What to look for when testing a used machine

   / What to look for when testing a used machine #41  
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.
 
   / What to look for when testing a used machine #42  
Throttle cables go out on the PT's. Mine got gummed up over the years.
 
   / What to look for when testing a used machine
  • Thread Starter
#43  
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.
 
   / What to look for when testing a used machine
  • Thread Starter
#44  
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?
 
   / What to look for when testing a used machine #45  
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.
 
   / What to look for when testing a used machine
  • Thread Starter
#46  
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.
 
   / What to look for when testing a used machine #47  
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.
 
   / What to look for when testing a used machine #48  
Has anyone set the valves correctly ????
 
   / What to look for when testing a used machine #49  
...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.
 
   / What to look for when testing a used machine
  • Thread Starter
#50  
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.
 
 
Top