Help; the case mechanic is stumped

[Eugene]

I've experienced the exhaust valve clearance problem and found it to work a little differently--- it shows up at high power and RPMs and goes away when the RPM is reduced, even slightly so the valve contracts slightly.

A bit of clarification. The valve tappet description provided in the explaination included all 4 exhaust valves where the clearance was incorrectly set. Normally, a wear caused problem with tappet clearance would only show up on one or perhaps two valves.

Keeping this short. I purchased a 610 Bobcat skidsteer cheap cause it ran like crap. Someone set the valve tappet clearance at .005 for an air cooled Wisconson engine.

No history on the grandpa's 47 Cub was provided.

Any way, it's an interesting problem. I'd really would like to know what caused the problem(s).

Eugene

[PageRob]

If you've got a dry tank, and its off the rig, is it easier to flush the tank, or try and suck it out with a shop vac or some such?

['Country' Elliott]

You stated that you "Changed the plugs and the coil". Did you put in a set of points and a NEW condensor ? Many times old condensors will opporate intermitantly, but not until the engine is warmed up, or under a load as you have described. Try replacing the condensor with a NEW one and see if the condition improves.

[drspiff]

If you've got a dry tank, and its off the rig, is it easier to flush the tank, or try and suck it out with a shop vac or some such?

Uh... My shop vac has a brushed motor and there are constant tiny sparks around the brushes. Sucking an air-fuel mixture through a shop vac is probably the first phase of building a gas turbine engine or flame thrower. I'd be real hesitant using any kind of electrical items around any air fuel mixture.

However, if you do this, be sure and take pictures.

Rick (An Avid Spectator) Dulas

[PageRob]

Uh... My shop vac has a brushed motor and there are constant tiny sparks around the brushes. Sucking an air-fuel mixture through a shop vac is probably the first phase of building a gas turbine engine or flame thrower. I'd be real hesitant using any kind of electrical items around any air fuel mixture.

Right. Good call. Need to put on my thinking cap sometimes...doh. I was thinking about my tank when I wrote that, which has been dry for some 20 years or so, not the average tank that's being used on a regular basis.

[carlevans]

At all of the casinos I been the house somehow gets a piece of the betting action. Since in this case I may be considered the “house” I should be entitled to a cut from the betting. However, after seeing what is being wagered I think I will decline.

As for the cub- If I were not at an age where keeping what white hair I have left were not so important to me I would already have the rest of it pulled out.

The governor, distributor and carburetor are disassembled and in pieces on the shop bench. The gas tank was drained, lines and sediment bowel were disassembled and cleaned and flushed again We found several small things like a weak return spring, small slop in the linkage; some wear on the points, old condenser and wire to the coil in poor condition. None of these were severe enough to cause the problem. Anything that looks a little off is being replaced as soon as we can get the parts. Perhaps all of the small things together contribute to the problem. In any event they would eventually have to be taken care of someday.

The valve tappet clearance will be checked. Hopefully, we may luck out and fix the problem with this “shotgun” approach whereby we fix everything and anything all at once.

I’ll keep you posted on our progress since there is so much at stake on the bet.

[Eugene]

At all of the casinos I been the house somehow gets a piece of the betting action. Since in this case I may be considered the “house” I should be entitled to a cut from the betting. However, after seeing what is being wagered I think I will decline. I’ll keep you posted on our progress since there is so much at stake on the bet.

Did I disclose in the fine print that shipping and handling charges are the responsibility of the wager winner.

Carl: Do you know the history of this motor? Has it been worked on/dissassembled prior to your obtaining the tractor? Frequently individuals will attempt to solve a small problem and end up making things worse.

Eugene

[carlevans]

I suppose I should have flipped to pages 2 and 3 and read them before I posted my last response. DUH!!!!! That is why I should not do mechanical work.

A couple of significant points. The tractor does not die. When it acts up it will continue running at a reduced speed with no power. I can shut it off and restart it immediately with no cool down period. It will come back up to full power immediately. Cool down period does not seem to be a factor. It does not miss or sputter –ever- it just looses power.

In fairness to the dealer - it is not acting up for them like it did for me. I could run 5 to 15 minutes before it would loose power. After about a 20-mile ride on a flat bed to the dealers the mechanic took it out to mow. After about 15 minutes mowing it died down for him and then came back before he could do much diagnostic work. He then mowed for about an hour in 6-8 inch wet grass in 2nd gear and it worked fine. Our best guess is that 20 plus miles of bouncing around on the truck jarred something loose or moved something back in place. But what? Will it do it again if I just bring it home? Probably.

A brief back ground on the tractor:
My grandfather purchased it new in 1947. After his death in 1957 my father inherited it. After dad died in 1973 I inherited it. It has always had the best possible care. It has always been sheded, had regular oil changes and service. Granddad had an acreage with fruit trees. He pulled a sprayer and used the mounted cycle mower in the orchard. I helped him with those things as his health declined. I used the mounted plow and cultivator to help with the large garden he and my dad would put out. After grandfather’s death my father only used the cub to plow snow and his small garden. I bought a woods 60 inch mounted rotary mower for the tractor after I inherited it and took to my farm. Interesting side note- I paid more for the woods mower than granddad paid for the cub with the cycle mower, plow and cultivator.

the tractor has never had a major overhaul or dissassemly. Grandad, my dad and I had any major work done at an I.H. dealers or other reeputable tractor repair shop. In the mid 1970's I had it converted to battery ignition at an I.H. dealers. It is still 6 volt

Even though I’m not mechanically inclined I’ve been around the tractor for so many years I’ve become accustomed to its actions and faults. This is like nothing I’ve ever seen it do before. I have the original manuals for the tractor and the equipment. Unfortunately they have been no help with the current problem.

Again- Thank you all for your help.

Cal Evans

[Bigdog]

It really sounds like dirt floating around in the gas tank. I would be looking for large chunks of floating debris in the tank which can obstruct the outlet. Especially if the screen is gone from the inside of the tank.

[Redman]

[Rob in NH]

muffler bearings, yup

[David C]

The suspense is killing me I cant wait til the end of the movie to find out the outcome... hahaha

David C

Just kidding I really hope you get'r'done

[carlevans]

Well, finally got the cub back. After one of the wheels on the woods mower falling off and running through the mower I finally got it fixed to where I could mow for a period of time to test it. It seems to run a lot better. Nobody is really sure what was wrong. The valve lifter clearance was within factory specs. The distributor was rebuilt. The carb was rebuilt. The governor was rebuilt. New plugs, points and condensor were put in. It will lug down under load but comes right back when the clutch is pushed in. It still does not seem to have the power it used to. I haven't got the bill from case yet. I'll be sitting down when I open it.


thanks for all the help.

[Eugene]

Sounds like it still isn't running right.

Try the vacuum test. You may be able to borrow or rent a combination fuel pressure and vacuum gauge from your local auto parts store.

Govenor opening up?

Eugene

[Buzzard Wing]

I don't know much.... but for some reason I suspected the condenser.... But I do believe that fuel flow, tank vent or valve clearance could cause it. Good explanation of the heat/valves. Just something about heat and electrical components sticks in my head.