repower

[johara1]

Hi guys it's been a long time,but i had nothing going wrong. Now i think i would like a new engine,the robin 25 would be simple but the kohler may be a better deal.The problems are the wiring,has anybody did this before?the fab. of the mounts is no big deal but the wiring change from the robin 22 to the kohler has me stumped......jim

 

[J_J]

Hi guys it's been a long time,but i had nothing going wrong. Now i think i would like a new engine,the robin 25 would be simple but the kohler may be a better deal.The problems are the wiring,has anybody did this before?the fab. of the mounts is no big deal but the wiring change from the robin 22 to the kohler has me stumped......jim

The change over should not be a problem. Each Kohler engine should include an owners manual, that has the wiring diagram for the electrics. You should use Kohler's ign switch. so you don't burn up the wiring. There are a lot of those similar ign switches around and if used with the wrong switch, bad things could happen. The one on your machine might be the same, but I would test the configuration for the switch and plug.To bad you can't use a Kohler 25 HP vertical engine, you can get them for about $700.00.

 

[johara1]

JJ,what about all the other wiring on the tractor? would it be the same? i would like to see a wiring diagram for the kohler,i have the one for robin.
i was thinking of getting a kohler with the controls and switch on it and just move it to the front.that way i wouldn't make a mistake.........jim

 

[MossRoad]

Hi guys it's been a long time......jim

Welcome back!

 

[J_J]

JJ,what about all the other wiring on the tractor? would it be the same? i would like to see a wiring diagram for the Kohler,i have the one for robin.
i was thinking of getting a Kohler with the controls and switch on it and just move it to the front.that way i wouldn't make a mistake.........jim

Jim.

I agree with your plan. Just make up a wiring harness from the motor to the front. Maybe 4 wires.

Go to the Kohler web site, and specify the engine, and I am sure you can download the manuals.

As far as all the wiring on the PT, there is probably a common point for the 12v accessories, and there is an accessories lug on the back of the Kohler switch.


http://www.kohlerengines.com/manuals/landing.htm

26 hp page 98 of 232.

There are other engines on this link, so go to the right and select the owners or service manusl for the engine you want.

 

[johara1]

JJ,sounds like a plan,thanks..
MR,do you have the wiring print for your 425? so i can compare it to my robin print? you know it's been a couple years,i'm retired looking for something to do like a big motor.....jim

 

[SnowRidge]

I think it would be a whole lot easier to install a new Robin and be done with it.

Kohlers are not trouble free engines. If you go to somewhere like http://www.lawnsite.com, you will find that they have their issues like all brands. The CH25s have a history of bad valve lifters and dropped valve seats. Mine has dropped a valve seat twice, once under warranty, and once on my nickel.

If I ever have to repower my PT-425, I won't switch engine brands. It's just too much work for no gain. The electrical hook up would be the easy part. Fabricating and/or locating and purchasing the various mounts, rigging the exhaust, checking and verify clearances, routing or rerouting hoses if necessary, would all be a real PITA. And there is always the possibility of making a serious mistake along the way that won't reveal itself until much later.

Now if the replacement engine was a diesel, that would be another matter. Then it would be oh so worth it.

 

[johara1]

SnowRidge, that may be true, i was thinking of the 25 hp robin if i go that route,but you still have the starting issue. i now keep it in a heated building in the winter. i guess thats not a issue anymore.......jim

 

[MossRoad]

JJ,sounds like a plan,thanks..
MR,do you have the wiring print for your 425? so i can compare it to my robin print? you know it's been a couple years,i'm retired looking for something to do like a big motor.....jim

I'll have to look. Its been many years since I looked in the PT supplied manual. Had no trouble, so no need to look. ( I'll regret saying that! )

I purchased manuals for my Kohler from a local engine shop.

 

[MossRoad]

I always wondered why you couldn't power it off of a belt drive instead of a direct connection to the engine shaft? That way, you could run it off of just about any engine available, like a Chevy 153 straight 4 from the 60s. Simple as simple gets and would last a lifetime in these machines.

 

[SnowRidge]

I always wondered why you couldn't power it off of a belt drive instead of a direct connection to the engine shaft? That way, you could run it off of just about any engine available, like a Chevy 153 straight 4 from the 60s. Simple as simple gets and would last a lifetime in these machines.

Yeah, water cooling and twice the size and weight of the Kohler or Robin is simple -- NOT. Of course, you could always mount it on top of the hood, cut a slot in the hood, and belt drive the sucker from above.

Actually, I think I saw something like that at a speed show years ago. No wait, that was a corvette powered bug-eyed Sprite. It couldn't corner, either.

 

[KentT]

Though I own a Kohler-powered PT-425, I think if I had a later model Robin-powered one with all the pumps on one end of the engine, that I'd consider using a Honda for a air-cooled repower over the Kohler...

I have never heard ANYTHING negative about Honda commercial-grade engines, and they power most of the small rental equipment on the market. Look at the cement mixers, etc., that get used all day for a living -- chances are, it's Honda-powered. If not, it's more likely to be a Kawasaki, instead of a Kohler, Briggs or Robin (in that order)...

Another major reason is NOISE -- Honda engines quietly purr....

I think with a Honda-powered PT, you'd probably notice the hydraulic whine more than the engine noise...

 

[SnowRidge]

Though I own a Kohler-powered PT-425, I think if I had a later model Robin-powered one with all the pumps on one end of the engine, that I'd consider using a Honda for a air-cooled repower over the Kohler...

I have never heard ANYTHING negative about Honda commercial-grade engines, and they power most of the small rental equipment on the market. Look at the cement mixers, etc., that get used all day for a living -- chances are, it's Honda-powered. If not, it's more likely to be a Kawasaki, instead of a Kohler, Briggs or Robin (in that order)...

Another major reason is NOISE -- Honda engines quietly purr....

I think with a Honda-powered PT, you'd probably notice the hydraulic whine more than the engine noise...

If it would fit, it might be worth the effort. I've never had any problems with any Honda engine. I can't say that about any other brand. If they just made a diesel . . . .

 

[J_J]

If it would fit, it might be worth the effort. I've never had any problems with any Honda engine. I can't say that about any other brand. If they just made a diesel . . . .

I believe that Kohler makes a diesel. Liquid cooled, and air cooled.

 

[SnowRidge]

I believe that Kohler makes a diesel. Liquid cooled, and air cooled.

Yes, Kohler has some diesels. Whether or not any of them would be suitable replacements is another question. I have no idea how successful they are as a product line.

 

[johara1]

Guys, what about a 31 hp. briggs&stratton? can you get a stub shaft for them,like kohlers.
mine has the pumps on both ends........jim

 

[woodlandfarms]

Maybe too much HP? I still think the Honda engine would be way cool.

Although you are talking gas, may not be as much of an issue...

 

[3238dpw]

That 31 hp Briggs would be cool. I talked to Scarg (remember the 429 Kawi engine http://www.tractorbynet.com/forums/power-trac/110268-pt-429-project.html ) and he said he had to do a ton of reserch to finally find an engine that could fit down in the tup of the 400 series PT. He said not too many would fit and the Kawi just fit. I am only assuming but I think that engine would fit that catagory of not fitting.

 

[johara1]

3238dpw, i was hoping it would work,but i have pumps on both ends. so i need a stub shaft,plus it about 2.5" longer than the robin.......jim

 

[RegL]

Though I own a Kohler-powered PT-425, I think if I had a later model Robin-powered one with all the pumps on one end of the engine, that I'd consider using a Honda for a air-cooled repower over the Kohler...

I have never heard ANYTHING negative about Honda commercial-grade engines, and they power most of the small rental equipment on the market. Look at the cement mixers, etc., that get used all day for a living -- chances are, it's Honda-powered. If not, it's more likely to be a Kawasaki, instead of a Kohler, Briggs or Robin (in that order)...

Another major reason is NOISE -- Honda engines quietly purr....

I think with a Honda-powered PT, you'd probably notice the hydraulic whine more than the engine noise...

I don't have much experience with honda but have read that their larger engines, above 12hp or so, are not reliable like their smaller engines. Also, I went to Honda engines web site and could not find a horizontal shaft model over 20.5 hp.