Tue May 11, 2004 10:24 pm

My cub was overheating last year, and acting like it was going to stall. After cleaning the carb, and radiator fins it ran great.

Now today it started acting like it was going to stall again when cutting. I check the radiator level, its ok. The radiator fins where fine.

It seemed like the problem primarily was evident when the belly mower was engaged.

Any idea?

NOTE: I am not a great engine mechanic.


Wed May 12, 2004 12:17 am


While under a load such as having the mower running it puts on more of a load on the engine causing it to run harder and then in your case it overheats. Here's a couple of thoughts of mine, goes with most mechanical theory. I'm new to these Cubs myself, but really like what I am seeing, simple but yet so rugged.

You may want to check your timing, it might be retarded a few degrees. I don't know the proceeure yet, but I noticed that there is a timing pin on the front cover and a couple of marks on the front pulley. I need to re-install my dist this weeks almost done with the restore. I am sure that each one of these marks means something. I am waiting on my shop manual to arrive or I would give you these specs. May also want to check the gap in the points too.

ALSO, when I took off my radiator, there was about a gallon and a half of nasty gooey sludge in the bottom of the the cast iron bolster. It was almost to the top of the lower radiator inlet. While I had it off I ran some stiff wire through each of the radiator tubes and high pressure wash it all out. the flow was GREATLY increased.

It might be worth you time taking out the pipe plug in the bottom and seeing what comes out, if anything does and then you could run a garden hose in the top of the radiator and see how it flows. If it gunky and sluggy, you may want to think about taking off your radiator and check the tubes. It's not a real big deal to get it off, you may or may not twist off a few bolts. Especially if they haven't been off in years, like mine was. BUT if you take you time, they should come out and not break any off. I was lucky. I replaced mine with stainless steel bolts and used antisieze on the threads. If I remember right they were 5/16" NC by 7/8" long.

Good Luck,


Wed May 12, 2004 8:01 am

John N gave you some very good advice, but are you sure your cub is overheating now, are is it just trying to stall. If it's overheating it whould be boiling when you shut it down, or blowing a lot of water out the overflow. also remember these are thermosyphon colling sustems, and they will push excess coolant out the overflow until they get aobut 1 to 1 1/2 inch below the overflow. Also check the fins, the 49 I bought a couple of years ago looked clen, but it was plugged up deep inside the fins and couldn't be seen. If it's not overheating, you may need a tune up, and carberator clean/adjust.

Overheating - 4 Sure

Wed May 12, 2004 6:38 pm

It is overheating.

I checked a few things out today after getting home from work, cleaned the air breather, and checked the fins.

Then proceeded to cut the rest of the grass I did not get completed last night. It took about 15 minutes - tops. When done the radiator was very hot. More hot than in the past I would say.

I do not think it needs a tune up. It runs smooth - most of the time until now. I did change the plugs, plug wires and distributor cap last fall. The points looked ok.

It ran fine today, but was very hot in short time.

How can I be sure the fins are clean without taking the radiator apart?

What is the the pipe plug in the radiator. Can you give more detailed instructions for flushing? Do I need to take it apart to do this? Can I just remove the bottom hose?

I cleaned the carb last fall very well.

I have never worked on a tractor - before this one. So please be explicit if you have some ideas.

Wed May 12, 2004 6:53 pm

The drain plug (pipe plug) is in the very bottom of the front casting. If it hasn't been removed in a while, it can sometimes be a challenge. The lower radiator hose won't completely drain the radiator tank, in addition to being a pain to remove.

Wed May 12, 2004 7:03 pm

The plug is a square headed bolt on the bottom ,underside of the bolster.But sometime they get out of shape.Take it out but be carefull.Run a water through the top of the rad and flush it well.After yhe water comes clear.before you put the plug back in.Bend a piece of coat hanger and see if you can scrape any sludge out of the botom of the bolster.This will tell you if you have to take the rad off.Most likely you will.Good Luck 8)

Radiator snafu

Thu May 13, 2004 6:33 pm

Well I could not get the drain plug out easily since it was in tight, and the head looked like it was going to mash. Luckily I stopped before it had.

It looks as if it has never been out in the recent past. So I sprayed some WD40 around it a few times. After an hour or so it looked like it was somewhat cleaner. So I sprayed her again and am letting it sit.

Is there an easier way to help it get unstuck other than what I am doing?

If it does mash down, are these size drain plugs easy to find?


Thu May 13, 2004 7:37 pm

You might try using a piece of wood tapping it lightly with a small hammer.When I got mine out I replaced it with a brass plug I got from a plumming store it will not corrode as easy I also used plummers tape on the threads :lol: :

Thu May 13, 2004 7:37 pm

They are standard 3/8 pipe plugs.

Overheating adjustments

Sat May 15, 2004 8:04 pm

I made some adjustments today. I still can not gt the drain plug out. But after talking to a local farmer, he made a few suggestions. I adjusted the carb and air hose. He thought the hose was a bit bent in one spot and may been restricting the air flow. Very possible.

He then said that if the adjustments do not work, then it is not that the radiator was full of slug, but that the tubes that the water travels was plugged due to the years of use.

Therefore it may be due to change the radiator if the adjustments do not do the trick.

I am going to cut Monday or Tuesday and see if it gets hot.

Where can replacement radiators be purchased?


Sat May 15, 2004 8:13 pm

Rather than replacing it, take it to a radiator shop and have them boil it out. Much cheaper.

boil oit radiator

Sun May 16, 2004 7:04 am

Thanks for the tip. I appreciate it. Is there any other updates suggested to be made when and if the radiator needs to be pulled an boiled out?


Sun May 16, 2004 7:35 am

Jeff if you plan on removing the radiator you will need a to replace the gasket That may to be purchased from the local dealer . Just ask the local farmers where they get there parts .And you may want to start soaking the radiator bolts with some penitrating oil now that way thay may be removed when you need to remove them I use a product called Deep Creep I buy it at the local TSC . There are other products out there some use Kroil everone has a favorite . But I keep 2 cans on the shelf all the time . When you work on the old stuff it makes sense to just keep it around good luck Steve

Sun May 16, 2004 10:59 am

You may want to laugh when I tell you this.If you end up taking the rad off ,you will be cleaning the sludge out of the bolster.After it is cleaned take a small torch and heat slightly around the drain plug from the inside of the bolster.Take an old wax candle and melt the wax into the threads of the drain plug from the inside.This has worked for me with some rusted nuts and no hazardous fumes from burning solvents.Give it a try you have nothing to lose. :idea: :roll: :lol:

Re: boil oit radiator

Sun May 16, 2004 12:55 pm

winrelic wrote:Thanks for the tip. I appreciate it. Is there any other updates suggested to be made when and if the radiator needs to be pulled an boiled out?

It would be the ideal time to replace the fan and generator belts.