720 pony

[johndeeregreg]

hi the pony that i got to convert my 720 back doesn't have a thermostat on it. the parts book shows it having one, the guy i got the pony from said it came off a 720.

is it possible they were using up old stock when the built them and it never had one or is it more likely some one put a pony off a 70 on that 720 it came off of? also is it going to affect anything not having one?

 

[BushogPapa]

Why would the Pony have a thermostat anyway...it is supposed to warm the BIG engine cooling system, as well as the Big engine's intake..??

Ron.

 

[Half]

Thermostat

 

[Rich Duane]

Greg,
All the starting engines had thermostats part number AF 2415 R, They help the engine warm up faster.

 

[Bob]

FWIW, the 70 parts catalog shows the thermostat started at serial #7034100.

The 720 parts catalog shows they ALL had thermostats.

 

[johndeeregreg]

should have stated its not just missing the thermostat, but rather there is no place for one, the manifold is one piece and there is no port in the water pump for that bypass line in the picture above that goes from pump to thermostat cover.

 

[Anonymous-0]

You have a pony off of an early 70. They did not have the thermostat. I would switch it. I would talk to the seller because you got one off of an early 70 pony. I bet it has the weak rods in it too....

 

[johndeeregreg]

do you know the number on the weaker rods?

 

[johndeeregreg]

mine has the f3300r connecting rods in it, which is the only casting number listed for the 720 ponys, its listed in the 70 book too, but there is another number rod listed for the 70 aswell

 

[BushogPapa]

May be so, but who runs the Pony that long..!!

I always allow mine to warm up before I throttle-up and start, but many don't at all..

Ron.

 

[Mike M]

Rods were all the same. They changed the size of the main bearing. Rear one IIRC ?

 

[Midnight flyer]

Not 100% sure but I think if its actually off a 720 there should be a brass serial number tag on it. I know there is a date they started adding them and think it was after they quit making those fine machines, JD70"s.