Moving from an 1845 to a 425

[KMA]

The EH72 EFI engine helps with cold weather starting... but doesn't cure it in my experience. It probably can start reliably around 15 degrees colder than the carbureted version, but from what I've read it still doesn't quite match what the older Kohlers could do.

 

[marrt]

Guys,

I haven't had a chance to call PT yet. Will try to find time tomorrow and will report back.

Tom

 

[marrt]

On a related topic...anyone know the largest size wheel motor that will fit in the standard PT motor mounts? I suspect the motor mount is sized for the specific motor and, therefore, any change will require the motor mount be adapted. However, this might not be too expensive. In the last 14 years of posts, I remember this topic or a related version being discussed many times but don't remember the results. Time to warm up the search engine I guess.

 

[Marks481]

At some point I am going to purchase a new 425. (sooner than later) just wish they would give you an option.

Buy the PT425 and a Robin 28 EFI ($1800). Swap it out and ebay the Robin 25. Would cost more than if you bought it set up that way.

KMA did it to his PT422, didn't sound too hard:

http://www.tractorbynet.com/forums/power-trac/202389-pt422-engine-swap-completed-pics.html

 

[Gravy]

Marrt,

I've Googled this. If the White Hydraulics website specs for the CE series and my measurements are to be trusted, there should just be room in the wheel motor boxes to substitute a 16.8 cu in/rev motor for the stock 14.2 cu in/rev motor. At worst, a little shimming may be required.

 

[Gravy]

Buy the PT425 and a Robin 28 EFI ($1800). Swap it out and ebay the Robin 25. Would cost more than if you bought it set up that way.

KMA did it to his PT422, didn't sound too hard:

http://www.tractorbynet.com/forums/power-trac/202389-pt422-engine-swap-completed-pics.html

I've Googled this too. If we can trust the Subaru Robin website power curves for the EH72 series, the EFI version makes nearly all of it's "extra" power simply by revving to 4000rpm instead of 3600. It actually makes less torque at 2500rpm than the carbureted version.

FWIW, I've been running my 2004 carbureted EH72D at 4000 RPM for at least the last 8 years since I realized that my engine warranty was thoroughly voided by the air filter failure that deposited at least 1/8" of dust in the intake manifold. The engine has made it over 1100 hours now without blowing up and pulls a good bit harder than it did at 3600 RPM. As far as I can tell, the EFI version probably starts better in cold conditions and may use a bit less fuel. I'm not sure there is a noticeable difference in power at 3600 RPM.

 

[MossRoad]

On a related topic...anyone know the largest size wheel motor that will fit in the standard PT motor mounts? I suspect the motor mount is sized for the specific motor and, therefore, any change will require the motor mount be adapted. However, this might not be too expensive. In the last 14 years of posts, I remember this topic or a related version being discussed many times but don't remember the results. Time to warm up the search engine I guess.

You ever read the posts by jd-beach? I believe he paid Power Trac to install larger wheel motors from a 1430 onto his 425. That cut the top speed way down, but he put large tires (for sand flotation) on it to bring the speed back up. Ingenious!

 

[MossRoad]

The Kohler lugs pretty hard at starting in cold, like 10 degrees or colder. It has to with all of the cold hydraulic oil in all of those pumps. Frankly, I'm amazed every time it starts in those cold conditions. I can hear it turning at what I would estimate to be maybe 50-60 RPM with the starter.... that cold metal on metal whump....... whump..... whuuuhmp about 10-15 times before a pop. It scary! But it starts most of the time.

 

[KMA]

I agree about the power curve of the EH72 vs EFI version... virtually the same is my guess. Of course, I was coming from the EH65 so I did noticed a slight increase. If PT would swap in the EFI at the factory for a nominal fee, I'd do that. If not, I don't know if it'd be worth the effort and cost to swap it immediately after purchase. At that point, I might look for something more "exotic" (e.g. diesel, or liquid cooled).

Moss, the Robin acts the same way in the scenario you've described... except the Kohler will turn over for whatever reason and the Robin won't.

 

[MossRoad]

I wonder what the voltage coming out of the coils on the Kohler VS the Robin are? And what spark plugs both are using? Don't have time to check that stuff for a few weeks myself, sorry.