[motox25]

I've been having problems with the governor on my 520-H ever since the engine was rebuilt by another mechanic :fing20: so after looking at forums on here and getting a copy of the manual I've decided to tear into the engine myself. Problem I'm having is the engine races and the governor doesn't seem to function except by small "taps" on the arm at high speeds. I'll be documenting the entire repair and I'm sure asking questions along the way, so :thanku: in advance.

Hood removed

 

[motox25]

I noticed the wire clip that leads from the alternator to the voltage regulator is burnt, in the manual I saw meantion of a capacitor however mine doesn't have one attached, is it supposed to and could this be the cause?

 

[motox25]

Got the flywheel and gear cover off and I found the problem! :thThumbsU (at least one of them)

According to the Onan manual, The camshaft centerpin extends out 3/4 inch (19 mm) from the end of the camshaft. This distance provides an in-and-out travel distance of 7/32 inch(5.6 mm) for the governor cup, as illustrated. Hold the cup against the flyballs when measuring. The camshaft center pin cannot be pulled outward or removed withdoaumtage. If the center pin extends out too far, the cup will not hold the flyballs properly. If the distance is less than 7/32” (5.6 mm), the engine will race, especially at no load. Remove the centerpin and press in a new pin. I have hardly any travel distance for the governor cup, far from 5.6MM.

How does one go about removing the center pin? Just pull it out with vice grips? When "pressing in" a new one, should I tap it in using a rubber mallet? The way I interpret the manual I can remove and install a new centerpin without replacing the camshaft, is this correct?

 

[motox25]

The parts I ordered came in today. New camshaft center pin, gearcase gasket, and some bolts and washers that needed replacing. Now to just find time to put them on!

 

[99flhr]

If you are going to "tap in" a new pin, can`t you just "tap" the existing pin in deeper ?

 

[motox25]

If it weren't in far enough I could, however the pin was pressed in too far by the mechanic that rebuilt the engine.

 

[glenn27]

Nice coverage so far--:thanku:
-a darn shame you have to go back and do something should have been done right to start with///while in there--make sure and clean/fix all those electrial connections in the earlier pictures!:fing32:

I'll follow this all way thru--you have a nice piece of equipement there!!

glenn

 

[Zippez]

How does one go about removing the center pin? Just pull it out with vice grips? When "pressing in" a new one, should I tap it in using a rubber mallet? The way I interpret the manual I can remove and install a new centerpin without replacing the camshaft, is this correct?

Have you got this far yet? While I have never pulled the governor cup on my 520H, all the Onan manuals I have read state that the pin is essentially permanent and serviced only with the cam shaft as an assembly. I know the parts list shows a number for the pin but the service docs state the pin cannot be removed without damage. If it is that tight for removal, one can imagine the force that is going to be needed to install. Might get ticklish.
Have you pulled the governor cup/hub/balls and checked the 3/4" pin length dimension?

As an aside, for some extra information and cross reference, download the Onan manual available her on MTF. It is in the library and for a John Deere but has a completely different text and illustrations than the Toro manual. I do not know which manual you are using, but a second opinion is always nice!

John Deere Onan Manual

Please keep us informed! Interesting job!

 

[motox25]

Wow thanks that is a really useful manual I'm a visual person so the pics explain it well. After several attempts of trying to remove the pin I checked with some mechanics, it seems that one way to get it out would be to heat the pin to ease in removing it. The way my Onan manual explained it was that the pin was an easily removable component that could be replaced if it didn't fit to specs. Not exactly the case here. I'm just in the process of reassembling the engine and honestly I'm probably going to end up selling the tractor. I moved and have no need for a large tractor like this and someone with the right tools and experience could repair it fairly easily I'm sure.

 

[motox25]

While reassembling the engine I found a few more surprises, my crankshaft gear teeth have some damage to them near where the oil pump gear meets it on the outer edge. While turning the engine over by hand the gears turn correctly but I have no idea why or how the teeth got damaged. Again, by the time I got ahold of the tractor another mechanic put in a new set of rings and head gaskets. The engine seems to run fine with the exception of the governor issues. The tractor didn't seem to have any excessive vibration that I could tell before I disassembled it. I'm still seriously considering selling the tractor due to it being too large for my needs, but I realize how well made this machine is especially after working on it and hate to sell it for a smaller tractor that isn't as well made.

So, I am in need of some advice, here are the issues with the engine:

• Governor doesnt work properly
• Crankshaft gear teeth damaged
• Engine missing one "foot" (This doesn't seem to affect performance)

The engine has been recently rebuilt with a new set of rings, new head gaskets, new gear case gasket, new ignition module, new coil and new seals. I've looked at repower engines but I can't justify spending $1700+ for a new engine especially since the tractor is too large for my smaller yard.

 

[jusjeepn]

If you didn't live so far away, I'd offer an even trade on a nicely repainted 16 Auto

but it's a mite bit to far for me to travel!

 

[boomers_influence]

motox25.
after reviewing your pics, (very nice)i see that the flyball ring is missing the
tang that fits into the slot in the cam gear.
this is the cause of your governor problems.
thank you boomer
p/s the used onan parts guy

 

[Cole's dad]

I had a similar problem on a 520 w/ 109 hours. It would run and race. No governing. I opted to take it my local shop. Turns out that there was small clip on the linkage to the carb. Without it the linkage slid in to far and put the machine at full throttle. The rod should just have the tip of the rod sticking into the butterfly valve on the carb. I hope this helps.