New MF12 Owner - Engine & Trans Questions.

[Road Warrior]

Hello,

I just got a 1970 MF12. The engine runs but needs rings and seals, maybe more. The hydro trans works but slips pretty good. Otherwise it's in great condition for a 38yr old machine.

- If I just replace the engine, is there such a thing as an adapter so I can use the 1-1/8" engine pulley on a 1" shaft? ...or are there 1" pulleys that would match the sizes and spacing of the OEM one?

- Is the hydro drive easy to rebuild? I have the service manual. Is there a specific model number related to it? I may inquire about sending it out to be rebuilt but am unsure who might be familiar with fixing them.

Thanks,
Steve

[bontai Joe]

:Welcome1: Glad to have you here. Is the motor in your tractor a Kohler? And do you know what hydro you have in it? Possibly a Sundstrand?

[olcowhand]

They do make such spacers, but not sure where to find them. Wheel Horse used them on the GT14, or at least on the one I had. It had a thin sleeve adapter which had a groove to allow the key to stick through to hold pulley.

[Road Warrior]

:Welcome1: Glad to have you here. Is the motor in your tractor a Kohler? And do you know what hydro you have in it? Possibly a Sundstrand?

It has a tecumseh HH120. I'm thinking a ring/piston kit may revive it. It smokes bad on start up and gets better as it warms up. I have not measured compression, but I don't think valve seals are an issue. It does take some serious CCA to turn over. A healthy car battery isn't enough, I had to hook it up to my 1200 CCA marine battery and even then it takes a second to start turning. I'm kind of leaning toward the easy way out and dropping in a new engine.

I'm not sure what hydro it has. I might inquire with these guys about rebuilding: http://www.hydrostatic-transmission.com/
I'm just wondering how much $$$ that will cost.

Thanks,
Steve

[Road Warrior]

They do make such spacers, but not sure where to find them. Wheel Horse used them on the GT14, or at least on the one I had. It had a thin sleeve adapter which had a groove to allow the key to stick through to hold pulley.

I'm wondering if this is what I need:
http://www.smallenginewarehouse.com/product.asp?PN=Sleeve-1-118x3&desc=Misc+Engine+Parts+Bronze+sleeves+1+I+D+x+1+1+ 8+O+D+x+3+total+length+also+includes+2+of+1+4+x+5+ 16+key+stock

If so, it will save much grief. I will only put 50hrs on this thing a year so I don't need an expensive commercial engine with the 1-1/8” shaft. 1” seems the most common in the low end 13-16HP choices. I'd also like to get the HH120 restored so one day I can return the tractor to it's original state.

Thanks

[olcowhand]

If you don't push the brake pedal "full in" while cranking, the starter is dragging the hydro also. They'll crank twice as fast with pedal down, which loosens the idler on the hydro belt....if all is as it should be.

[olcowhand]

Yep, those sleeves are exactly what you need. The key included is extended height to allow for the thickness of the sleeve. The stock key would be 1/4" square.

[Road Warrior]

If you don't push the brake pedal "full in" while cranking, the starter is dragging the hydro also. They'll crank twice as fast with pedal down, which loosens the idler on the hydro belt....if all is as it should be.

That's good to know. That is the likely reason it displayed so much trouble turning over.

[Road Warrior]

Yep, those sleeves are exactly what you need. The key included is extended height to allow for the thickness of the sleeve. The stock key would be 1/4" square.

I just ordered the sleeves. Now to choose an engine.

[Smog]

I just ordered the sleeves. Now to choose an engine.

the chinese clone of the honda GX390 will fit without too much trouble

a 16hp stroked and bored to 420cc chinese GX390 is a cheap replacement and most of them are trouble free.

the 10hp diesel yanmar (or the chinese copy) will also fit but don't be fooled by the low hp; it's a very strong engine that won't die sputtering under load like a gasoline engine.

[Road Warrior]

the chinese clone of the honda GX390 will fit without too much trouble

a 16hp stroked and bored to 420cc chinese GX390 is a cheap replacement and most of them are trouble free.

the 10hp diesel yanmar (or the chinese copy) will also fit but don't be fooled by the low hp; it's a very strong engine that won't die sputtering under load like a gasoline engine.

I've been seeing more and more of those around. I looked at Duropower and just recently saw Carrol Stream Motor Co. I'm thinking about their 16HP for $355 shipped. I kind of want one out of curiosity, seems kind of cheap for a 16hp w/ electric start.

http://cgi.ebay.com/16HP-ELECTRIC-START-GAS-ENGINE-16-HP-HORIZONTAL-SHAFT_W0QQitemZ170219094697QQihZ007QQcategoryZ2952 0QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I'm a fan of diesels too, I wonder how many hours a WVO powered clone would last in a generator?

[Smog]

I've been seeing more and more of those around. I looked at Duropower and just recently saw Carrol Stream Motor Co. I'm thinking about their 16HP for $355 shipped. I kind of want one out of curiosity, seems kind of cheap for a 16hp w/ electric start.

http://cgi.ebay.com/16HP-ELECTRIC-START-GAS-ENGINE-16-HP-HORIZONTAL-SHAFT_W0QQitemZ170219094697QQihZ007QQcategoryZ2952 0QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I'm a fan of diesels too, I wonder how many hours a WVO powered clone would last in a generator?

I've seen 2000 hours @ 2500 to 3000 rpm burning used hydraulic oil, used motor oil and heated veggie oil; then the balancer shaft broke.

[Road Warrior]

I've seen 2000 hours @ 2500 to 3000 rpm burning used hydraulic oil, used motor oil and heated veggie oil; then the balancer shaft broke.

At least that's not too hard of a fix but it must have been a little disappointing.


I pulled the trigger on the Chinese 16HP. I got it mounted and it fired right up. I still need to swap the pulley. It appears to have been damaged and poorly welded back together. It will need some care to remove from the HH120. It appears the muffler sticks out about 1cm too far as well. I'll need to explore other options.

[Smog]

At least that's not too hard of a fix but it must have been a little disappointing.


2000 hours using free hours in a 500$ engine is quite cheap.

[Dad0850]

Welcome to the forum, Road Warrior! :Welcome1: Glad to have you join us!