Governor Problem

Tue Oct 19, 2004 5:53 am

First, thanks to all who have helped me get my '57 Cub into the best running condition it's seen in years. If you've been following my progress you'll recall that when I brought her home the governor was froze up, carburetor was gummed up, plugs points etc., hadn't been changed in years... you get the picture. I finished rebuilding the carburetor, straighting the casting, cleaning all passages, and adjusting the float as suggested by the websites several of you suggested - and that greatly improved performance, especially under load.

However, I still have slow and/or erratic speed control leaver response. First I suspected the governor, but further inspection reveals excessive play in the governor-carb throttle linkage. Except for a tiny bit of play at the key everything is tight at the rockshaft extension & the governor spring appears to be in good condition. The problem, I think, is wear at the spring attachment points, specifically the spring holes in the rockshaft spring leaver and the governor spring throttle leaver. The spring has worn the holes to at least twice their original size. As a result, you can move the throttle from full closed to nearly full open before the spring engages the leavers. I have two options:

1 - buy new leavers - about $110 for each.

2 - attempt a repair.

Repair seems my best initial option - I can buy the leavers after I screw-up the repair! So... do you think it possible to weld the holes shut and re-drill? Or... I'm wondering if I might be able to:

1) drill the hole out to say 1/4 inch,
2) tap the hole for a fine thread grade 5 or higher bolt,
3) loc-tight the bolt in place,
4) cut it off flush, and redrill the holes.

Any other ideas or things I've overlooked?

Tue Oct 19, 2004 7:20 am

IMHO, I wouldn't go any higher than grade 5 on the bolt... You do have to drill it, and for that operation, the softer the better.

Tue Oct 19, 2004 7:47 am

You might try filling it with JB weld and then drilling.

Tue Oct 19, 2004 8:03 am

And the keyway is easily fixed by making a shim or using Loctite, or as in the case of my old 48, doing both.

Tue Oct 19, 2004 9:35 am

You could stake the bolt in place too. Not to vigorous punch marks to bugger up the threads yet not crack the casting.

Tue Oct 19, 2004 10:25 am

I like the idea of using J B Weld, but I'm worried that it may not hold up well in the long term. I suppose I could have it professionally drilled and a bushing inserted; however,for the expense, I may be as well off to buy the new parts.

OK, so far at least no one has any vehement objections to the bolt idea. I guess the next step is to see if the casting is thick enough to be tapped effectively. I think 1/4 inch would be the minimum. I'll check on that tonight.

Tue Oct 19, 2004 10:53 am

Since the castings are thin, you might consider a fine-thread bolt.
Good Luck

Tue Oct 19, 2004 11:09 am

Just got a thought. You could drill and press in a roll pin with the slot away from the spring. You then would grind off what sticks out. The tension of the roll pin should keep it in place and keep it from turning. What you are dealing with here does not have to hold up a 1938 Fairbanks Morse or the queen Mary.

Tue Oct 19, 2004 3:58 pm

Another thought came to me while on the way to sears to pick Roundouts. Ease the edges of the holes if you use a bolt or roll pin. No sense putting sharp corners against the spring ends.
Also if I used a bolt I would mark where the centers were origionally and drill there not necessarily the center of the bolt. Of course if you clamp everything up in a drill press vise you could keep the origional centers. All this may be unnecessary if you have enough adjustment to make up for the centers being off.
Sorry to be so long winded. My wife tells me that I make a chemical annalysis fo every thing.

Tue Oct 19, 2004 4:31 pm

Here's another approach. Unless the hole is so badly worn that it is in danger of breaking out, work on the spring. The eyes on the spring can be closed just enough to eliminate the excess motion. It requires a delicate balance between eliminating all the play without putting any tension on the spring. Even if you repair the hole, you will still want to make this adjustment.

Wed Oct 20, 2004 4:21 am

Thanks Guys,

Using a roll pin seems to me to be a great idea. Thanks Bill. And I'll certainly make the spring adjustment George suggests.

I'll have to pull the governor off to make the repair... and as long as I'm into it I may as well refurbish any worn parts. I considered ordering all new bushings etc., but after reading the BR Servive Manual, I think I'll see what I find when I get into it. Any tips on what to look at while I'm there are appreciated.

On an unrelated note - I followed your directions on making the steel gas line - no leaks!

Wed Oct 20, 2004 2:50 pm

The older I get the slower I think and remember. I had a similar problem on my 68 Low Boy. The casting that goes from the hand throttle lever and turns on a pin on the governor cover had rust on the pin. I had tried penetrating oil and working it back and forth for a couple of years but it finally froze up solid. I wonder if you don't have a similar problem. Initially i would move the hand throttle and all that really happened is that the rod bent slightly. After being under strain for a while and with the vibration of the running engine the (what ever it's name is) would turn and the gov would increase speed. Mine froze solid eventually and I broke it trying to get it to move. I had to remove the cowl and tank, the generator, and the fan to get the governor cover off. I still could not free the movement up nor could I remove the part. Eventually I ground it so thin that it cracked along the pin. Came off real easy then. Putting the Gov cover back on involved removing the Dist and seal so that I could line up the punch marks on the gears. ( a miror would have saved the seal) After that it was put everything back following the instructions for cold timing the Dist.
As long as it was apart I decided to change the plugs. Disaster. Needed 3 foot of pipe on the end of a 24 inch breaker bar. The PO had installed tapered plugs and kept tightining till the leak around each plug stopped. I had to use a home made tap (made from an old plug) to clear the carbon from the threads. Put the new plugs in and when I started the engine it was a whole new world. With previous miss time and compression leaks I went from a hunk of junk to a powerful usable tractor. In my mind I directed a couple of ***###@@@** at the PO