Cub lacking the power it should have

old · Jul 9, 2022

So I had planned to do a bit of mowing but the Cub had other ideas. For some reason yet unknown it is lacking the power it should have. I tried to engage the mower and drive it at the same time and almost killed the engine doing so. Engage the PTO and the mower will spin up but not at the RPMs it should and the engine labors just o stay running.

I plan to go out after it cools down and pull the spark plugs and see what they look like. I know I have good gas flow to the carb. Just doesn't make any sense because the last tiem I used it it ran just fine.

DoubleO7 · Jul 9, 2022

Air intake restricted?

old · Jul 9, 2022

With the air cleaner unhook it runs the same. Pull the plugs and they are all black and sooty. I cleaned them and it ran a bit better but not as it should. I may try hotter spark plugs. Has NGK AB6 plug in it now

Janicholson · Jul 9, 2022

If distributor, a stuck advance will do it! Jim

centash · Jul 9, 2022

Black and sooty plugs would make you think its running rich....could the choke linkage somehow jiggled into a partially closed position?

Ben

flying belgian · Jul 9, 2022

Did the distributor come loose and get out of time?

Absent Minded Farmer · Jul 9, 2022

Did you check to see if there was something going tight or binding on the mower?

Mike

old · Jul 9, 2022

Distributor was good and tight but I did take it loose and I adjusted the timing a bit and it is now running better at least till I ran out of gas that is. I figured after I added more gas it might start hard due ot the adjusting of the timing but it fired right up nice and easy

old · Jul 9, 2022

I adjusted the timing a bit for max RPM and it is now running better then it has since I have had it

old · Jul 9, 2022

Mower is as it should be and I can turn it by hand real easy

John T · Jul 9, 2022

Hey there Rich, you know this stuff ESPECIALLY YOUR TRACTOR better than us, I'm sure you will figure it out.

When you say the plugs are black n sooty, I agree with that posted below, sounds like she's running too rich (you know that already). Maybe a restriction in the air cleaner,,,,,,,or air inlet piping,,,,,,,,,or choke butterfly plate is not fully open,,,,,,,,or carbs power jet too rich,,,,,,,,, or float level too high,,,,,,,or timing way off ???

Maybe the spark is too weak n wimpy ?? Points or condensor or dist cap rotor or plug wires?? Try new plugs maybe??

It can help reduce black carbon plug fouling if the engine runs hotter or sure as you mentioned try a hotter plug.

Maybe the timing got slipped too slow ????

You will get it probably already have,,let us know what it was

John T

old · Jul 9, 2022

Not sure this is what was wrong but I adjusted the timing a bit to the point I got a few more RPM out of it and it then had power again. But what gets me is the distributor has not moved any from where it has been set since I got it up and running last summer

4wdtom · Jul 9, 2022

The idea below of stuck advance mechanism seem like it could be likely.

tomturkey · Jul 9, 2022

Old, you already know all the checks to be made to trouble shoot this problem. But maybe you've got some baler twine wrapped up around a spindle putting a drag on your engine. Was down your way last week, boy was it hot. Good luck with your mowing. gobble

old · Jul 9, 2022

Yes it has been hot here. But today I mowed with the Cub and with the BA and never broke a sweat.. I'll probably bale hay on Monday but I'm sure I'll break a sweat then

Cub lacking the power it should have

old

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