K91R Auction Buy

[PWL216 1,092]

I was the winning bidder on a pump powered by a Kohler K91R engine. Based on its specs it’s a 1961. I don’t really have a need for it at the moment, but couldn’t pass it up. Here’s what I found about the K91…

 

• Model: Kohler K91
• Spec Number: 31504A
• Serial Number: 3019680
• Horsepower: ~4 HP
• Shaft Orientation: Horizontal (most likely, based on spec)
• Year of Manufacture: 1961

 

About Spec Number 31504A

 

Kohler’s spec number identifies the exact configuration of the engine — including shaft size, PTO options, mounting patterns, and whether it’s for a tractor, generator, or industrial use. While full public spec decoding guides are rare, the “A” suffix usually designates a factory revision or minor configuration changes.

 

Spec 31504A is known to have been used on early Wheel Horse tractors, most likely models like:

 

• RJ-58
• RJ-59
• Suburban 400 or 550

 

 

 

[oliver2-44 10,711]

Great buy!  
Interesting diaphragm pump. 

[ebinmaine 72,611]

Neeeeaaatt.  

 

Cute little tires too.  

[Ed Kennell 41,943]

Great find.  Any data on the pump capacity?

[PWL216 1,092]

1 minute ago, Ed Kennell said:

Great find.  Any data on the pump capacity?

@Ed Kennell Hi Ed. I pick it up Monday and it comes with the manual. Will know then. I was wondering if I should keep the whole thing together or just pull the engine, since I don’t need a pump. Thoughts on that?

[PWL216 1,092]

18 minutes ago, oliver2-44 said:

Great buy!  
Interesting diaphragm pump. 

@oliver2-44 Thx. Paid a whopping $10.90 for it

[Ed Kennell 41,943]

6 minutes ago, PWL216 said:

@Ed Kennell Hi Ed. I pick it up Monday and it comes with the manual. Will know then. I was wondering if I should keep the whole thing together or just pull the engine, since I don’t need a pump. Thoughts on that?

It would make a great display piece for a tractor show.     Maybe pumping water up to a small flume that operates a small waterwheel that turns a fan, ice cream churn, etc.

Edited Friday at 11:32 PM by Ed Kennell

[ebinmaine 72,611]

4 minutes ago, Ed Kennell said:

It would make a great display piece for a tractor show.     Maybe pumping water up to a small flume that operates a small waterwheel that turns a fan, ice cream churn, etc.

 

Seconded.  

[Chris G 3,356]

I would say use it as a display piece as well. Chances are that the end of the crankshaft has a star style end on it. Due to the gear reduction on it. So to use for a RJ or suburban you would probably have to change crankshaft. I attached a photo of what I mean by the different end on the crankshaft. But besides all that I'd also say it's a pretty cool find 

Edited Saturday at 01:08 AM by Chris G

[oliver2-44 10,711]

That type of pump should be able to pump a slurry, cement grout, mud. 

[oliver2-44 10,711]

21 hours ago, PWL216 said:

@oliver2-44 Thx. Paid a whopping $10.90 for it

That’s almost disgusting 😂

Help us feel better and tell you had to spend a lot on gas or something going to pick it up!

Edited Saturday at 08:32 PM by oliver2-44

[953 nut 59,918]

12 hours ago, oliver2-44 said:

Interesting diaphragm pump. 

We called the mud pumps, they were great for removing groundwater from a trench before pouring a footer.