2135 issue. Overheating?

[rb608]

I have an chronologically older 2135 w/ a 13 hp Kohler, with <200 hours on it. I'm having a chronic problem, but I'm not savvy enough about small engines to have a clue.

It mostly runs great. It'll start up fine, run perfectly, and cut grass for about a half hour before the problem arises. It's as though the timing goes to heck of a sudden. It loses power, backfires, and dies. If you try to restart it, it just won't, but it'll "try". Maybe a few low rpm chugs, more backfiring, but no start. You just have to leave it where it is for a while then go back; then it'll start right up as though there were no problem at all.

Because of the time-related correction, I'm suspecting a temperature issue, but the characteristics have the characteristics of a timing problem. I've sort of discounted timing because that's not something that'll just suddenly go wrong, right?

FWIW, last season I replaced the muffler and the carb; but the problem predates those repairs.

Any help?

Okay, I'm going to go finish my lawn now. TIA.

 

[diesel_nut]

Is the engine screen covered with clippings? Gas cap vent clogged?

 

[rb608]

Engine screen is clear. The gas cap vent appears damaged. I'll have to check to see if it's open.

 

[OldMachinist]

Engine screen is clear. The gas cap vent appears damaged. I'll have to check to see if it's open.

If the vent is clogged loosening the cap should correct the problem fast but it sounds more like vapor lock or a clogged fuel fuel filter. Check to make sure some small critter hasn't built a nest somewhere blocking air flow causing the fuel line to get hot. I have a big problem with mud dabber wasps building nests in the cooling fins of engines all the time and mouse nests builted over the winter.

 

[rb608]

I've had other engines sabotaged by those little insects; methinks that's a very plausible idea. I hope so, because now that I've asked the question, the sumbitch won't start at all. Wants to, just won't. I'll run the fuel line & check the air supply. Tx.

 

[magicalj]

Another member on this forum had the similar issues with his 2185. His was a bad coil. You should check out his thread.

AJ

 

[rb608]

Well, I checked over everything external to the engine & found nothing out of the ordinary, except one thing. The green foam rubber cover around the air filter looks to be deteriorated. (It's new last year, so I suspect mice.) Is it possible I'm getting too much air through that, causing it to run to lean?

 

[rb608]

Another member on this forum had the similar issues with his 2185. His was a bad coil. You should check out his thread.

Thanks. I checked the jgrinn thread; but its different symptoms. Mine isn't bogging down, it's just chugging, backfiring, and quitting.

 

[savageactor7]

I'm with the poster that suspects the coil...also it happened to an older Cub we owned. Ran fine for 20 min then died when the coil got hot.

 

[diesel_nut]

Although backfiring is a sign of a lean condition I doubt running it even completely without the green pre-filter would cause a too-lean condition.

 

[dqdave1]

Pull the spark plug; what does it look like? White - lean; gray - normal; black - rich.
Does it have points and condensor? If it does; change points and condensor, while you are at it, change the plug. Coil is a possibility; they normally act up when they get hot.

 

[rb608]

Tonight, I made it 3 minutes before it quit. Last weekend, it ran for almost 15 minutes before giving up. If this were predictably reproducible, it would be easier.

To answer a few previous questions: It appears to be electronic ignition. No, I haven't pulled the spark plug.

I tell ya, when you first get on, it starts and runs perfectly. Then it quits when it feels like it. Because it behaves as though the timing just goes to heck all of a sudden, that at least supports the ignition module hypothesis.

The only other "new" symptom I'll offer is that #1 Son pulled the dipstick after one of these episodes, and it has a few small bubbles on it. Oil level is within the limits on the stick, but is at the high end. No clue if that's pertinent.

 

[rb608]

Since I got some good suggestions here, I thought I'd post the ultimate resolution of the saga:

I finally broke down & took it to a local shop. They let it run for an hour, but it never shut off. So the next day, they went for an hour and a half. Still fine. I suggested that it probably needed to be under a bigger load, and they should cut some grass until it quit.

That was a good idea, except that in running it so long on previous days, a hole in the muffler melted the deck belt. Okay, a few more days to get that fixed, then they were finally able to reproduce the problem.

When it quit, his first thought was ignition coil. (Everyone who suggested that was right.) But it was a bit worse than that; I had a mouse nest in behind the blower cover, and they'd chewed the insulation off of everything.

The shop pulled the engine & fixed it all. $427 (including the new belt & muffler repair.). Ouch; but I was able to cut the entire lawn at one time for the first time all year.

 

[OldMachinist]

Glad you got it all figured out.
Critters of all kinds can cause problems with air cooled engines. The best way I've found to cut down on the nests built while equipment is being stored is to cover the engine with a plastic trash bag and put a cloth bag of moth balls inside. Seems to work for rodents, spiders and wasps.

 

[diesel_nut]

I'd think when there is an over heating issue the shop would check for that FIRST!

 

[OldMachinist]

I agree, if you look at any air cooled engine troubleshooting chart for overheating the first thing on the list will be clogged cooling fins.

 

[Donsyl]

The closed in side panels dont help the overheating issue either. There is no open sides for the engine to breath. The older cubs in the 60's and 70's never really had those issues. I had a 2135 model and it overheated on me, but by then i was already so disappointed in it that i didnt care anymore. I never should have traded the 1964 model 100 that i had for it. I now have a 1988 model 1811 that i just love, but it has the closed in side panels, and the engine compartment gets hot pretty fast.

 

[rb608]

I'd think when there is an over heating issue the shop would check for that FIRST!

To be fair to them, I did not diagnose it to them as an overheating issue, I only tried to describe the symptoms. Once they were able to reproduce the problem, the fix was quick.