12 replies to this topic

[Petenpole]

OK friends, I am looking for advice and opinions. The 1855 engine is leaking oil and just doetn't seem to have the power it should. The original B48 engine bit the dust per the previous owner and it was replaced with a P218 and I have been running it a while but with a 54" mower deck it just wont pull the mower through thick grass as anything other than a snalis pace.

Yes the deck has new bearings, the gearbox is full of oil and the PTO shaft through the front axle has been greased. Everything is turning free.

So I am giving very strong consideration to purchasing either a Honda 22-24HP or the Robin Subaru EH722 engine. I am looking for thoughts advice opinions on either of the 2 choices or someone elses thoughts on the most likely candidate that will be the closest and easiest swap over.

I have pulleys and cluthches that will allow me to run either a 1&1/8 shaft or a 1&7/16 shaft.

I do know one person in Canada did the Robin Subaru change over and he wsays its doing him well and both the Honda and Robin has similar torque values. So now its real life experience running these engines and doing the repower that I am looking for advice on.

Many thanks

[massey driver]

I repowered my 1655 with a Honda 20 hp and its got no problem powering everything that I've used etc: on the tractor. Some of the things that I needed to do was with the flywheel drive was to make a adapter hub in order to use the oem splined shaft and pulleys that drive the pto shaft and the hydro shaft.I had a local machine shop do that for me just gave them the dimensions of the hub etc: that I had them make up.The other thing was I used the oem motor plate mount but had to raise the motor up 1 1/2 inches I just used some 1 1/2" sq tubing under the motor.Then of course I had to make a muffler to fit under the hood.The hood also has to have the baffle plate removed from between the motor and the gas tank.Other then wiring etc its not to bad to do.Oh yeah you'll have to make a seperate grd kill switch for the motor.The reason for this is that if you use the wiring switch etc that comes with the Honda motor as soon as you turn on the electric clutch the motor will die as it grds the coils killing the engine.If you need any advice etc just ask.Larry

[JDBrian]

Both of those are good choices but 2 other brands come to mind. Kawisaki and the Briggs Vanguard engines. The Vanguards are used by a lot of people for repowering the JD 140's and 300 series and seem to work well.I think Briggs partnered with a Japanese company to design them and they are rated for commercial duty.

[TUDOR]

Is the engine lacking power for the mower or the hydro? Thick grass will bog any engine running that large a mower and the hydro's demand for power should be minimal, unless working a hill.

Unless the Onan has high hours, I'd be checking the mower and the hydro very carefully. A fresh engine will not help if the problem is elsewhere.

[ErnRemy]

Subaru it the way to go! my god what i can do with 25hp there is only one hood mod the brace inside needs a half circle cut out to fit the air cleaner the Subaru also has an oil cooler that helps with heat under the hood ineed to vent the exhaust better but its all good

[Petenpole]

Is the engine lacking power for the mower or the hydro? Thick grass will bog any engine running that large a mower and the hydro's demand for power should be minimal, unless working a hill.

Unless the Onan has high hours, I'd be checking the mower and the hydro very carefully. A fresh engine will not help if the problem is elsewhere.

without the mower engaged the engine pulls the hydro with zero problems and runs just fine it even reaches max engine speed.
The mower deck is completely rebuilt all 6 bearings have been replaced, the shafts are in good condition and I even drilled the hubs and inserted grease fittings and have them full of grease.

The hydro does not seem to have an issue or be draining the engine. When mowing if I am going up any grade the engine just slows down and gets to the point it will barely pull the mower. Its almost as though the mower is to large for the engine. I do not know the hours on the engine but I do know it smokes under a load and it does leak oil. So its my humble opinion the engine is nearing of its useful life and i would rather not blow it up, saving it from its total demise for someone else.

Small engine warehouse in Indiana has a complete kit with a 24HP Honda for 1900.00 ( an that seems like a lot) Or I can buy locally a Robin Subaru 25HP for 1350.00 and build my own new hub for the flywheel and spacers to raise the engine.

I am leaning towards the Robin for cost reasons.

Any last thoughts from my knowlegable friends?

[HowardsMF155]

Interesting set of symptoms. I've got something similar going on with a MF12 that is somewhat new to me. I thought I'd conquered the problem yesterday after adjusting the governor for higher RPMS, as the mower cut well going down slope. But when I turned upslope, the motor didn't have the power to move the rig much faster than a slow amble without slowing way down. This same mower deck with a similar MF12 hydro that has a 13hp clone will zip through anything under similar conditions.

[olcowhand]

There is something up with your engine for sure. No way it should be so short of power. It should handle the deck easy in all but way overgrown grass.

[ducky]

Petenpole
Bring watching this one and when you stated that the engine slow with a load I strongly feel you have a governor issue. Make sure that the throttle shaft can go full open and that it does that also when a load is applied. It sure sounds like the carb throttle plate is not going full open.

[Petenpole]

Petenpole
Bring watching this one and when you stated that the engine slow with a load I strongly feel you have a governor issue. Make sure that the throttle shaft can go full open and that it does that also when a load is applied. It sure sounds like the carb throttle plate is not going full open.

Ducky thanks for the response, I adjusted the governor and the carb opens as smoothly as one could ever dream of. Prior to adjusting the linkage the engine wouldnt reach its full RPM's at a stand still. Now it revs up smoothly.

I think Daniel agrees with me the engine is getting weak and its time to find a donor or replacement.

[ducky]

"But when I turned upslope, the motor didn't have the power to move the rig much faster than a slow amble without slowing way down."

This is what put me on the carb not opening completely.
Do you get a little governor over shoot when you push the throttle wide open? Also when you turn the mower on can you see the throttle go wide open and then come back?

[HowardsMF155]

"But when I turned upslope, the motor didn't have the power to move the rig much faster than a slow amble without slowing way down."

This is what put me on the carb not opening completely.
Do you get a little governor over shoot when you push the throttle wide open? Also when you turn the mower on can you see the throttle go wide open and then come back?

I'll see if I can rig something to ensure the throttle is wide open next time I do this. Just got done cutting all the grass.

[ducky]

Let us know what you find.