Switched out robin to kohler

[kmaz]

About a month or so ago my robin 25 with 560 hrs died.... aside from the hard starts in winter every problem it gave me was in the rocker/lifter area, this one was no different. Upon disassembly I found the valve guide on the exhaust valve starter side of motor literally cracked in half. Must of gotten loose I suspect from a heat related issue. Valve guides can still be found but it had wobbled around and widened the sleeve. I've had it with the robin so ordered a kohler ch730-3004. Installation was fairly straightforward. Only other new part I ordered for motor was new pt exhaust and a new lovejoy rubber spider thingy.( mine was a little worn.)
You can imagine my disappointment when all done couldn't get it to fire!! No spark!
Searched the forum but couldn't fine anything on wiring from robin to kohler.
Terry saved the day today. For others that may make the switch, on the pt harness there are 4 prongs with red, black, green, and blue.
Black is center top. Red is on one side by itself, and green and blue is on the other. Simply switch the green and blue wires on the connector. Green where the blue was and blue where the green was.
Sure enough...fired right up!
Thanks terry!
Kris

 

[MossRoad]

Very nice! :thumbsup:

 

[cqaigy2]

Good Job! I found the same problem with my swap from Robin's, so i can imagine your disappointment. :thumbsup:

 

[kmaz]

Good Job! I found the same problem with my swap from Robin's, so i can imagine your disappointment. :thumbsup:

I just read your thread with your engine replacement.. can't believe I missed your post on changing the wires! Doh!
One other thing I did was switch the mechanical fuel pump valve cover to the other side to get all the fuel hoses away from the muffler. To my surprise it was a perfect swap.surprised pt doesn't do that.i wasn't sure if it would make a difference with the fuel pump being mechanically driven by the exhaust rocker rather than the intake rocker on the other side.(shouldn't matter in my mind). I did have to reroute the line that feeds the carb to the other side.
Kris

 

[MossRoad]

You can gut the mechanical fuel pump, and use the hose fittings ports on the valve cover to power a $15 vacuum fuel pump, too.

 

[joshlee]

Way to go Kris. I hear good things about the Kohler engines working well with the PT-425.

Josh

 

[ldabe]

Can this swap be done on a PT 422?
Do you (KMAZ) have this project on a thread on this forum?
How much did the Kohler engine cost, if you don't mind?
Thanks.

 

[kmaz]

Sorry... I havnt been on. I did not do a seperate thread on the swap. The engine was around $1550 from OPE engines, and I would recommend them.
Kris

 

[ldabe]

Sorry... I havnt been on. I did not do a seperate thread on the swap. The engine was around $1550 from OPE engines, and I would recommend them.
Kris

Hi Kris, I need a new engine also.
I have a few questions if you don't mind.
Could you give me the web site URL for where you ordered your new engine? I am assuming it Was delivered to your home, correct? Was it a kholer 425? What year is your PT425?

Do you think this swap would also work for my PT422?

I have mine in the shop, they are telling me it needs a new engine (currently it has the 22hp Robin / Subaru). They said they talked to Power Trac and I could get another 22hp Robin from Power Trac. I don't want another Robin engine!

Besides the wiring harness was there anything else that needed modified or changed?

Thanks Kris.
Anyone else that wants to add a couple cents to this, please feel free. I need all the help I can get

 

[ldabe]

You can gut the mechanical fuel pump, and use the hose fittings ports on the valve cover to power a $15 vacuum fuel pump, too.

Hi MossRoad,
Since Kmaz has not responded yet, and I was wondering if you know of another way I might get in contact with him?
My PT422 needs to have an engine change also and I do not want another Robin/Subaru engine.
I am not real mechanically inclined, but can turn a wrench and I do have some common sense.
My PT422 is at a shop now, they are the ones that said it needs a new engine. They said they contacted Power Trac Company, and was told to replace with another Robin, which they would sell to the shop, but as I said, I do not want another Robin engine.
Also, the shop is quoting me (if I went with another engine, and for them to do the R&R) $3500.
I thought I read by Kris (Kmaz) that he replaced his engine for $1550.
So over $2000 for the shop to do it seems a bit outrages to me, what do you think?
(Plus, again, I don't want another Robin engine.)
Thanks
Abe

 

[TractorGuy]

Hi Kris, I need a new engine also.
I have a few questions if you don't mind.
Could you give me the web site URL for where you ordered your new engine? I am assuming it Was delivered to your home, correct? Was it a kholer 425? What year is your PT425?

Do you think this swap would also work for my PT422?

I have mine in the shop, they are telling me it needs a new engine (currently it has the 22hp Robin / Subaru). They said they talked to Power Trac and I could get another 22hp Robin from Power Trac. I don't want another Robin engine!

Besides the wiring harness was there anything else that needed modified or changed?

Thanks Kris.
Anyone else that wants to add a couple cents to this, please feel free. I need all the help I can get

Why not go electric?

PT-422 Electric Conversion.......Done!

I have not posted in some time, but I thought the group might be interested in this. Electric conversions have been talked about on here a few times. Here is my successful conversion story. I have now gone through two engines in my 422, the factory engine threw a rod mowing on slope and the...

www.tractorbynet.com

To be honest I would find a Briggs conversion before putting a Kohler in anything.

Engine Repower Help

shop.briggsandstratton.com

 

[cqaigy2]

This is what i used on my 422. If my search capabilities were better, i'd post the thread too.

Equipatron | Home

Equipatron is a leading e-commerce provider of power-equipment, small engines, replacement parts, hydraulics and unparalleled customer service. Shop our wide selection of well-known brands today.

www.equipatron.com

Kohler CH730-3208 Horizontal Engine​

KOH-PA-CH730-3208​

Grand Total (Incl.Tax)​

$1,526.95​

 

[MossRoad]

Hi MossRoad,
Since Kmaz has not responded yet, and I was wondering if you know of another way I might get in contact with him?
My PT422 needs to have an engine change also and I do not want another Robin/Subaru engine.
I am not real mechanically inclined, but can turn a wrench and I do have some common sense.
My PT422 is at a shop now, they are the ones that said it needs a new engine. They said they contacted Power Trac Company, and was told to replace with another Robin, which they would sell to the shop, but as I said, I do not want another Robin engine.
Also, the shop is quoting me (if I went with another engine, and for them to do the R&R) $3500.
I thought I read by Kris (Kmaz) that he replaced his engine for $1550.
So over $2000 for the shop to do it seems a bit outrages to me, what do you think?
(Plus, again, I don't want another Robin engine.)
Thanks
Abe

All I could tell you is try sending him a PM. I have no way of contacting any members of TBN other than that.

As for swapping out an engine...

I'm gonna guess the Robin and Kohler's have different dimensions. Footprint would require different mounts. Shaft sizes would require different lovejoys. Shaft lengths. Length of engines. Length of pump mounts. Could get quite complicated. If you go Robin to Robin, I cannot see why a shop would charge that much. It's something I would do at home if it's a direct swap. But if you switched Robin for Kohler, then I imagine it would involve some fabrication and labor and that all adds up to $$$$.

 

[ldabe]

All I could tell you is try sending him a PM. I have no way of contacting any members of TBN other than that.

As for swapping out an engine...

I'm gonna guess the Robin and Kohler's have different dimensions. Footprint would require different mounts. Shaft sizes would require different lovejoys. Shaft lengths. Length of engines. Length of pump mounts. Could get quite complicated. If you go Robin to Robin, I cannot see why a shop would charge that much. It's something I would do at home if it's a direct swap. But if you switched Robin for Kohler, then I imagine it would involve some fabrication and labor and that all adds up to $$$$.

MossRoad, thanks for your quick reply. What you state about the swap, I thought the same, that “it would involve some fabrication”. That’s why I wanted to speak with Kmaz, because what he wrote about his swap SEEMED (my take, my presumption) as if it was a swap for swap with no “fabrication” whatsoever. If he had done so, there was no implicit in his thread. So that is why I would really like to speak to him. I am not sure how to do a PM, could you direct me on that? As always, thank you and others of the forum that help on so many different things.

 

[ldabe]

Why not go electric?

PT-422 Electric Conversion.......Done!

I have not posted in some time, but I thought the group might be interested in this. Electric conversions have been talked about on here a few times. Here is my successful conversion story. I have now gone through two engines in my 422, the factory engine threw a rod mowing on slope and the...

www.tractorbynet.com

To be honest I would find a Briggs conversion before putting a Kohler in anything.

Engine Repower Help

shop.briggsandstratton.com

TractorGuy, thinks for your input. I would love to go electric but I would need you to walk me through everything! Tell me you are up for the challenge and I will GO FOR IT! Also, why would you go with a B&S over a Kholer engine if you don’t mind me asking?

 

[ldabe]

This is what i used on my 422. If my search capabilities were better, i'd post the thread too.

Equipatron | Home

Equipatron is a leading e-commerce provider of power-equipment, small engines, replacement parts, hydraulics and unparalleled customer service. Shop our wide selection of well-known brands today.

www.equipatron.com

Kohler CH730-3208 Horizontal Engine​

KOH-PA-CH730-3208​

Grand Total (Incl.Tax)​

$1,526.95​

Cqaigy2, how much “fabrication” was needed for you to swap engines? Thanks.

 

[marrt]

I thought PT was now offering a kit to make these swaps easy....

 

[cqaigy2]

I thought PT was now offering a kit to make these swaps easy....

PT does have some parts that make it possible to do the swap with little no fabrication. I found my thread where i ended up changing out my robins to kohler.
If you have questions, i'll do my best to answer them. Check out the thread below.

422 need to tow out of woods

Hi all, I need to tow my 422 a short distance and my documentation does not match the pump well enough for me to be sure what to loosen. I'll include a couple picts here. Maybe the red arrow indicates something to loosen up? :) Thanks in advanced!

www.tractorbynet.com

 

[ernemats]

When I changed my engine on my 422 , I talked to Terry and he said they would do it and the price didn't seem that bad(can not remember what it was)I ended up swapping Robin to Robin which I had purchased several years before used.

 

[johara1]

I changed out a 422 to a 25 HP. and even change to higher torque wheel motors and it is no big deal, The results were were not as much as I expected. I never had a issue in the winter with the Robin engines..... Jim