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