Late Fathers PT-422: What should I do with it?

[3rd Coast]

Time to change the air filter?

Air filter is new, forgot to mention that.

 

[3rd Coast]

I'm wondering if a valve is sticking. Try a good dose of Sefoam and Marvel Mystery Oil.

My dad always thought it was a valve issue. What causes a valve to stick?

I see in the manuals it calls for a carbon cleaning on the heads at a certain hour range.

 

[oldnslo]

Most common cause of valves sticking is carbon buildup. Usually more of a problem on exhaust valves but it can be on either.

This problem gets worse if valve guide allows oil to work past into combustion chamber.

 

[MossRoad]

….

The good: It seems to run well most of the time. We've had a field day with it at home burying drain lines, moving trailers, and digging fence posts.

…

I really love this thing and am considering selling my larger Kioti tractor instead of selling this. Seems to be a better all around tool for my small homestead.

Edit: Machine has about 720 hours.

Keep the Kioti around for a while, get the PT running well, and do comparable jobs with them both. There are some things the tractor will do better when it comes to pulling tasks. But I’m glad you found the PT useful.

I kept my IH2500b for 10 years after we bought the PT. I never found a good reason to keep it for the tasks that we do once we got the little PT425. So, I sold the IH. The very few times I could use the IH, I just cut the task in half and do it with the little machine.

For us, lawn mowing is the main task, followed by snow removal, brush cutting, mulch and material moving, digging the occasional hole, and firewood harvesting. If I had to plow dirt or pull stumps, I’d probably get a conventional tractor. If I had to load dump trucks or move logs around for lumber, I’d probably get a larger PT model.

Anyhow, hope you get the thing running well and put it through more tasks.

 

[Tony H]

Sounds like a Lean running condition. Not sure how long it sat. I'd check fuel lines from tank to filter to carburetor. I'd also backblow gas line up to gas tank and see if the fuel tank is full of crud.

Carbon buildup can be cleaned up by DRIPPING water down the carburetor as the warmed up engine runs. CAUTION: too much water at one time can cause hydro lock.

 

[ponytug]

My dad always thought it was a valve issue. What causes a valve to stick?

I see in the manuals it calls for a carbon cleaning on the heads at a certain hour range.

Thanks for updating your saga.

One other item to check is the tappets, to make sure that they are straight.

Valve adjustment is straightforward, and worth doing if for no other reason than to eliminate it as a possible cause. While you are there, check the valve movement to see that they all "feel" the same. If you have sticky ones, seafoam in the oil and in the gas may help.

Several 425 owners have found crud (e.g. plastic shavings) in their fuel lines, so @Tony H's suggestion of blowing out the fuel line may be worthwhile.

I would have a look around for potential air/vacuum leaks as well.

Please keep us posted!

All the best,

Peter

 

[3rd Coast]

Today i changed the oil and filter. I also decided to drop new plugs in it since I had to head to the store for 10w-40 anyway. They didn't have the Robin factory spec NGK 6ES. The plugs I pulled out were NGK 4ES. Store didn't have either so I took a cross ref'd AC Delco plug.

The Robin was very hard to start and immediately backfired rapidly once I added any fuel. I pulled the plugs out and popped back the old 4ES. She started right up and ran fine. The 4ES looked fine if maybe a tad lean.

I'll pull fuel hoses next. Good ideas.

 

[Spanky100]

3rd Coast

Glad to hear you have your Father's PT at your home and are making progress with getting the engine issues sorted out. This very helpful group will help you get it running well over time. The worst case would be a engine change/upgrade.

Sounds like the PT-422 would fit your needs well. As you make the decision if you will keep or sell the PT my experience is the few things that I have from my Father and Grandfather bring additional joy to myself and children during use as we recall the memories of earlier generations using the same equipment. The PT-422 is a solid and simple to maintain effective tool that can last many generations if it is taken care of. Last year I gave my son the Cub Cadet Lawn Tractor that his Great Grandfather, Grandfather, and I used. He is the 4th generation using it now. His kids, when they get old enough to safely operate it, will be the 5th generation. Not many items can stand the test of time in our throw away economy. The PT sure can.

P.S. Keep the Kioti 2610 if you can. always nice to have additional equipment (toys).

 

[ponytug]

One more thought is that more ethanol has been added to fuel since your engine was originally designed, and your engine may run better on 89 octane. Easy to try.

(Don't forget the SeaFoam in the gas; I would be generous. If you also add SeaFoam to the oil, try to pick a time when you can run it for several hours and then change the oil.)

How To Add Sea Foam Motor Treatment To Crankcase Oil | Sea Foam

Sea Foam Motor Treatment can be used in every type of gasoline or diesel engine. When added to an engine’s oil crankcase, Sea Foam Motor Treatment works to

seafoamworks.com

All the best,

Peter

 

[Tony H]

Just a dumb issue I had on an older engine. Does this Robin engine have points and condenser? I had an engine drive me crazy run good one day, an hour later run crummy. Turned out the Condenser fit loosely in the condenser mount. It was getting an intermittent Ground.
How are the spark plug wires?
Is the flywheel rust free as well as the coil(s)?

 

[3rd Coast]

I'm wondering if a valve is sticking. Try a good dose of Sefoam and Marvel Mystery Oil.

Was able to try the Seafoam top end clean(the kind you spray in to the carb). Knock on wood, it ran flawless after using almost an entire bottle. I was able to run the rototiller and push blade for about an hour. Lots of starting, stopping, idling, high rpm. No hiccups. Feeling pretty good about that.

One slight newer issue, a lot of squeaking when turning. The greaseable pivot points have been greased. Maybe hydro seals around the pivot ram cylinders? Can those be lubed?

Edit: Another thing I noticed is the muffler heat output. Very hot on the right side(facing front) with a lot of volume coming out. Left side seems much lower air volume and much cooler. I dont know how the muffler is designed so that may be normal. Thoughts?

 

[airbiscuit]

I use ethanol free gas with a dose of Seafoan in all of my small engines. Prevents a lot of problems.

 

[MossRoad]

Was able to try the Seafoam top end clean(the kind you spray in to the carb). Knock on wood, it ran flawless after using almost an entire bottle. I was able to run the rototiller and push blade for about an hour. Lots of starting, stopping, idling, high rpm. No hiccups. Feeling pretty good about that.

One slight newer issue, a lot of squeaking when turning. The greaseable pivot points have been greased. Maybe hydro seals around the pivot ram cylinders? Can those be lubed?

Edit: Another thing I noticed is the muffler heat output. Very hot on the right side(facing front) with a lot of volume coming out. Left side seems much lower air volume and much cooler. I dont know how the muffler is designed so that may be normal. Thoughts?

On the squeaks… from past experience, it’s always been the ball joints at the ends of the steering rams. I doubted it. Terry at PT was pretty convincing. I sprayed them down good with super lube, let it soak in. Repeat. Threepeat. Squeaks gone.

 

[3rd Coast]

What does Power Trac put in the newer PT422 or PT425 machines? Do they support engine swaps?

On the squeaks… from past experience, it’s always been the ball joints at the ends of the steering rams. I doubted it. Terry at PT was pretty convincing. I sprayed them down good with super lube, let it soak in. Repeat. Threepeat. Squeaks gone.

This is exactly what I did, though I used white lithium grease as that's what I had on hand. I suppose I'll give her another go and let it work in a little bit.

 

[3rd Coast]

What does PT use to power new PT422s and 425s? Do they support repowering in older models? I'm no machinist or fabricator but I can assemble parts if there was a swap 'kit' I could purchase. Not in a hurry to do this since it seems to be running well but I'd like to understand the options.

 

[MossRoad]

What does PT use to power new PT422s and 425s? Do they support repowering in older models? I'm no machinist or fabricator but I can assemble parts if there was a swap 'kit' I could purchase. Not in a hurry to do this since it seems to be running well but I'd like to understand the options.

I do not know which engines they are using now. I recall some folks getting components from PT to re-power older machines, but cannot be certain.

You could always call PT at 1-800-THE-YARD and ask them.

 

[ponytug]

Congratulations on getting it running well and having fun with it!

What does Power Trac put in the newer PT422 or PT425 machines? Do they support engine swaps?

This is exactly what I did, though I used white lithium grease as that's what I had on hand. I suppose I'll give her another go and let it work in a little bit.

On the squeaks… from past experience, it’s always been the ball joints at the ends of the steering rams. I doubted it. Terry at PT was pretty convincing. I sprayed them down good with super lube, let it soak in. Repeat. Threepeat. Squeaks gone.

I think that "the squeaks" are really hard to localize, but for me they have always been the steering swivel eyes, specifically between the bolt and the tube.

Two things on "the squeaks"; Terry at Power-track recommends SuperLube synthetic spray as the lubricant of choice. Second, the steering cylinders have three concentric areas that need lubrication. There is a cylinder / swivel eye (the outer lubrication area) with a tube (the middle lubrication area, that needs lubrication inside and outside, I.e. both sides) held on by a bolt (the innermost lubrication area). It took me a few years to realize that I had to spray up against the underside of the frame ear holding the bolt to get over the top of the tube to lubricate the area between the tube and the bolt. Originally, I had just been lubricating the swivel/tube areas, which lead to "the squeaks".

All the best,

Peter

 

[ponytug]

Was able to try the Seafoam top end clean(the kind you spray in to the carb). Knock on wood, it ran flawless after using almost an entire bottle. I was able to run the rototiller and push blade for about an hour. Lots of starting, stopping, idling, high rpm. No hiccups. Feeling pretty good about that.

One slight newer issue, a lot of squeaking when turning. The greaseable pivot points have been greased. Maybe hydro seals around the pivot ram cylinders? Can those be lubed?

Edit: Another thing I noticed is the muffler heat output. Very hot on the right side(facing front) with a lot of volume coming out. Left side seems much lower air volume and much cooler. I dont know how the muffler is designed so that may be normal. Thoughts?

Here is a photo, near the tip of the green arrow at the top of inner tube and flange, you can see a slight gap. That is where you want some lubricant to get up and over.

All the best, Peter

 

[MossRoad]

Soak those puppies down!

 

[scotts562]

New machines have Kohler engines. Power trac sells the parts to swap a 25 hp Robin to a 25 hp Kohler, so they probably have kits for the 22 hp machines too. They are pretty easy to swap out. It is a night and day difference between the Robin and the Kohler. The 25 hp Robin is no longer made. Don't know about the 22 hp.

Here are the Kohler engine spec numbers I have used as a direct bolt on replacement for the 25 hp Robin: CH 730-3208 CH730-3207 and CH740-3363

Some other spec numbers that may work (call Kohler to confirm 866-465-6453) are CH730-3004 CH730-3331(key start on engine) AND CH750-3006

You will have to check with Power Trac and or Kohler to see if any of these are options for your PT 422