What to look for when testing a used machine

[MossRoad]

Heck, see what the mechanic has to say about the engine before considering replacing it. It may be something simple like bad timing. Have the compression checked first. If it has good compression you can then figure if its a fuel issue or an electrical issue. Those issues are easily resolved and usually not that expensive. If the compression is bad, make sure the valves are set correctly. If it still has bad compression, ask your mechanic how much surgery can cost VS a replacement engine.

 

[woodlandfarms]

Throttle cables go out on the PT's. Mine got gummed up over the years.

 

[Frank Sorbello]

I just took my 422 to a very good small engine mechanic. We could not get it started. He is going to dive into further. I am hoping he can find the problem.

 

[Frank Sorbello]

I stopped by the mechanics today. They can not get it started. Said they believe when the engine was rebuilt the fly wheel was tighten all the way and now she is out of time. Said they would have to pull the engine. They said it is backfiring through the carb and the exhaust. I called Terry at Power Trac and told him their findings, he didn't necessarily agree it was out of time.
any thoughts?

 

[Gravy]

My 2004 PT 425 has the Robin 25hp engine. It will backfire through the carb, flood and refuse to start if it's not cranking fast enough. It gets worse when the valves need to be adjusted, which happens more often than the maintenance schedule indicates. Cold weather makes it worse. Even with magnetic block heaters on the hydraulic tank and the tram pump, there have been times when the only way to get it started was to jump it with a running vehicle & heavy-duty jumper cables, plus starting fluid. I think the magneto just doesn't put out a strong enough spark if it cranks a little slowly.

The battery, cables and starter were all marginal at best when new. I got an upgraded starter while it was under warranty, and have recently upgraded to a considerably larger battery and heavier cables. That has helped considerably.

 

[Frank Sorbello]

Do you think the Robin Subaru 22hp or 25hp is the best engine that Power Trac can put in there machines? What good is the tractor if it won't start when you need it.

 

[Marks481]

Do you think the Robin Subaru 22hp or 25hp is the best engine that Power Trac can put in there machines?

I think Robin has made improvements in the last few years which have helped resolve many of the starting problems.

If my Robin 22 HP engine died, I would replace it with a Robin... the 27HP Fuel Injected variant.

 

[J_J]

Has anyone set the valves correctly ????

 

[Marks481]

...now she is out of time. Said they would have to pull the engine.

Pulling the engine is a bit drastic. I am with Terry on this one. Mechanic wants to pull the engine because he wants to see Top Dead Center on the flywheel to adjust the valves. Absolutely not required.

Pull the valve covers. Pull the spark plugs. Soda straw in the cylinder through the spark plug hole, rotate the crankshaft by lightly goosing the starter switch until you see the cylinder at the top. Adjust the appropriate valve clearance (either intake or exhaust, whichever one is open). Repeat 3 more times. You don't need access to the flywheel, as valve adjustment is done at TDC. Timing adjustment should take 15 minutes.

My PT422, when very cold, flooded out/backfired, refused to start. I was desperate, as was moving (to a new house) and had some heavy loads to shift in 20F weather. Pulled the plug, setup two space heaters and a few hours solved the problem.

Cold hydraulic fluid=slow cranking=insufficient spark (as was stated above) leads to flooding out the engine, which makes it worse. Pull the plugs, let it sit overnight in the garage was a space heater blowing underneath/into the engine compartment, warm up the spark plugs with a propane torch, then try again.

 

[Frank Sorbello]

Mechanic called today. He got it running. Adjusted the valves. They were loose. Said the bendix was stuck in the starter. Noticed one cylinder wasn't firing. Found a bad wire, that cuts off the engine has a short. Said the wire runs under the engine. He believes it isn't absolutely necessary to have the wire because the carburetor has a solenoid that can cut off the fuel to shut the engine. He really doesn't want to pull the engine if he doesn't have too.
I will check it out tomorrow after work.

 

[MossRoad]

Good for you. Sounds like you might have an honest mechanic. Reward him properly if that is the case. :laughing:

 

[J_J]

Seems like I mentioned those valves in three different post.

 

[woodlandfarms]

What valves are you talking about JJ? ;-)

 

[J_J]

Intake and exhaust.

wa****a mentioned the valves

MossRoads mentioned the valves X2

Gravy

Tim_in_CT

 

[woodlandfarms]

Sorry JJ. It was an attempt at a joke. I had seen all the posts on valves. I love it when levity fails.

 

[cqaigy2]

Sorry JJ. It was an attempt at a joke. I had seen all the posts on valves. I love it when levity fails.

FAIL! :laughing:
But Im thinking something to look at might be the valves.

 

[Frank Sorbello]

Here is what I know about the motor.
It runs good when started. Doesn't smoke. Sounds good. Has plenty of power.
The previous owner had it rebuilt in the fall. The hour meter had 715 hrs on it when I bought it.
I listened to all your advice on the board. Did what I knew I could do my self. Talked to Terry at Power Trac, described the best I could all the information I had on the engine. Took his advice on everything, followed it to a tee. Started once with a spray of gas. It started. Next day would not.
Took the 422 to a very reputable small engine mechanic.
He adjusted the valves. Found a bad wire. Thought everything was ok. Had it in his shop for a few days. He got it running.
So the last few days it has been in the mid 40's, she will start.
As soon as she drops below 40 - she won't start. Unbelievable!!!!
Called Robin Subaru. Talked to tech support. He said I need to change the oil in the winter to 5w30 and to buy a heavy duty starter. He said starter doesn't produce the rpms to start the motor in the cold. OK what is the part number. Told him my engine size and year. His reply was there isn't a heavy duty starter for that year engine. Advised I call Terry at Power Trac.
Tonight it is about 35 degrees. I try to start it. Backfiring through the carb and muffler. She won't start.
Just can't believe how good she sounds when she runs. It is just getting it to run. Wish I could have bought a new one.

 

[washita]

do you cycle all of the controls, ie: joystick, treadle, steering, to relieve any residual hydraulic pressure buildup in the system? before attempting to start the engine. mine it will not start below 30 degrees if I forget to cycle the controls, if I cycle the controls it will start at 20 degrees without any assistance, anything lower than 20 degrees I have to jump start it but it also resides outside most of the year with a tarp over it

 

[Marks481]

Told him my engine size and year. His reply was there isn't a heavy duty starter for that year engine..... Wish I could have bought a new one.

You still can! It can be better then new:

http://www.brandnewengines.com/EH722DSF050.aspx



Ask KMA and Vacuous_One how their Fuel Injected 28 HP engine starts in cold weather. Both installed in PT422s.

http://www.tractorbynet.com/forums/power-trac/202389-pt422-engine-swap-completed-pics.html
http://www.tractorbynet.com/forums/...engine-shaking-sputtering-10.html#post2170245

If my engine dies someday, that is what I will do.

So I got to thinking. What about just mounting the Robin EFI throttle body (which contains the ECU) and an electric fuel pump on an existing Robin engine. I think that is the only real difference. Cheaper then replacing the whole engine.

Well, not by much. $480 for the throttle body. ouch. $91 for the fuel pump.

http://www.jackssmallengines.com/Parts-Lookup/20K6240100/2204455/pd

back OT, what year is your engine? Clean up the battery connections, run a heavier gage wire directly to the starter solenoid instead of the two-part with a post like it comes from the. Every little bit can help.

Mine is a 2005, and it also doesn't like weather below 40F. Making sure I run it at least every 1-2 weeks during the winter helps. Heater underneath the engine for an hour before starting helps.

Do you keep it outside or in the garage?

 

[SpringHollow]

stick on heating pads, magnetic heaters, etc certainly will help when it is cold as will synthetic oil. A good battery, cable, and connections also go a long way towards starting.