Radiator 1948 Cub

[Plywud]

Well we went on our longest run so far, on the road for about 45 minutes. Got back and checking for oil leaks on things I think i have fixed and there is steam coming up from around the radiator cap. Little antifreeze leaking from somewhere on top under the hood, will check when it cools down a little. The current radiator is the one that came with it, not in the best of shape but no obvious damage that would make in inoraptable. The overflow drain tube is pinched off at the top and not connected to the overflow tube that goes down across the top and then down under the radiator itself. Tried to get it pressure tested, but because of the design, radiator shops I found can't work with this type anymore. This is my first time with a motor that doesn't use a water pump, is a little steam ok? Did not notice it while running around. Also seems a little weak on the power curve, had trouble getting it going in 3rd gear. Did a carb rebuild, starts right up every time, don't ever use the choke, but have not done a tune-up yet. Again is it normal to have it die when trying to start in 3 gear on a flat surface, now in all fairness thi was right after backing it out of the garage?

Thanks in advance for all the help

RJ

[Glen]

Hi,
The coolant leak could be that the hose clamps on the upper radiator hose need tightening.

You can look up under the hood from the left side, using a light, and see if the clamps are turned so you can use a short screwdriver, or wrench on them to tighten them.
You can reach up under the hood to tighten them.
The engine should be cold when doing that, don't burn yourself.

If you meant that the overflow tube is completely crimped closed, it shouldn't be run that way, if it has a good cap, and gasket, that seal well.
The pressure that builds up in the system has no way to get out of the radiator. You need to open the tube.
I saw one that was run that way in the past, it made the upper radiator tank expand, the metal bent, like inflating it with pressure.
Turn the cap to the loose position, so it is not tight, that will let the pressure escape, until you fix the tube.
The leak you said it had could have been the pressure trying to get out of the system, if the overflow is closed, and the cap seals good.

A Cub should start moving in 3rd gear, on a level surface.
If the engine was cold, then the choke needs setting to the right place, so the engine won't stall.
It sounds like the ignition timing could be wrong, the engine can have less power if the timing is wrong.
It may need a full tune up also.
The ignition points have to be good for it to have good power. They get old and burned from use.
You can do a compression test while all the spark plugs are out, then you will know if the compression is good. You need a compression test gauge for that.
Some auto parts stores rent them, they have said on here before.

[Plywud]

Did do a compression test when I first got it, 95 on the first cylinder, then 100 - 95 - 100. I think I saw 120 as normal. I have put off the tune up because it starts right up and idles just fine and other pressing problems to deal with to get it at least running; clutch, carb, brakes and a lot of grease and dirt. This is my first tractor and I'm not sure what 9 horsepower is suppose to look like.

Thank you

RJ

[outdoors4evr]

95 to 100 psi is still a workable engine. It may struggle a bit to run the power hungry implements like a 60" mower deck, but for most cub implements, this is fine. I'd keep working on the other issues first.

[Clemsonfor]

Untill you do a tune-up you can't really judge or even comment on power or running issues. You could be dealing with 30 year old parts. Pitted and strides cap and rotor. Your plugs were out so I'm sure you saw their condition. If acceptable it would work fine I'm sure. But yea the points and condensor need to be fresh as well.

And yes that tube like mentioned has to be open. The original can was not a pressure let off like modern ones it just sealed it. This is why it mentioned that you just turn it till loose so that heat and too much water if in there can push out.

[bofahs]

I'd be careful pressure testing that radiator - others more knowledgeable than I will have better info, but I think the radiator cap, for example, is 6 psi (?), whereas just about every other radiator in the world runs about 15 psi. Don't put a standard radiator cap on it. If you must, leave it loose. Then get the right one, right away.

In my experience, the coolant in the radiator will find itself a level about 1 inch below that neck, and then stay there forever. So, if you "can't keep it full", don't freak out - that's just what it does.

Do use something with a little anti-corrosive property to it - the first time I took mine apart, there was about 3 pounds of rust piled up in the bottom.

[Glen]

Hi,
Cubs came with a non pressure radiator cap standard, up to mid 1975, TM Tractor shows.
Below is a listing at TM Tractor showing the cap, you can look at the pics.

http://www.tmtractor.com/new/co/1642fp.htm

A pressure cap was extra if you wanted one. TM Tractor shows they are 7 lbs.
The radiator and cooling system need to be in good condition to use one, a radiator that is in poor condition probably won't work long with pressure in it.
There are 2 different lengths of filler necks, evidently, measure before buying.

http://www.tmtractor.com/new/co/2537fp.htm

http://www.tmtractor.com/new/co/3146fp.htm

The system shouldn't be filled to the top when the engine is cold, it is made to be filled to 2" or so below the filler neck when the engine is cold. The coolant expands as the engine warms up, and the coolant rises.
Below are pages from the 1965 Cub operator's manual telling about filling the system, to the left of the pic, and a little more on the 2nd page.

http://farmallcub.com/rudi_cub/www.clea ... age-21.jpg

http://farmallcub.com/rudi_cub/www.clea ... age-22.jpg