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.