Prairie Bobcat 6x6 amphibious machine

[bc_archer]

Hi everyone, I have a Prairie Bobcat (PB) 6x6 amphibious machine with skid steer type steering which I purchased a few years ago that I'm trying to get running again. After replacing the starter on the 17hp Kohler twin cylinder engine it ran well, but I had a problem with one of the drive chains being too loose, which I attempted to tighten without much success at first, but figured it out later.
Another issue is that when accelerating to go up a hill or up loading ramps the governor seems to disengage, and I lose power and I can't make it up the ramp or steep hill. It doesn't seem to be a problem when I get a run at it, but if I try to ease up the loading ramps it starts going up and then about half way up the ramps I lose acceleration and the throw-out pulley (like the drive belt pulley on a snowmobile) or whatever it is called widens up and the belt becomes disengaged and the machine looses forward movement. Any information on how to adjust the governor or whatever it is that needs adjusting will be a great help and much appreciated.
I also have a question about the steering brake bands; the brake bands on the PB are narrow bands that compress around the outer circumference of the drum or rotor instead of compressing the rotor between two pads like found on cars or motorcycles. Is it possible to change this braking/steering system to something like a motorcycle braking system or should I just stick with the existing system, which doesn’t seem like it would work as well and would be harder if not impossible to find parts for? Should I consider operating the braking system with hydraulics instead of using existing linkage system?
I have a few other questions but will try to address them one or two at a time in future posts.
Thanks

[dirtdobber]

Welcome bc archer. If I understand, your machine will run fine on flat ground but going uphill you lose engine speed. This doesn't make sense, so I want to pose a question. Do you think that when going uphill, and trying to go slow like you would with loading ramps, you are teetering right around the engine rpm that allows the drive clutch to engage/disengage? Or, does you engine actually drop to idle in these situations?

As far as your transmission question, it sounds like you have a T20. Don't change it as the T20 is rugged and, although some parts can be hard to find, many parts are available. Hopefully your is in good shape.

[bc_archer]

yes i believe that is the case, just as i get enough rpm to go up the ramp it starts moving forward then all of a sudden the clutch widens and the belt slips because the pulley gets too wide for it to grab. i was thinking it might have something to do with the governor, but i don't know much about them so don't know if my suspicions are correct or it's something else.

[bc_archer]

BTW the markings on my transmission reads T92-1B so would you say that it is a T92 transmission or is that just how the T20 transmission is marked?
Thanks

[bc_archer]

one other question, it is currently not running because i haven't hooked up the ignition wires after removing the cab to get at the drive chain tightening adjuster and it is currently in gear and i can't get it into neutral even with all wheels off the ground. Does this transmission require the engine to be running to engage the transmission into neutral or should i still be able to shift it without it running?

[dirtdobber]

Post a pic so we can see what you have.

[bc_archer]

wii do

[bc_archer]

Photos of my Prairie Bobcat 6x6

See attached photos including transmission and drive pulley linkage. Brake linkage pics to follow

[bc_archer]

Photos of my Prairie Bobcat 6x6

photos of the left and right side brake linkages, clutch(?) assembly and overhead views of drive system

[john swenson]

archer...that's a cool machine . was interesting the dash diagrams of the clutches and tranny readings. looking forward to watching your project unfold . johnboy va.

[bc_archer]

It also has a cab complete with windshield wipers and in cab heating and defrost using hot air from the engine compartment, but I had to take it off to get a better look at the drive chain adjusters and will put it back on for winter once iI'm done.

[dirtdobber]

Wow. There's a lot going on with that drive train. I think it's pretty cool that it has 4 speeds in addition to the range of speeds offered by the CVT.

[john swenson]

i did just watch the short video of a bobcat ( mc dougal auctioneers ) on u tube . shows some good shots of the shifter and such . looks just like yours ! cab and all . johnboy va. p.s. could it be the same one ? who knows...

[bc_archer]

BTW I researched the T92-1B transmission and found it was used in some tractor models and parts are still being made by Olympic Gear Products. I also found out the shifting lever wears out after about 20 years of usage resulting in it being stuck into two gears at once, but it can be repaired by building up the rounded edges with hard welding and then ground back to squared edges, so I'm going to take it apart and take it to a buddy who's a fabricator to get fixed if that is the problem. Thank goodness for everyone that posts information online to help other people out, I can't imagine trying to find this same information out 30 years ago. I will post updates as I proceed with the restoration.

[bc_archer]

I bought mine near Hinton, Alberta a few years ago, so doubt that it would be the same machine as the one you saw. Now that I'm retired I have time to work on it and can't wait to get it running again.