What repacement engine for the Robin?

BAGTIC · Feb 2, 2009

I have not been on here for a long time but I need some suggestions.

What engine would be a suitable replacement for my piece of Robin crap?

Any opinions on the Kohlers amd B&S models?

Do most small twin engines in this size range have common base mounting dimensions or would it be necessary to fabricate new mounts?

I am assuming that a engine switch might also involve new hydraulic hoses, Electrical harnesses, etc.

Any reason the engine compartment on the PT425 could not be deepened by welding in an extension for an engine that fit length and width but was just a little too tall?

Now the reason I have not been on recently.

About six months ago my engine froze up and could not be repaired. Before taking it out the last time I filled the tank and the oil. It has always had the filters changed regularly, I buy them by the dozen.

This is the same engine whose alternator went out just before the warrantee expired.

I have been SIX months trying to BUY a replacement engine. No luck. I have been told there are none in stock in the USA. There may, MAY, be ONE in Japan but they have been checking for 2-plus weeks and I still don't have an answer.

I missed the late summer mowing last year and the weeds went to seed. I missed the fall forage (rape, turnips, etc) planting and now I am having to buy feed for both my cattle and goats.

We are just coming out of a major ice storm without power, water, etc. Without the tractor my winter firewood supply is down to about one week. I have plenty in the fields but can not get it out without the tractor.

The storm hit us hard. I had 2-plus miles of new woven fencing, feeders, gates and cattleguards installed last summer. Now I have nothing but my bare hands and a chainsaw to clean the roads, fences, etc. I am 67 years old with a bad heart and rheumatoid arthritis so I am going to end up hiring the work done. It hurts when one is living on social security. I know now, too late, that I should have bought a real tractor, not a toy, in the first place.

You can be sure that this is the last time I will buy Japanese.

'Pissed in the Ozarks'

SnowRidge · Feb 2, 2009

BAGTIC, I am very sorry to hear of your engine troubles. I have seen 25 HP Robins listed for sale on the web. There was no indication that they were in short supply. Most of these small engines are available in myriad configurations of the same type and horsepower, each with a slightly different part number and configured for a particular purpose. I wonder if it is the specific model used in the Power Trac that is in short supply. Perhaps a general replacement engine might work. Most manufacturers have one model that can be used to replace a whole slew of special order engines. I know Kohler does.

If you are going to convert to a new engine, the easiest conversion would probably be to a horizontal shaft 25 - 27 HP Kohler, since that is what PT used prior to going with the Robins. A more or less exact replacement for the 25 HP engine in my PT-425 is around $1495 through Internet sources.

You would still need to source mounting brackets and engine mount, all of which are available from Power Trac, but of course they are not cheap. The correct Kohler has an SAE mount pattern, and mounts for the pumps should be available from other sources. The Kohler will drive stuff off of both ends, unlike a lot of engines. In fact, my PT-425 has the tram pump on one end of the motor, and the other pumps on the opposite end.

Kohlers come with an engine wiring harness. The PT chassis harness in the Robin equipped machines is probably slightly different than the Kohler powered machines. A little electrical knowledge would go a long way in making sure things were hooked up properly.

Still, I think it would be a bit of a job. There are likely enough differences between the old Kohler machines and the new Robin machines that it would take someone with some mechanical expertise to do it right. If you don't have the necessary mechanical ability, and I have no idea whether or not you do, a new Robin may still be your best bet.

SpringHollow · Feb 3, 2009

There is the PT429 for sale in the classifieds - has a new engine.

Ken

bjustice · Feb 4, 2009

There is an engine (Robin) on ebay item 280224374013 looks like an exact replacement. The lister (not me) could tell you. $1695.00 seems high--but it is avail.
Bill

bjustice · Feb 4, 2009

Looking at the store above there are listings for B&S and Koehler as well as Honda. They should be able to tell you which will bolt up if you REALLY don't want another Robin.

BAGTIC · May 19, 2009

STILL LOOKING FOR A REPLACEMENT ROBIN ENGINE FOR MY 425.

The engine plate on the old engine says EH720DS00116306

BAGTIC · May 19, 2009

OOPS! Hit wrong key.

Recently someone mentioned buying a replacement through internet.

It may have been this source? www.brandnew engines.com

Their ad says EH720DS1211. If someone used this engine on PT425 did it work?

If you found another model that drops in PLEASE let me know.

ToolcatWonka5610 · May 19, 2009

Go to smallenginewarehouse.com if you haven't already. They have Tons of small Gas engines from many different brands. You should see all the Kohler engines they have!

IMO if I was gonna repower a PT-425, I'd go with the Kohler 26hp Fuel Injected Horizontal Shaft Engine. I do not like carbureted engines. I'm a Diesel person, but I'd go with Fuel Injected Gasoline if I had to.

Marks481 · May 19, 2009

BAGTIC said:
The engine plate on the old engine says EH720DS00116306

From the Robin parts manual:

Robin engines are identified by MODEL, SPECIFICATION, and CODE NUMBER. For each model there may be many different versions called specifications. Each specification will be unique in some way. The difference may only be the paint color or it may have a different type of PTO or some other significant difference.

In order the identify the correct service part number, it is important to confirm the specification and code numbers for your engine. The specification and code number together are know as the PRODUCT NUMBER.

The Product Number Label has a 15 digit alphanumeric string that consists of the SPECIFICATION (SPEC) number (11 digits) and the CODE number (4 digits).

You engine is MODEL #EH72, Spec #EH720DS0011, Code #6306.

Brand new engines sells four different types of EH72 engines: EH720DS1211, EH720DS0430, EH720DS0021, EH720DS0011 (the one you need). Don't buy the wrong one.

Your engine's code #6306 (the last four digits) simply identifies incremental updates to improve/update the product, but should not affect the use. So if you get an engine with a serial number of EH720DS0119999, it will still work for you.

I would buy this one for $1595:

Robin Subaru V-Twin Engine 25 hp OHV EH72 1-7/16" x 4.37" ES #EH720DS0011

Marks481 · May 19, 2009

ToolcatWonka5610 said:
IMO if I was gonna repower a PT-425, I'd go with the Kohler 26hp Fuel Injected Horizontal Shaft Engine.

OK, I will have to change my vote. The Kohler might not be a drop in replacement like the Robin, but it does have the same size shaft on it, so it might work. I am younger and don't mind extended projects; YMMV. The Kohler is 1.5" longer then the Robin, so it might be a tight squeeze.