PT422 Engine shaking / sputtering

[MossRoad]

The Kohler in my PT425 model year 2001 starts reliably at ZERO degrees provided I have a good battery and spark plugs. I also give it one shot of ether below 20 degrees before attempting to start. Above 20 degrees, I just hop on it and crank. My original battery lasted 6 years! I need a new starter solenoid right now, after 9 years and 400 hours.

The PTs have the added burden of spinning both the engine and hydraulic pumps when starting, no matter which engine they have. I do nothing special to start mine, like warming the engine, battery or hydraulic tank. Only below 20 do I give it the shot of ether. I think ours failed to start one time since 2001. I'd have to go back and search my posts over the years.

I was kind of sickened to recommend the Power Trac PT425 to so many people and then have so many people report cold starting problems when PT switched away from the Kohler engine. I wish they would go back to the Kohler. Apparently cold weather is not a problem in VA.

I like the idea of a fuel injected engine VS carb, but have no idea how they work in the cold on small engines like ours. I know my 93 Chevy Suburban has throttle body fuel injection and starts at all temps. So did my 93 Chevy van at -22. Virtually every car in the last 15 years has fuel injection and they all start. It would be nice if the small engines worked the same.

Be sure to put some stabil in the gas cans as soon as you fill them at the station.
Put some heat fuel treatment in there, too, in the winter.
Keep the battery charged.
Remove and clean your battery connections before winter.
Check your plugs before winter starts.
Fully choke the engine, start cranking, then increase the throttle until it goes BANG! :thumbsup:

 

[BobRip]

Moss, I keep my PT422 with Robin engine in an R50 insulated attached garage which rarely gets below 60. When I kept it outside in the tool shed it would not start at 40. I would say that the Kohler is better.

 

[KMA]

Moss, I keep my PT422 with Robin engine in an R50 insulated attached garage which rarely gets below 60. When I kept it outside in the tool shed it would not start at 40. I would say that the Kohler is better.

Yeah, I agree with this too.

Unfortunately it appears that the EH72 FI model only comes with a 1 1/8" keyed shaft, vs 1 7/16". I was getting my hopes up that the fuel injection version would somehow alleviate some of my issues with the Robin engines, and still allow it to be a drop-in replacement. Now I'm sort of back to square one.

I wish I had the shaft length for the PT's Robin engine. I can get all other dimensions off of the web, and having the length would allow me to narrow down my search for a replacement. I can measure it up once I pull it out of the tractor, but that might be several weeks. I'm putting up molding and redoing the dining room this weekend, and then I'll be in Europe the following week. Work and kids sports fill up the time in between.

I'll keep digging...

 

[Gravy]

Thanks guys. I'll have to give the EH72 FI some more thought. I guess I could adjust the stop on the throttle cable connection so that it only revs up to a point. Anyone find a place that sells them online? I can't seem to find the fuel injected model.

Regarding cold starts, I agree that the biggest problem is turning the pumps with all that cold hydraulic oil, but I couldn't even get the engine to start when it was 50-55 degrees out. I would have to put a heater on the hydraulic oil tank AND make sure the battery was fully charged to even stand a chance.

Thanks again for everyone's input. :thumbsup: I'll keep you posted.

Rather than the throttle stop, there will be a governor adjustment that will let you limit the maximum RPM's while maintaining full power up to that point.

According to Robin, one of the advantages of the FI is quicker starting in cold weather. I'll believe it when I see it.

I personally think that the cold starting problem is because the starter doesn't spin the engine fast enough for the magneto to make a strong spark. I've been tempted to figure out how to adapt a crank-trigger electronic ignition from a car or motorcycle.

 

[KMA]

Rather than the throttle stop, there will be a governor adjustment that will let you limit the maximum RPM's while maintaining full power up to that point.

According to Robin, one of the advantages of the FI is quicker starting in cold weather. I'll believe it when I see it.

I personally think that the cold starting problem is because the starter doesn't spin the engine fast enough for the magneto to make a strong spark. I've been tempted to figure out how to adapt a crank-trigger electronic ignition from a car or motorcycle.

Good info, thanks!

What do you guys think about Kohler Command Pro engines? Years ago they used to be the "ones to get" in commercial lawn mowing equipment... I but I know Kawasaki has made a big push since then and are well respected. I love the Hondas, and I hear some of the B&S engines are good depending on the product line.

I think there might be a Kohler Command Pro that could fit (which has auto compression release and electronic ignition to help with cold starts?):

http://www.kohlerengines.com/onlinecatalog/productDetail.htm?productNumber=Command PRO CH730

Okay... I think I found the Robin shaft dimensions: 1-7/16" x 4.37" keyed

I think I might be able to get the Kohler Command to fit... need to check some other dimensions first. The shaft length is only 0.07" longer. Length of the engine is only 1" longer and I might have just enough room. Width is narrower, so no problem there. I should be good on height too. Shaft height a bit different, but I should be able to account for it. Need to determine how the pump housing will mate and if the bolt holes line up.

 

[KentT]

Rather than the throttle stop, there will be a governor adjustment that will let you limit the maximum RPM's while maintaining full power up to that point.

According to Robin, one of the advantages of the FI is quicker starting in cold weather. I'll believe it when I see it.

I personally think that the cold starting problem is because the starter doesn't spin the engine fast enough for the magneto to make a strong spark. I've been tempted to figure out how to adapt a crank-trigger electronic ignition from a car or motorcycle.

Gravy,

I agree with how sluggish the starter is pumping all that cold hydraulic oil...

Here's a description of converting an old magneto ignition with points/condensor to a coil ignition. Don't know if it's of any value or not:

Magneto to Coil

 

[KMA]

I feel obliged to make a quick comment about a particular website I've been interfacing with regarding my potential engine purchase... I found the EH72 for a good price, no tax and free shipping here: 720cc Subaru Horizontal Engine EH720DS0032

I've been sending emails to them all day today, and they been getting back to me ultra fast and with terrific feedback. If there is anyway for me to purchase the engine through them, I'm definitely gonna try to make it happen. Matter of fact, I think the person I've been exchanging emails with (Peter Liesch) is one of the owners. He's been polite, responsive and very helpful.

 

[Marks481]

Okay... I think I found the Robin shaft dimensions: 1-7/16" x 4.37" keyed

I think I might be able to get the Kohler Command to fit... need to check some other dimensions first.

I believe that the engine is connected to the pump with a Lovejoy (spider) coupling. Which are available in an infinite number of sizes and are designed to join dissimilar shaft diameters and styles. So it might not be a big issue. You should be able to buy a new coupling to join whatever engine you buy to the pump.

They couplings on the PT should look exactly like these:
http://www.mcmaster.com/#spider-couplings/=9go96f

Here is a picture of what the couplings on Bobrip's engine looked like.
http://www.tractorbynet.com/forums/...e-main-bearing-power-trac-bearing-seal-gasket

 

[Gravy]

Gravy,

I agree with how sluggish the starter is pumping all that cold hydraulic oil...

Here's a description of converting an old magneto ignition with points/condensor to a coil ignition. Don't know if it's of any value or not:

Magneto to Coil

Kent,

That's a nice conversion. I'm not sure if it will work with a non-point magneto. I also have no idea how I might work out the timing on the v-twin. Maybe someday.

 

[BobRip]

I personally think that the cold starting problem is because the starter doesn't spin the engine fast enough for the magneto to make a strong spark. I've been tempted to figure out how to adapt a crank-trigger electronic ignition from a car or motorcycle.

I got an upgrade kit for this cold start problem from Robin. It included new more powerful coils and a more powerful starter. I think you hit the nail on the head and would say that Robin agrees with you. I can't say that I see a difference. Of course I have gone to a 15w50 Mobil1 in the transmission, which is a lot thicker that the 5w30 they originally had. This has improved wheel motor torque significantly especially when the fluid is hot. I cannot say that I have experimented with the cold starting. After my one experience in the cold shed, I have always stored it in the heated garage.

 

[Gravy]

I got an upgrade kit for this cold start problem from Robin. It included new more powerful coils and a more powerful starter. I think you hit the nail on the head and would say that Robin agrees with you. I can't say that I see a difference. Of course I have gone to a 15w50 Mobil1 in the transmission, which is a lot thicker that the 5w30 they originally had. This has improved wheel motor torque significantly especially when the fluid is hot. I cannot say that I have experimented with the cold starting. After my one experience in the cold shed, I have always stored it in the heated garage.

I got the starter upgrade for free back when JackRobin was here. He said I already had the upgraded coils.

I changed over to Castrol Syntec 5W50 a few years ago when it was on sale really cheap.

Still, if it's under 50*F I have a magnetic block heater on the hydraulic tank and another on the tram pump. I also have a Battery Tender connected. If it's below 45* I wrap everything in tarps and moving blankets. If it's below freezing I may or may not have to do all of the above and supplement by jumping from a running vehicle and adding starting fluid as needed.

Once it gets below 50, it's random chance. It might start right up, or I might have to bring in the big guns. I've always gotten it started, but it gets ugly sometimes.

Sometimes the magic works, sometimes it doesn't.

 

[BobRip]

I got the starter upgrade for free back when JackRobin was here. He said I already had the upgraded coils.

Sometimes the magic works, sometimes it doesn't.

I got my coils and start free, so kudos to Robin for that.

I really don't like to pull out the magic. Thanks to my builder for the super insulated garage of Poly Steel ICF forms.

 

[Gravy]

I got my coils and start free, so kudos to Robin for that.

I really don't like to pull out the magic. Thanks to my builder for the super insulated garage of Poly Steel ICF forms.

Oooh! I want an ICF shop!

Poor Kermie sits under an open sided lean-to shed here in SW Virginia. He endures cats and cold and stink bugs... and he still plows that snow and mows that grass and digs rocks & dirt and moves stuff around.

It's not easy being green...

 

[Gravy]

I believe that the engine is connected to the pump with a Lovejoy (spider) coupling. Which are available in an infinite number of sizes and are designed to join dissimilar shaft diameters and styles. So it might not be a big issue. You should be able to buy a new coupling to join whatever engine you buy to the pump.

They couplings on the PT should look exactly like these:
McMaster-Carr

Here is a picture of what the couplings on Bobrip's engine looked like.
http://www.tractorbynet.com/forums/...e-main-bearing-power-trac-bearing-seal-gasket

I'll second that. Shaft length and diameter are easy fixes. If it's too long, chop it off. Ignore balance questions - it's a small diameter and it turns pretty slow. You could torch it at a 45* angle and it would be OK. A little shorter, fatter or skinnier can all be accommodated by the couplings. The big question is: "Will the engine fit in the tub?"

 

[duane]

I thought I remember a thread back quite a while where someone replacing their engine indicated that Power Trac cut the length of the crankshaft to fit. So you may end up cutting the length anyways.

 

[MossRoad]

I feel obliged to make a quick comment about a particular website I've been interfacing with regarding my potential engine purchase... I found the EH72 for a good price, no tax and free shipping here: 720cc Subaru Horizontal Engine EH720DS0032

I've been sending emails to them all day today, and they been getting back to me ultra fast and with terrific feedback. If there is anyway for me to purchase the engine through them, I'm definitely gonna try to make it happen. Matter of fact, I think the person I've been exchanging emails with (Peter Liesch) is one of the owners. He's been polite, responsive and very helpful.

Good customer service is hard to find! Glad you found someone that gives a darn. :thumbsup:

 

[MossRoad]

I found a post from January 16, 2009 that I made when my Kohler failed to start at -19 degrees. Turned out I flooded the engine and got it started at -7 degrees the next day.
=======================================================

Re: Cold Weather Starting Well, it turns out it was just flooded!

I noticed fuel spitting up out of the carb and exhaust. So, I shut off the fuel completely and opened the choke fully and cranked it for 10 seconds and then waited a minute, repeating until it stopped spitting fuel out of the exhaust and carb. Then I set the choke to full with throttle off and cranked it. While cranking, I slowly increased the throttle and it fired right up without any starting fluid. The temp was -7F.

So, I need to revise my cold weather starting procedure to full choke, NO fuel, and increase the fuel slowly as I crank until it starts. I may also change the plugs, as they are the originals from 2001 with 350 hrs on them.

=======================================================

Here's a link to a whole thread that year we did on cold weather starting.

Don't want to get off topic about the original topic.

http://www.tractorbynet.com/forums/power-trac/134987-cold-weather-starting.html

 

[Marks481]

I think the person I've been exchanging emails with (Peter Liesch) is one of the owners. He's been polite, responsive and very helpful.

Did you ask them about the availability of the FI version?

Again, the 1-1/8" shaft size is not a big deal. You can buy the coupler for the engine from mcmaster-carr; these couplers are bored out in 1/16" increments.

It is likely that the PT coupler is a different brand, so you would need to buy both engine and pump coupler and the spider. The 25hp engine puts out a peak torque of 38 ft-lbs (456 in-lbs) at 2900 rpm, which means the smallest coupler you should use is size "F" with a hytrel or urethane spider. Assuming the hydraulic pump has a shaft smaller then 1-3/8", that means the coupler will run you $18 + $18 + $22 = $54.

McMaster-Carr

 

[KMA]

Did you ask them about the availability of the FI version?

Again, the 1-1/8" shaft size is not a big deal. You can buy the coupler for the engine from mcmaster-carr; these couplers are bored out in 1/16" increments.

It is likely that the PT coupler is a different brand, so you would need to buy both engine and pump coupler and the spider. The 25hp engine puts out a peak torque of 38 ft-lbs (456 in-lbs) at 2900 rpm, which means the smallest coupler you should use is size "F" with a hytrel or urethane spider. Assuming the hydraulic pump has a shaft smaller then 1-3/8", that means the coupler will run you $18 + $18 + $22 = $54.

McMaster-Carr

Yes, here is his response:

"Our price on the EH72 fuel injected model is $1789.97 which includes free shipping."

So it's about $300 more or so.

You seem to have a pretty good handle on the types of couplers, etc. Maybe when I get the engine out I could post of pics and we can decide how to make this work with a different shaft size/type.

That being said, the 25hp Kohler Command Pro I've been looking at isn't fuel injected, but it seems to have some pretty decent features that might help it with cold weather starting. It also will probably fit and the shaft size is a very close match (although it sounds like I might need to cut it anyway). To be honest, a liquid cooled engine isn't completely out of the running yet, although I'm not sure it is really worth the extra cost and effort. I think I'm mostly interested in them due to the "coolness" factor (no pun intended) and maybe the challenge.

The other nice thing about Kohler is that it has a whole catalog of neat options and accessories available. I couldn't find the same thing for the Robins. For example, there is a remote oil filter attachment that lets you place the filter in a more convenient location. There is also a nice selection of muffler and crossover manifolds that would same me a lot of exhaust modification work. Maybe there are similar items for other engines, but I couldn't find them as easily, and I doubt they are as extensive as the Kohler catalog.

Thanks again for everyone's input.

 

[KMA]

Oh yeah... and I will definitely take pics and create a how-to thread/tutorial on the engine swap. I think there are many people on this forum who could handle a project like this, but don't want to take on the risk due to some unknowns. If it can be broken down while addressing the main concerns, it might empower others to dive in and upgrade/replace their PT engines. If/when I'm successful, I'd be happy to share my experience.

Here's another opinion question: Disregarding potential issues with fitment and/or cost, which would you prefer in your PT?

1. a liquid cooled, carbureted Kawasaki
2. an air cooled, fuel injected Robin
3. an air cooled, carbureted Kohler Command Pro