Z-134 Running Rough

My MF 135 Gas has been running well until recently and I cannot solve issue. It sputters through exaust with lack of power. It was last rebuilt 20 yrs ago and receives about an hour a week. The compression is 130-135-135-140. When I brought it into the shop to fix I replaced the distributor because it was an unidentifiable aftermarket and I wanted a Delco type to convert to EI sometime in the future. This made no difference in performance. The carb was removed, cleaned and a kit installed and this made no difference either. The timing is set at 6 deg. static. My assumption at this point is exaust valves but before I tear down I wanted to put it by the experts. I am getting a strong spark at plugs.
Thanks
Bob
 
thanks but the distributor is brand new, the plugs are clean and the carb is receiving fuel. It is experiencing the same symptoms as before the distributor swap and carb cleaning. This is why I am stumped.
 
There is lots I don't know, but don't understand how it could be valves if your holding compression.

Leaky float or intake restriction is what I would be thinking about... except that the plugs looking simular in color and clean and I would have expected soot.

One day it was fine and the next day this started showing up?
 
Did you first drain the carb bowl then turn on the gas checking flow or just loosen bowl plug only checking contents. There are at least 3 filters in the system, one in the tank, one in the glass bowl and one in the carb inlet.
I once had lose of power due to timing.
 
you are totally right about valves. If one was sticking whether intake or exaught then there would be loss of compression. I had a senior moment.
 
Other than it running rough, any change in the color of the exhaust?
Does partially closing the choke have any impact on how it runs?
 
There have been times with different carbs that I've had to take them apart more than once to get all the crud out of them. Last Z134 carb I rebuilt sat in carb cleaner for about a week until I got back to it. Never had issues with that one after rebuild!
 
I believe my MF 230 has the same engine. Double check the firing order and plug wiring. I believe distributor rotation is counter-clockwise 1 2 4 3. Mine acted similar to yours I thought rotation was clockwise and had it wired wrong
 
So you've gone through the ignition system, replaced the distributor, plugs are clean, good spark etc.
You have also removed the carburetor, cleaned it and installed a rebuild kit.
Are you able to identify possibly one cylinder that is causing you issues by removing one plug wire at a time and seeing if maybe one of them doesn't make a difference to the way it runs. On my TO35, when plug #4 would foul up it would run terribly. Pulling the plug wire would have no effect on the engine. Also, plugs that look fine and show good spark when testing, can fail when under compression.
Since cleaning the carburetor, have you removed it again to double check it?
I'm not doubting your work, it's just that I've been through similar troubles and 90% of the time, it's something I overlooked on the first inspection.
 
Similar to my experience with a 202 work bull. Ended up to be grease on newly installed points in addition to one plug not firing. After cleaning points and a new set of plugs she ran great. Seems the dizzy cam lube splattered on the points. If you have fuel, spark and timing it will run.




(quoted from post at 11:51:25 10/21/19) So you've gone through the ignition system, replaced the distributor, plugs are clean, good spark etc.
You have also removed the carburetor, cleaned it and installed a rebuild kit.
Are you able to identify possibly one cylinder that is causing you issues by removing one plug wire at a time and seeing if maybe one of them doesn't make a difference to the way it runs. On my TO35, when plug #4 would foul up it would run terribly. Pulling the plug wire would have no effect on the engine. Also, plugs that look fine and show good spark when testing, can fail when under compression.
Since cleaning the carburetor, have you removed it again to double check it?
I'm not doubting your work, it's just that I've been through similar troubles and 90% of the time, it's something I overlooked on the first inspection.[/qote]
 
Thanks everyone for their responses. I have gotten the tractor to run better but not great. I still get sputters at idle but it is running good under load.
Thanks again for all the kind responses.
Bob
 

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