Cub PTO Stalling Engine?

equeen

Member
Perhaps the problem is with the PTO in some way???

50 Cub with 60" belly mower, runs fine for about 100 feet then engine wants to shut down. Depressing clutch for a bit prevents the stall/shutdown; but then runs 10 feet or so and wants to shut down again.

Electrical system is definitely good, fuel system is definitely good? How do I know? I have let engine idle for 15 mins or so with no problem. With PTO NOT engaged, I have driven around side yard for 3 or 4 rounds with no problem.

However, with pto engaged, I get about 100 feet. One day last week I did mow for about 10 minutes with no problem, but that was very unusual.

I'm running 80-90 gear oil in trans. I've lubricated the PTO shaft as well as 3 mower pulley shafts and have sharp blades on mower.

Ideas?

Thanks.
 
How far do you get with out he PTO in gear??? If you can drive it around with it out of gear but stalls when in gear I would try unhooking the belt for the mower and try it that way. May have a bad bearing on the mower deck.
 
I probably drove 500-750 feet with the pto disengaged and no problem.

Will try taking the belt off and running it with pto engaged and driving nothing.

Meanwhile....it has sprung a major leak at the line to hdy unit bracket. So, first item now is to replace that gasket.
 
You also might try this. With it not running and the PTO out of gear try to spin the PTO/mower by hand. If you find it is hard to do good chance you have a bear going on the mower deck. I have 2 finish mowers I need to replace bearing on SOON
 
i think it is starving for fuel also. do you have an aftermarket in line fuel filter? if so try taking it off. also check your oil bath air filter, that may need a good cleaning too.
 
Idling for 15 minutes takes a tiny tiny amount of fuel.

Full power for 10 seconds will drain the carburetor bowl.

If the fuel flow into the carburetor is restricted, it may be enough to support idling or even running full-out with no load, but with the higher demand for fuel under a load, it cannot keep up.
 
THANKS, Old!!!!

It spins freely, however one of the three drives is very noisy. I had thought that these mowers were just naturally noisy; but replacing that one with a spare I have will certainly reduce the noise.

Now, gotta find O rings for the hdy. I removed the hdy lines and replaced the gasket at the hdy unit end - and should have known to replace the O rings at the other end. But, I didn't and now it's leaking/squirting fluid at that end. Oh well, live and learn; but I'm sure looking forward to hearing those mower blades spin with a replacement drive!
 
Ya once a load is put on a rough or bad bearing they tend to bind and cause a problem like you are having.
As for the o-rings last I checked you can still get them for Case/IH
 
Does the mower drive belt get hot when the tractor stalls?
Check it as soon as the unit quits. If hot, feel the idlers
& bearings on the deck for a hot or dragging bearing.
Can you drive the tractor around for more than the 700 feet?
If you can provide a pulling load, instead of a PTO load,
try doing that & see how it proves out.
 
Well, Old...................

You've made me a happy camper. After changing out the most noisy of the three shafts/spindles/whatever, with another old - but relatively quiet - one, I mowed approx 1/2 acre in 2nd gear on relatively level ground. No stall or hesitation at all.

When I moved down to the fairly steep section of the side yard, I had to drop down to 1st gear and it almost stalled each time I came up the steep section - but never stalled.

Hopefully, tomorrow, I'll tear into the removed spindle and see if I can identify the bearings and get some before the next mowing. Will be interested in seeing how it works with new bearings on all three.

Oh, on the steep section of the side yard - after I finished mowing I dis-engaged the pto and drove the Cub up and down the hillside several times with no hesitation or attempts to stall.

Gene
 
Well a cub is only an over size lawn mower LOL. 12HP give ot take a bit so figure your mowing what 4 foot or so which is a pretty good load on it. Shoot now days they make 25HP riding lawn mower but bet they would not keep up to an old cub
 
Hey guys...doesn't the cub have separate lube for the PTO ? Check the owners book. You may be burning the crap out of your bearings in the PTO drive.
 
(quoted from post at 23:55:01 04/20/15) Yep, there's a grease fitting at the rear for the PTO shaft bearing.
Driving the tractor lubes the PTO. The grease fitting is for lubing the PTO when used to power a stationary item.
 

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