New PT-422 Stalls

[MCGN]

I am both a new PT-422 owner and new poster on this forum. Sorry in advance if I am asking a simple question, but I am struggling to find a solution to this problem. My PT has less than 30 hours and I have used it primarily for moving dirt/stone/etc. I began experiencing a problem 5-6 hours ago where the PT would lose all power and stall. I changed the following (oil, oil filter, plugs, fuel filter, air filter) and the PT ran great for a few hours then the same problem happened. I randomly get 30 minutes of work in (when it runs great) and then it quits. My belief is the engine is not getting fuel consistently, but I am at a loss to figure out what to do. I experience the same problem with the gas cap loosened.

I have talked to PT (they recommended changing the fuel filter and plugs) but beyond that, they said I should take the tractor to a Robins dealer. Unfortunately, I am not very experienced with this type of work, but was able to work through the simple changes above.

Any suggestions would be appreciated.

Thanks

 

[Marks481]

Clogged carburator jet? (easy to clean/replace)
Debris in the carburator float bowl?
Debris in the gas tank?
Water-logged carburator float?

What are you doing when it stalls? Is it when it first starts or after you have been using it for awhile? Some people have had problems with the fuel pump getting vapor-locked due to the close proximity of the fuel line and the fuel pump to the muffler causing the fuel in the line to boil. First way to fix it is tto replace the clear plastic fuel line with some quality solid blackj rubber line, and either shield or move the fuel pump.

Did you talk to Terry at PT or someone else? Jack Robin, where are you?

 

[MCGN]

Thank you for the suggestions. I spoke with Terry. He mentioned the possibility about this being a fuel shut off problem (I may not have the terminology correct), but that was when I got pointed to Robin Engines.

 

[woodlandfarms]

I second Vapor Lock.... If it runs fine on startup but falls apart after a half our or so...

 

[SnowRidge]

Welcome to the forum.

We like to know where everyone is located mainly because we are nosey , but also because location can sometimes help in diagnosing problems or suggestion solutions (altitiude, weather, etc.), so it's a good idea to fill out the location information in your profile.

You have already taken the first step I was going to suggest by running with the gas cap loose, so that eliminates fuel starvation due to a clogged tank vent.

Since you ran for some 25 hours without any trouble, was there anything obviously different about your operating conditions when the problem first showed up? Was it hotter, or did you move the machine to a higher altitude, etc?

Exactly how does it die? Does it miss, then stop? Will it run at all? Will it only idle, but not pull a load? All info helps.

 

[TheBigHeadKid]

Welcome,

Also check the 90 degree plastic fitting on the bottom of the gas tank. Several people including me had problems with glue (from the tank) breaking apart and getting stuck in the elbow, again restricting fuel.

 

[MCGN]

Thank you. I will try some of those suggestions today. There was no change in operating conditions when the problem first started - although I did have a very dirty air filter from moving dirt (60 yards).

The problem is not load related. It can happen randomly, but also it may work for a while perfectly. Once the problem starts and the engine stalls (not instant shut off - rather like it is choked for gas), it will start again (sometime right away), but then typically stalls immediately.

When this happens, I try to move around the fuel line and filter (without buring my arm) and this helps sometimes.

 

[SnowRidge]

Not having a Robin myself, I can only offer general suggestions. I understand that they are susceptible to vapor lock. I wonder if you have some crud trapped under the engine shroud that is causing it to run slightly hotter than when brand new, thus triggering the vapor lock issue.

You might try blowing the cooling air passages out with compressed air, and see if that helps. Some of us do that after every use.

 

[SpringHollow]

Unfortunately, some people have had crud left over from manufacturing still in their gas tank which ended up restricting fuel flow in a manner similar to what you are seeing. You might want to drain the tank and inspect it.

Ken

 

[MossRoad]

Unfortunately, some people have had crud left over from manufacturing still in their gas tank which ended up restricting fuel flow in a manner similar to what you are seeing. You might want to drain the tank and inspect it.

Ken

I'd agree with you. There have been numerous reports of crud in the fuel tank that settles in where the fuel leaves the tank.

The first thing I'd do, and it costs less than five bucks, is get a clear fuel filter from an auto parts store and put it into the fuel line near the gas tank. That way you can see if fuel is even getting to the filter from the tank. You can also check it at each refueling to visually see if crud is getting into it from the tank. Also, get a large funnel with a screen in the neck and use this when you refuel. It is amazing how many times I have found a blade of grass or speck of leaf in the funnel after fueling.

 

[Phils]

I'm with the others: check the elbow coming out of the fuel tank for debris. Mine had it. I couldn't see it by looking in, I had to unscrew the elbow to see it, and then it was easy to clean it out. It was milky colored glue residue, I guess, but invisible when submersed in gas.

You can remove that fitting if you have 1/3 tank of gas or less. Just unbolt then tilt the tank until the fuel level is below the fitting and gas cap.

The clear filter can help.

Also, when it quits look into the fuel tank and see if bubbles are coming up out of the fitting, a sure and quick check for the vaporlock problem.

I suspect that I may have had more of a vaporlock problem than most. Our gas in CA is worse and lower octane than the rest of the country. The temps in my area are warmer than most. I've tried more fixes than many. My PT no longer shuts down from vaporlock but the gas in the lines will turn to vapor a few minutes after turning the machine off after a period of hard work. I use an electric fuel pump now and can hear the difference when it's pumping vapor or liquid, but it'll still restart and run fine.

IMHO these are hot-running machines with a poorly designed exhaust system and a thin fuel hose running next to it.

And I love it anyway... I hope you get as much satisfaction from yours as most of the rest of us.

Phil

 

[MCGN]

Thank you everyone for the suggestions. I went ahead and drained the fuel tank, removed it an cleaned out the elbow. There was something inside which may have been causing the problem. I also changed the hose to the black fuel hose and put in the new fuel filters.

I have used it for a couple hours today (not continuously - the day job gets in the way) and have not experienced any problems - so hopefully this will do the trick. I have another 20 yards of mulch and 10 yards of topsoil to move on Saturday so that will be a good test.

Other than this problem (and my first experience changing the oil) the machine has been great.

 

[BobRip]

Thank you everyone for the suggestions. I went ahead and drained the fuel tank, removed it an cleaned out the elbow. There was something inside which may have been causing the problem. I also changed the hose to the black fuel hose and put in the new fuel filters.

I have used it for a couple hours today (not continuously - the day job gets in the way) and have not experienced any problems - so hopefully this will do the trick. I have another 20 yards of mulch and 10 yards of topsoil to move on Saturday so that will be a good test.

Other than this problem (and my first experience changing the oil) the machine has been great.

Sounds like you found the problem. If it happens again try adding some choke. If that helps then it is definately a fuel problem I also had trash in the elbow from the tank top sealant.

 

[TheBigHeadKid]

If so many of us have had crap in the elbow, has anyone told Terry or crew about the glue problem. Mine looked like the cement (glue) used to hold the female coupling/fitting to the bottom of the tank starts to break down with the gasoline and starts to chip away and those pieces get caught in the elbow instead of being caught in the filter. I really have though about a standpipe filter inside the tank instead of the elbow...

- I looked back this morning and there was a previous discussion with pictures of what looks like chips of glue/cement.

* I hope that was your problem.
DWG

 

[Clarke]

It wouldn't help to tell Terry. Actually we only think these tractors are made in Tazewell. They are really imported from China.

sg

 

[J_J]

It wouldn't help to tell Terry. Actually we only think these tractors are made in Tazewell. They are really imported from China.

sg

How in the heck did you come up with that bit of knowledge, or is that just BS.

 

[J_J]

It wouldn't help to tell Terry. Actually we only think these tractors are made in Tazewell. They are really imported from China.

sg

How in the heck did you come up with that bit of knowledge, or is that just BS.

 

[Clarke]

It's BS but maybe I insulted the chinese there tractors may have a little better workmanship and are more reliable. (Just kidding.)

sg

 

[Marks481]

You taken a look at the heavy machinery that comes out of China? Try swinging by Harbor Freight, and taking a look at one of their RF-31 mill clones before you starting saying things like that. The good imported stuff like Grizzly, WMH/Powermatic, General is good because the customer supplied QA representative rejects the bad stuff before shipment (and I have heard that the rejected stuff is then spray painted red...).

Wait until you drain the oil out of a mill's gear case, and find it is 25% sand from the iron casting process that was never cleaned up prior to assembly. Then you grind off the nice paint job and find a significant portion of the heavy iron casting is actually bondo filling in all of the casting defects.

Are you sure that you aren't confusing quality in a tractor for stream-lined stamped steel (or plastic) cowlings that look nice? I haven't looked closely at the tractors, but I know what the heavy machinery looks like.

 

[horse7]

I'm sure PT has a never ending stream of Chinese companies lining up at their door trying to convince them to sub out to China and just stick the PT label on.

The typical problem is though, once the Chinese get in the door they don't need you anymore (the Indians sub out subsections that are too small for the Chinese to take over whatever is being produced. The Americans tend to learn this the hard way, or maybe not at all).