782 getting hot
 

Hey guys, I have been busy using my 782 I picked up last fall.
Recently it started to surge after it gets hot.
I will mow for awhile and it it it start surging until it dies.
Then I can restart it and get another 10 mins out of it until it dies again.
I have found if I let it cool off it will run great.

A few days ago I decided to take the side panels off to see it that would help with the heat.
Sure enough I haven't had a problem since.
What gives?
What's the surging from? Vapor lock?
How do I get that to go away so I can put the side panels back on and mow on a hot day?

And because no thread is any good without pics..

The blower housing on the engine could possibly be filled with mouse nest.

Ok, I'll tear it down this weekend. And report back if I find anything.

Yep, give 'er a good blowdown. They need to have a lot of airflow to stay cool. Hopefully that's all it is. :beerchug:

My 782 acted very similar. Dying when it would get hot, then start back up when it cooled off. When I tried to start it when it was hot, it didn't have any spark.

I replaced the coil. I haven't had any issues since.

No mouse nests to be seen. It's been running better, but it's been cooler and I have been keeping the throttle down as well.

You want to mow at WOT (wide open throttle) as that not only gives you the best blade tip speed but also gives you better cooling for your engine. They were designed to operate at that RPM for mowing, take advantage of that :beerchug:

Well I get that, but it is run it at 3/4 throttle or mow and sit and wait....

Richen the top end.

Well.... how else would you know if you fixed it??

I agree with Terry. It's likely running lean.

I haven't done anything to fix it yet.
Just wanted to keep it going and get a few ideas of things to look for for when I dig in.

I have to mow tonight. I'll give it and see what happens. Now I have a few things to try to see what gives.

Meanwhile, running the risk of melting down a piston.... :bash2:


Yeah. You better see what's going on and fix it before you tear it up.

Tuning the carb to make it richer would only take a couple of minutes, you could make up that time by going wot instead of 3/4.

That's not a big deal to me. Would give me a chance to repower with something bigger and fuel injected.

:bigeyes:

Well, you were given some things to check and/or adjust. Looks like your mind is made up and you are going to let the engine die.

Seems looking for a re-power is in your near future.

Is it really that difficult to turn the main jet 1/2 turn CCW and see if that changes/corrects the problem?
Aw well, it is not for me to judge, good luck what ever you choose.

Wish I had 2 grand to spend on an engine. I'd build a new motor for my truck and have money left over!! :bigeyes::biggrin2:

next time when it heats up feel the coil is it almost too hot to touch? If so thats most likely the cause

I never said I wasn't going to adjust it. I'll dig into it before I go out next.
I'll blow it all out, power wash it again( to ensure it's clean in there), and adjust the carb some.
Not a big deal.

I was just making the statement that I wouldn't mind a few extra horses and fuel injection.
If the cub dies, it will give me a good reason to toss a paint job, new tires and some extra power at it.

Kohler command pro 23hp efi is only 2100 buxs....:bigthink:

Only? :BB&YS:

The tractor isn't worth half that....

:popcorn: :popcorn:

:Forgot: :Huh: :bigthink:

A small block chevy long block is is only 1600, through gm. Just sayin

It's his tractor and his money. If I had the money right now I would buy a brand new engine from small engine warehouse and restore this 784 to put it in, I could buy a new engine and completely redo the tractor and have less than 3k in it, once I was done I would basically have a brand new tractor. That would probably be the best 3k I ever spent.

I think that, if putting money into a 35 + year old tractor doesn't make sense because that it's not worth half that, then a garden tractor enthusiast webpage isn't the place to be.

Good point! What doesn't need a small block swap!?

Lol, although we might live in different worlds. The last small block chevy I built was somewhere north of 10. I didn't really keep track.

ooooooooh,
Zoomies on both sides of a red hood,
Heartbeat heaven!!!!!
:beerchug:

All fun aside guys, it's not that I don't want to fix the issue.
Obviously I posted here to see if you guys had experience with some known problems. If I wanted to swap engines just because of one issue, the command pro would already be ordered.

I'll just say that money isn't as a of a big issue for me as much as time is. I originally bought this for my father in law. He didn't like it. So I bought him a new John Deere instead. Trust me, a new engine and the cost of original purchase price is still less then a new Deere. Plus I honestly believe that it's probably built better as well.

I like it and don't really care about how much money I put into it.

ok
Do you have the adjustable main jet on top of the carb by the throttle shaft?
or it is the one on the side by the bowl lip?

The ones on the side by the bowl are lean from factory, and if slightly cruddy inside, they will hunt/surge and run chitty but just need cleaned and adjusted.
If the main jet adjuster in on top, just tweak it as they are fully adjustable.
( but can be cruddy inside also)
I just happen to like those old 2 cyl opposed twins, verses the new fool injected
"v" banks.
Nuttin wrong with new, I just like old skool and they work, and sound sweet to my ears.
Luck!

I'll have to look. I didn't get a chance to mow last night, nor did I mess with it.
It was sitting at my father in laws house this winter and it wasn't starting right. So I just had my father in law drop it off at the case IH dealer for a carb rebuild.
They rebuilt the carb, changed oil, new battery, air filter, and put a electric fuel shut off solenoid on it.
Then I picked it up for snowblower duty and we never got any more snow. Then it sat until June 1st, when I decided to pick it up and start using it.

So I highly doubt that the carb is dirty. (And I don't want to hear anything about the dealership.) Given the dealerships relationship with my family.
It might be possible that they set the adjustment screw to a factory setting causing it to run lean.

Ha-ha I remember then I was with my grandpa the first time when he heard a 25 horse v twin run, he said that old thing is on its last leg and going to blow up..... Haha it was brand new....

My hot-stalling 122 actually kept running when I firewalled the throttle. Good to know-- thank you.

I wish I could say that; I'm massively upside down on this 122, and I got it for free.

I didn't say it wasn't worth fixing,.... I'm just saying that I personally wouldn't put a $2100 motor in it. But, I digress. Money doesn't seem to be an area you lack in. If I had more of it, I'm sure i would spend it differently.

On this subject, what would you do if you had a 782 and the KT blew up?

I've got 2 7's, one with an S1 and one with an S2. I really enjoy running them, they are in good shape, and both are workers.

I'd want to do a Command swap with a new engine, but is it really feasible? I've not seen any used commands (or engine donors) locally.

Seems like the majority of 6-782s go to the graveyard when they die but I'd sure like to keep using mine for a while. Tough spot to be in.

I don't know Brian. I pick on people all the time on here for attempting to fix an H twin because, in my opinion, to fix it right is just too costly. By the time you're done you can almost buy a new CH. I'm in the same boat as I have a pretty nice 682 and a very nice 582 both with bad engines. I have a used CH I had planned on sticking in at least one of them.... but have yet to do it. I am with Ol George in that I really do like the old H motors. More torque than a V. I can't really give you any sway one way or the other than to say that it's awful easy to put a CH in a 782, and that used ones are pretty easy to find. (Or a Vanguard.) Me.... I could go either way. Fix the old, or install a used, or even new, CH. One way or the other it's just time and money. I do know one thing for sure..... none of mine are going to the boneyard over a bad engine! :biggrin2:

I am of the opinion that replacing the engine in a 782-2072 that has a blown engine is a way better move than spending money on a new plastic POS that is available today. I agree with Jon that they are probably not worth it as no body will give what they are worth when rebuilt but they are better than any thing you can buy today for the money you will have invested.

I just finished rebuilding a 1872 that includes a warranty take out 28 hp command EFI that I found for $1,100, I rebuilt the rear end and hydro, added a three spool hyd valve, front and rear hyd outlets, a three point hitch, New AG tires and a paint job. With the initial cost of the tractor I have around $3,500.00 invested in it and it is the nicest running and driving Cub Cadet I have ever drove. This tractor should last another 30 years if taken care of. What can you buy today for the same money that will last as long, and it is way better looking the stuff that you can buy today.

If it was me I would try to see why the 782 is overheating and correct it. Most likely adjusting the carb will cure it. I always run the hi speed fuel mix a little on the rich side to help with running hot. If and when you decide to upgrade to a CH engine having a good running opposed twin to sell would be a plus. Someone may have a use for it. Good luck
Tom

Mowed twice with no adjusting of the carb, at wot.
No issues.
I turned up the main 1/8th turn and the idle 1/16.
Mowed twice since turning them up. Still no issues. wot

Side panels still off.
Going to put them on and see what happens in few days when the low parts of my yard dry out and I can mow there.