IH model 70 engine question

[Horseshoe1970]

I have recently restored a model 70. The engine rebuild included new bearings, piston, rings, connecting rod, valves, carb, coil, and all gaskets and wiring. It starts and runs beautifully for about 10 minutes. After that, it acts like it is under extreme load, Boggs down and eventually dies. If I let it sit 20 or 30 minutes after one of these episodes it starts right back up. 100% original tractor, it does have the creeper option. When running tractor moves and acts as it should. Does anyone have any ideas? Any and all help appreciated.

 

[buck]

when its running, loosen gas cap, sounds like u might have a non vented gas cap,, as fuel is used from tank it puts vacuum on tank preventing further supply, common problem as the caps, vented and non vented look and screw identically, buck

 

[kmcconaughey]

Try buck's suggestion first, as I agree that can cause the same or similar symptoms, but this sounds like a bad condenser to me. If you replaced it when you rebuilt it, put the old one back in (providing you still have it). If you didn't replace, it try a new one or one from a different engine if you have more than the one Cub Cadet on hand.

 

[kaweimann]

Usually Bad Caps run crappy from the get go. (don't ask how I know this) My money is on the coil. I actually bought a cheap cap tester and the engine that was giving me fits had a dead cap! Coils that are suspect go bad when they get hot is my experience.

 

[abthomas]

Can you turn engine over by hand after it shuts down? Just wondering on a fresh rebuilt if something is getting tight after warming up ?

 

[buck]

i like the gas cap for this crime but do this, put tablespoon of gas in upside down cap, if it runs thru the cap, put it back on and look at next most likely culprit, i forgot about the condenser/capaciter capacitor?? dang they both look funny now, stroke crap, sorry, really gripes my butt, i was good, knew it, people i worked for knew it, now im not so good, forget stuff, anyway, work smart first, not hard first. look at most likely, least expensive, easu/quick, most notorious trouble spot, dang condensor, hope for te best, expect the worst, remember the last one you have of anything will dive onto the floor and run into the darkest corner or into thehardest hole to dig it out of, when u do get it out, it will have rolled thru the nastiest grease on the face of the earth

 

[buck]

i like the gas cap for this crime but do this, put tablespoon of gas in upside down cap, if it runs thru the cap, put it back on and look at next most likely culprit, i forgot about the condenser/capaciter capacitor?? dang they both look funny now, stroke crap, sorry, really gripes my butt, i was good, knew it, people i worked for knew it, now im not so good, forget stuff, anyway, work smart first, not hard first. look at most likely, least expensive, easu/quick, most notorious trouble spot, dang condensor, hope for te best, expect the worst, remember the last one you have of anything will dive onto the floor and run into the darkest corner or into thehardest hole to dig it out of, when u do get it out, it will have rolled thru the nastiest grease on the face of the earth

when she calls you in for supper, take off your greasy shoes, dont track greasy sand into her kitchen, they dont like that, change yr pants and shirt, wash yer greasy hands an smile, teller yer hqvin so much fun, and dont gripe bout her cookin, an be sure to hug andf kisser, tell her u love her, she could be taken out of your reach in a second and i guarantee there will always bbe something you will always be something you wish you had said

 

[dramsey]

I have recently restored a model 70. The engine rebuild included new bearings, piston, rings, connecting rod, valves, carb, coil, and all gaskets and wiring. It starts and runs beautifully for about 10 minutes. After that, it acts like it is under extreme load, Boggs down and eventually dies. If I let it sit 20 or 30 minutes after one of these episodes it starts right back up. 100% original tractor, it does have the creeper option. When running tractor moves and acts as it should. Does anyone have any ideas? Any and all help appreciated.

I don't know if you figured this out but I have had exactly the same symptoms you described and it turn out to be the fuel pet cock was vibrating most of the way closed after a few minutes of running and starving it for fuel, unfortunately the engine ran so lean it seized.

 

[kmcconaughey]

I don't know if you figured this out but I have had exactly the same symptoms you described and it turn out to be the fuel pet cock was vibrating most of the way closed after a few minutes of running and starving it for fuel, unfortunately the engine ran so lean it seized.

Wow, that's a new one that I had not heard before. Good thing to look out for.

 

[kashaver]

Did you do anything to the screen in the filter bowl under the tank during the overhaul? A partially restricted flow from the tank can cause that too.

I guess you need to determine if its losing spark or fuel when it dies. Does feathering the choke in easing it closed help?

 

[Horseshoe1970]

Forgot to mention it also has a brand new fuel sediment bowl. I checked the fuel tank cap and it did appear to be venting but I am putting a new one on just to be safe. I have not gone to buy that yet. I also plan on installing a new condenser even though the one that is on there is new. Very cold here in Indiana so I probably won't try anything until this weekend when I fire the furnace up in the barn. I want to thank everyone for what appears to be some pretty good ideas. I will keep everyone posted

 

[kmcconaughey]

Forgot to mention it also has a brand new fuel sediment bowl. I checked the fuel tank cap and it did appear to be venting but I am putting a new one on just to be safe. I have not gone to buy that yet. I also plan on installing a new condenser even though the one that is on there is new. Very cold here in Indiana so I probably won't try anything until this weekend when I fire the furnace up in the barn. I want to thank everyone for what appears to be some pretty good ideas. I will keep everyone posted

I take it that you didn’t hold onto the old condenser or coil. If you did, swap them back in one at a time.

 

[jfischer]

I had that same problem when I replaced the coil with a new one that was for a car. After replacing it with the one that is designed for that engine it ran fine.

 

[digger]

I had that same problem when I replaced the coil with a new one that was for a car. After replacing it with the one that is designed for that engine it ran fine.

Actually any 12 volt coil that has an internal resister will work just fine on our old Cubs.