Pony Motor Problems

It's been a while since I took one off, but parts book lists 8 nuts and lockwashers around the base. then there is a water return at the top of the engine and the exhaust manifold connection to the heat pipe/intake manifold of the diesel. Be careful of the air filter pipe on top, it's easy to break them if the engine tips over etc. Also easy to strip the bolts that hold it down on the carburetor and the crankcase breather stack.

Of course you must drain the oil from the pony (drain plug is on right side of diesel engine's clutch housing near the breather, oil fill and dipstick and also drain the radiator through the valve in lower radiator pipe by loosening the 3/4" hex head valve stem accessible through the hard nose brace on left front corner of tractor). Even if there is a belly pan on it, the stream of coolant from the drain will go out the hole in the belly pan put there for that purpose. Might have to clear the hole before you turn the coolant loose if the belly pans look like most of them do.

I expect you will soon hold the opinion that working on a pony motor is pretty expensive compared to converting to a direct electric start, but it all depends on what you have around for spares and whether your clutch housing is already bored for a starter.

[quote="ccjersey"]It's been a while since I took one off, but parts book lists 8 nuts and lockwashers around the base. then there is a water return at the top of the engine and the exhaust manifold connection to the heat pipe/intake manifold of the diesel. Be careful of the air filter pipe on top, it's easy to break them if the engine tips over etc. Also easy to strip the bolts that hold it down on the carburetor and the crankcase breather stack.

Of course you must drain the oil from the pony (drain plug is on right side of diesel engine's clutch housing near the breather, oil fill and dipstick and also drain the radiator through the valve in lower radiator pipe by loosening the 3/4" hex head valve stem accessible through the hard nose brace on left front corner of tractor). Even if there is a belly pan on it, the stream of coolant from the drain will go out the hole in the belly pan put there for that purpose. Might have to clear the hole before you turn the coolant loose if the belly pans look like most of them do.

I expect you will soon hold the opinion that working on a pony motor is pretty expensive compared to converting to a direct electric start, but it all depends on what you have around for spares and whether your clutch housing is already bored for a starter.[/quote]


I managed to remove manifolds off top and gas tank and the coolant connector, and all ten bolts/nuts at bottom. I can not get it to move at all with moderate pry pressure. I guess there is nothing connected between the two engines, except at bottom--the space is tiny and full of dirt. What else could be holding her, or is it just stuck good after 50 some yrs. My D6 serial # is 9U- 21332, I think manufactured early 1960's?
Eventually, I'll need a overhaul manual. What is best reference? Two of my brothers are licensed mechanics, so my labor cost will most likely be in terms of beer. Thanks for the reply.

[quote="ccjersey"]It's been a while since I took one off, but parts book lists 8 nuts and lockwashers around the base. then there is a water return at the top of the engine and the exhaust manifold connection to the heat pipe/intake manifold of the diesel. Be careful of the air filter pipe on top, it's easy to break them if the engine tips over etc. Also easy to strip the bolts that hold it down on the carburetor and the crankcase breather stack.

Of course you must drain the oil from the pony (drain plug is on right side of diesel engine's clutch housing near the breather, oil fill and dipstick and also drain the radiator through the valve in lower radiator pipe by loosening the 3/4" hex head valve stem accessible through the hard nose brace on left front corner of tractor). Even if there is a belly pan on it, the stream of coolant from the drain will go out the hole in the belly pan put there for that purpose. Might have to clear the hole before you turn the coolant loose if the belly pans look like most of them do.

I expect you will soon hold the opinion that working on a pony motor is pretty expensive compared to converting to a direct electric start, but it all depends on what you have around for spares and whether your clutch housing is already bored for a starter.[/quote]


I managed to remove manifolds off top and gas tank and the coolant connector, and all ten bolts/nuts at bottom. I can not get it to move at all with moderate pry pressure. I guess there is nothing connected between the two engines, except at bottom--the space is tiny and full of dirt. What else could be holding her, or is it just stuck good after 50 some yrs. My D6 serial # is 9U- 21332, I think manufactured early 1960's?
Eventually, I'll need a overhaul manual. What is best reference? Two of my brothers are licensed mechanics, so my labor cost will most likely be in terms of beer. Thanks for the reply.

The Serviceman's Reference book Form FE30238-X (x may be different revisions, I have the A revision) Titled "Caterpillar Diesel engines (4 1/2" bore 6 cylinder) D318 industrial, D318 electric set etc etc etc" has all the procedures and specifications.

Bet the last fastener is down in the crack between the diesel and the pony or underneath one of the cylinders where it's hard to see.

Check Ebay and Amazon, used book sites etc or order from CAT
http://www.cat.com/cda/layout?m=90800&x=7 is the listing. I believe there was a direct number, but I do not have it, you can order through your CAT dealer.

The D6 pony has eight studs/nuts and three cap screws through the mag cover into the clutch housing for a total of 11 fasteners.

The magneto looks to be bolted to back of pony motor up higher than clutch just below the compression release lever. I'm still looking for other fasteners. fred

The D6 pony has eight studs/nuts and three cap screws through the mag cover into the clutch housing for a total of 11 fasteners.