1976 1250 run problem

[dieselman81]

hi everyone!

Well, I'm obviously new here and having some trouble. since I'm a diesel tech I'm not savy on gas motors.

Here goes, the other day I was plowing my driveway with my 1250 and boom the engine went. Cracked the block. Found a used running engine in iowa 4 hours away, swapped engines. Now it wont run correctly. Went through the carb, all good there. Cleaned points and plug, has great spark. Adjusted carb to factory specs. Runs sometimes with choke in, sometimes with choke out. Won't accelerate then sometimes it will. Will start normal then die. Hard start run for a few seconds then die again. I've tried everything I can think of with no results. Any ideas? Please help! More snow on the way!

[Jeff in Pa]

Welcome

Have you tried putting the original carb on the new engine?

[Cub Cadet 123]

If someone has planed the head, then the carb settings will vary from factory specs--I had the same problem on my 149 recently and that would cause the rough running. Put a new spark plug in if possible and adjust the settings on the carb slightly. Also, on my 123, I have recently had problems of the throttle (and choke) cables freezing up on them. They free up once the engine has run for a moment or two or if I put some heat to them. I don't know if that is what is going on with yours, but I thought it might help to bring that up since we've had those Alberta clippers.

Cub Cadet 123

[dieselman81]

thanks for responding guys.

The carb on the tractor is the original one that was on the old motor and it ran great with that carb. tore it all down, cleaned it thoroughly twice, set to factory specs and ran and adjusted six ways from sunday with no results.

As far as the cables go, went through them both, cleaning and setting correctly. They are also good. Went as far as removing them to do all this to be sure the will work properly.

I was thinking, how do you adjust timing on a kohler k-301 or is it a fixed setting?

[Jeff in Pa]

Originally Posted by dieselman81

thanks for responding guys.

The carb on the tractor is the original one that was on the old motor and it ran great with that carb. tore it all down, cleaned it thoroughly twice, set to factory specs and ran and adjusted six ways from sunday with no results.

As far as the cables go, went through them both, cleaning and setting correctly. They are also good. Went as far as removing them to do all this to be sure the will work properly.

I was thinking, how do you adjust timing on a kohler k-301 or is it a fixed setting?

The cam is gear driven and is set (aligned) when assembled.

You can adjust the timing slightly with the points. When you did the points, did you use a feeler gauge or a timing light?

Here's a couple links Sam Mac posted in a different thread on setting points
http://www.onlycubcadets.net/forum/showthread.php?t=14

http://www.onlycubcadets.net/forum/s...ead.php?t=4405

[dieselman81]

As far as the points go, when I tried starting the new motor, it didn't have any spark at all. Checked and found the points a little corroded. Cleaned um up and now has good spark. How do you adjust the points and what is the setting.

Just wanna make sure the points we are talking about are the contacts on the lower left side of the engine behind a small cover right?

[Jeff in Pa]

Originally Posted by dieselman81

As far as the points go, when I tried starting the new motor, it didn't have any spark at all. Checked and found the points a little corroded. Cleaned um up and now has good spark. How do you adjust the points and what is the setting.

Just wanna make sure the points we are talking about are the contacts on the lower left side of the engine behind a small cover right?

click for bigger pic

The smaller cover on the left with the wire going to it

[dieselman81]

ok.

yes, we are on the same page. I have feeler gauges at work. have to try it out tomorrow.

If the gap is large would it spit and sputter and run and die the way it does or is that just a small running adjustment?

[Jeff in Pa]

Originally Posted by dieselman81

ok.

yes, we are on the same page. I have feeler gauges at work. have to try it out tomorrow.

If the gap is large would it spit and sputter and run and die the way it does or is that just a small running adjustment?

If the gap is incorrect ( either large or small ), it will effect the way it runs.

How it works
There is an eccentric on the camshaft which pushed a rod which in turn moves the points. The points are adjusted by loosening a screw ( snug it back up ) and very gently prying in the tab to either increase or decrease the opening. NOTE The adjustment is done after turning the engine over by hand until the points open the maximum amount.

I set mine with a timing light. On the opposite side of the engine is a small plug on the tinwork for the fan shroud. I shine the timing light in there with the engine running and adjust the point opening until the stamped letter on the flywheel shows in the center of the opening. I have model 125's , I'm not sure if yours has the same type opening.

[kostendorf]

I have a pdf. file on static timing to set your points using an ohm meter, but its to big to post here. I would have to email it to you.