CH740 in new CC XT3 surging & dies (FIXED!)

[stembridge]

New member, this is my first post here.



I bought a Cub Cadet XT3 GSX with a 60" fabricated deck last autumn, which I like a lot, except for the fact the Kohler CH740 rarely runs smoothly through a whole mowing. It's done this since new - I'd take it back to the dealer, but they're five hours away (I bought one of the last XT3s I could find anywhere, as they're discontinued now, and had to drive that far to retrieve it). We have a True Value store about a half-hour away that carries Cub Cadet, and I'll take it there if I can't troubleshoot on my own (with hopefully some help here!).

The engine will run smoothly for a while (maybe 30 minutes, although sometimes the symptoms start immediately, even from cold), but then it acts like either A) it's starved momentarily for fuel, or B) the ignition got switched off momentarily. Once this begins happening, it will progressively get worse until the engine dies.

I'm led to believe it's an electrical problem because it won't start about half the time once it dies completely (by that, I mean turning the key to the start position results in dead silence - no click, etc.). Letting it sit until cool usually means I can start it, but not always - I sometimes have to keep worrying it until it will eventually start. After I get it starting, it will continue to start okay again until it dies out as before.

The first time it happened was while mulching leaves in the autumn right after I bought it, which caked up the air filters pretty bad. Cleaning the filters seemed to help at the time, but with the new mowing season ramping up, it's got a fresh, clean filter in place (as well as fresh oil/filter since I'm past the break-in period). I briefly removed the air filter to see if that made any difference, which it didn't. Also briefly unscrewed the fuel fill cap, in case it had a plugged vent, but again with no difference.

My engine model is CH740-3328 and the s/n is 5127807843. It has about 18 hours on it.

I have the PDF service manual as well, and read all the threads here with CH740 mentioned in them. The ignition kill circuit seems like something that may be suspect, or possibly the key switch. But on a brand-new machine?

Any suggestions welcome!

Ed

 

[ILENGINE]

With it being that knew i would suggest take it back to the dealer and let them figure it out under warranty. There may be a history of CC having issues on that mower with that engine that may not be engine related.

 

[bertsmobile1]

Check the battery leads, both of them at both ends

 

[stembridge]

All connections I have access to seem to be tight. It cranked up this morning, but started acting up within a few minutes, then died with the no start condition again. I stopped at the True Value in town and they said they can take a look, but they’re backed up at least a week - the main reason I dislike taking anything in for service. I mowed last night (it died just as I finished and it sat in the yard overnight), so now’s the best time, I guess!

es

 

[stembridge]

It’s at the dealer now, will report back what they find.

es

 

[stembridge]

Back from the dealer, $70 lighter with no resolution.

As noted earlier, it had died after my last mowing, and while it cranked the next morning, it immediately started cutting out and then died again (no click or any noise when attempting to start). Wife and I tried to push it up the ramps on the trailer after me trying to start it multiple times; we couldn't get it all the way up the ramps, and wife said "try it one more time," after which it cranked up and ran fine. Perhaps we jiggled something in the process of pushing it up the ramps?? Who knows…

At any rate, the mechanic ran it 1.5 hours and it never hiccuped. Of course, I'm sure that means he cranked it up and let it sit, rather than actually driving it around with the mower running, simulating conditions under which it failed in the past. He apparently replaced two 20¢ connectors and said he went through all the grounds to make sure they were clean and tight. But since it did not exhibit any problems in their shop, it didn't fall under a warranty repair. The mech also wanted to argue that I should only use non-ethanol fuel (I've used stabilized pump gas for 30 years in all my small engines with no issues), and the owner then tried to blame the problem on my electric sleeve hitch, despite the problem having existed from new, before I added any accessories; not to mention the sleeve hitch uses the same type electric lift as that used on the factory deck.

Some of you older folks may remember the Model Garage series that ran in Popular Science Monthly from the late 1920s through 1970. One of Gus Wilson's repeated mantras was to find out what the actual problem was - especially if it appeared to be fixed for no apparent reason. That's where I feel I am with this shop.

I'll be mowing after lunch and we'll see what happens then.

es

 

[stembridge]

I'll be mowing after lunch and we'll see what happens then.

es

Ran perfectly the whole time I mowed, so there's hope!

es

 

[bertsmobile1]

IT can be very frustrating
I have run mowers for hours on end on the farm where my workshop is so the mower was working hard in mixed pasture grass and they never miss a beat , then when I go to unload them at the customers residence they play up , or they work perfectly for a coule of mows then the problem returns .

 

[stembridge]

Ran it another hour or so yesterday, moving mulch with the Johnny Bucket. It hiccuped once, while I had it idled down, but ran strong the whole rest of the time.

es

 

[stembridge]

Mowed today with no problems, then put another hour or so on the tractor moving manure with the bucket to fertilize some bare spots in the yard - again, no problems. Hope is growing that it might actually be fixed!



es