshaft to hold , i think the exhaust valve open until it reaches a certan rpm . I don't know if maybe an ignition problem may be causing the quit running and maybe when it pops the compression release gets activated to cause the no compression or if the compression release is causing the problem . It will always restart after a little but man , when it pops or backfires it will just about make you want to jump off and run .

R Bedell · #2 08-07-2015, 02:28 PM

Quote:

i think the exhaust valve open until it reaches a certain rpm

Sounds like it is sticking open when it gets HOT.

Berwil · #3 08-07-2015, 03:12 PM

I agree with Roland, sounds like the exhaust valve sticking. Yes the compression release opens the exhaust valve to ease starting, but it's momentary and still keeps some compression. Sounds like yours is sticking open. I had the same issue on my 1450., I pulled the head and valves and cleaned everything up. Since then it hasn't shut off on me once.....except that one time I ran out of gas.

Bill

Terry C · #4 08-07-2015, 03:53 PM

I would go along with this assessment because if it was your compression release I doubt it would fix itself just cooling down.

CADET127 · #5 08-07-2015, 04:25 PM

I had thought the same thing once so i tried adding some marvel mystery oil and some lead substitute to the fuel being this motor was made when lead was being used and that was more or less a lubricant for valves and all. I even use the ethanol free gas . But it still happens . I plan on adjusting the valves and will see if i can tell anything from there . Thanks

olds45512 · #6 08-07-2015, 04:37 PM

The only way to solve the issue will be to remove the head and remove the valves and clean all the gunk off them, the job isn't to bad if you have some mechanical skill.

Yosemite Sam · #7 08-07-2015, 06:36 PM

I agree with the guys, there is no sense farting around with it.

Buy a head gasket, valve cover gaskets, carburetor gasket, pull the head, clean everything out, pull the valve out, clean the crud off of the stem, sand the head flat with 320 grit wet & dry paper and put it back together.

It's not rocket surgery but it does require some effort, it's a good way to spend a Saturday morning and part of the afternoon.

Cleaning it out and putting in a new head gasket is recommended maintenance (at what 500 hours?) anyway.

AND don't even think of putting that head back on without sanding it flat!

With these little Kohler engines, you reap what you sew.

At this point, adjusting the valves will yield you absolutely nothing.