PT 425 Robin Engine Problem

[mlhunter]

I can see how having pumps on both ends of the engine would make it more difficult! If I had not have had a quick lunch in between and a quick trip to the hardware store for some 1/4 inch chain for an engine hoist connection I would have finished in approximately 3 hours (and I worked very slowly)!

I was very surprised at the type of coupler they used and how simple it is to mate the engine's shaft up to the hyrdaulics. Kudos to Power Trac for their PT425 Robin/Subaru engine to hydraulics configuration!

However....

Removing that coupler from the engine's front bearing cover was difficult. The coupler's housing unbolted easily. However, the only way only way I found to get the keyed sleeve removed from the engine's shaft was to force a tapered chisel between the keyed coupler sleeve end and the engine's front bearing cover. I didn't have to use a 4# hammer but I did have to get pretty "business like" with a medium size ball peen hammer. I alternated hammer blows 180 degrees to avoid any potential cocking issues. The only other way I could see how this could be done would be with a massive screw type puller and that would be a highly specialized (and expensive if purchased) tool. It didn't appear that anything was damaged by that process and hopefully that is the case.

The only potential re-assembly issues I can see are:
1) Aligning the crankshaft with the cover if it changed position during or after the cover removal;
2) Re-installing the coupler shaft sleeve to the engine shaft at the correct depth; and
3) Re-positioning the engine inside the tractor's engine well to get the mounting bolts up through it and the nuts back on to the bolts. This is one thing I think Power Trac could configure differently to make this easier to do.

I'm trying to decide what kind of bolt guides I might make and/or use on the 3rd issue. If you had the same issue how did you get the first two lined up?

Terry of Power Trac had never heard of a governor problem with this engine so my issue is probably a freak thing! I also noted that the Robin/Subaru engine's crankshaft and bearings are massive for this size of engine! I can see why this engine should last 3000 hours or more!

 

[SnowRidge]

Hmmm. My couplers were locked to the shafts with set screws. Once I loosened them, it wasn't difficult to get them off the shafts. Getting the stuck together couplers apart took some effort, as I recall.

Nothing coupler related was fastened to the engine housing on the Kohler, so I can't offer any suggestions there.

On my machine, I unbolted the engine mount and took the engine out with the mount still on it. I could never have unbolted the engine from the mount and bolted it back in with the mount still in the tub. I believe I mentioned that in the write up. Was your mount bolted or welded in?

There are a lot of things Terry has never heard of before. Most of them seem to happen to people on this forum.

 

[mlhunter]

Hmmm. My couplers were locked to the shafts with set screws. Once I loosened them, it wasn't difficult to get them off the shafts. Getting the stuck together couplers apart took some effort, as I recall.

Nothing coupler related was fastened to the engine housing on the Kohler, so I can't offer any suggestions there.

On my machine, I unbolted the engine mount and took the engine out with the mount still on it. I could never have unbolted the engine from the mount and bolted it back in with the mount still in the tub. I believe I mentioned that in the write up. Was your mount bolted or welded in?

There are a lot of things Terry has never heard of before. Most of them seem to happen to people on this forum.

When I went to install the coupler back onto the main bearing housing I found the key locking setscrew in the coupler. Apparently it was underneath and when I felt around under there I didn't feel anything and I did that twice! In retrospect I should have looked under it with a mirror! I didn't hurt anything by forcing it off but it sure made the job a lot harder than it needed to be!

There is no engine mount component per se. The engine is mounted directly to a rectangular plate welded to the bottom of the chassis. A long bolt (4 of these) is inserted from the bottom of the tractor through the chassis and plate, through a 2 3/4" long 1" metal tube, then through a hole in the base of the engine block.

Its a tricky thing to get everything lined up and the engine set in the right place for bolt insertion. Since I installed the engine three times (long story) I found a decent workable method was to put a board somewhat larger than the plate inside under the chassis and balance that on top of a jack. By moving the board around I inserted the bolts one by one through the chassis, then jacked it up until the bolts were upright and solid. Then it was a simpler process to get it lined up, slip it onto the bolts, and get the nuts started. I think this is something that Power Trac could easily improve on if they haven't already!

I used a come-a-long for engine lift. A chain hoist would also have made it a bit simpler.

I'm thinking of documenting the engine removal steps for my own use down the road if I need to do this again. I could post it if you think it would be helpful for those that have Robin/Subaru equipped tractors.

 

[Marks481]

Since I installed the engine three times...I'm thinking of documenting the engine removal steps for my own use down the road

Now that you have had so much practice and have streamlined the process, how about you pull it out and install it a fourth time while viedotaping.....

 

[SnowRidge]

Now that you have had so much practice and have streamlined the process, how about you pull it out and install it a fourth time while viedotaping.....

Heh, heh.

 

[Central_PA_Chris]

Terry of Power Trac had never heard of a governor problem with this engine so my issue is probably a freak thing!

I'll call baloney on that, my 2007 PT 425 with Subaru/Robin 25hp blew the rear main seal out at 2? or maybe it was 4? hours on the clock when the governor kicked the can and I know he heard about that one. I was lucky, no fire when the oil sprayed all over the engine compartment.

 

[Phils]

I'll call baloney

That was polite, Chris.

Baloney isn't the term I've always used.

Phil

 

[MossRoad]

Bologna.

 

[Marks481]

That was polite, Chris.

Baloney isn't the term I've always used.

Phil

But this is a family friendly site, so we will have to leave it there...

 

[mlhunter]

Now that you have had so much practice and have streamlined the process, how about you pull it out and install it a fourth time while viedotaping.....

Probably NOT! However, I do plan on documenting the process for future use. I hope to get that done this coming week.

The tractor is now running right except its doing a bit of rpm "hunting" at mid-low rpms. My brother who used to work on MO state road equipment said that is not abnormal with a new governor.