Lister Engine Forum

Lister Engines => Petteroids => Topic started by: grebma on July 24, 2017, 02:43:48 AM

Title: lpws2 intermittent power loss
Post by: grebma on July 24, 2017, 02:43:48 AM
hey all.  Great forum and I appreciate the info on this site.  Newbie here.  I purchased a Schweiss zero turn lawnmower last year with a LPWS2 engine.  Animal of a machine as it tackles grass well.  over 800 hours and hour meter not working when
I got it so who knows.  The problem I'm having is it's running hot after about 45 minutes with some black smoke at that point and some serious loss of power to the point where it quits running.  This started end of last summer after I had lots of water in the fuel (diesel bulk tank had water in it).  It quit on me and I drained the tank, lines, and replaced fuel filter.   This spring it would run 210-225 degrees and I would shut it down at that point.  Pressure washed the block and found rust running below the line where head meets block.  Looks like the head gasket is bad/leaking and may be the cause of the overheating. 

Some new parts recently:
fuel filter
oil change with new filter - 10w30 Shell Rotella diesel oil (this was what previous owner ran- i just learned it should be 15w40 right?)

This weekend I used some head gasket repair (followed the directions exactly)  and ran it today.  Temp stayed below 190 degrees which was great.  Head gasket fixed (I know - for now right- short term fix).   But I could run it now for about 90 minutes  before it started blowing smoke and a bit of power loss.

When this happened I deactivated the mower deck, throttled it back to about 1500 rpm and left it run so I could take some temperature readings on it.  All readings between the 2 cylinders were even- on glow plugs, block, intake, injectors, etc.  Except on the exhaust manifold:  530 degrees on the rear cylinder (closest to flywheel) and 330 degrees on the front cylinder.  So obviously one cylinder is not playing nice with the other.

Could this be a bad injector?  Which one?  Could it have been damaged with the water in the fuel incident?  Could it be valves need adjustment?  I have no manual for this adjustment so any advise on specs would be good.

Hate to give soooo many details but it may reduce questions.  I really like the machine.  It's ugly but it has everything I need- zero turn, single joystick, 72" deck, etc.

Any help you may have is greatly appreciated.   

Title: Re: lpws2 intermittent power loss
Post by: glort on July 24, 2017, 07:03:40 AM

I'd Suggest instead of guessing at all sorts of random things, you diagnose in a methodical way and work your way through.
 First thing as you suspect the head gasket ( you didn't say if it's using water) is do a compression/ leak down test.  Next would be have the injectors tested/ serviced.  Check the radiator for blockages and have it cleaned if in doubt.

Work your way through the thing eliminating possibilities.
 Do a through and proper maintenance and service to start and check from there.
I doubt water in the fuel would cause the thing to overheat. If the pump or injectors were damaged chances are it would not run or it would knock.
Don't underestimate the difference between new and worn injectors. they can transform the way an engine runs and if you don't know when the were last done I'd throw a pair in there anyway.
Title: Re: lpws2 intermittent power loss
Post by: dieselgman on July 24, 2017, 03:39:33 PM
Good power unit for a little machine like that! There are thousands of them around surplus from military disposals... no problems finding replacements. We stock all parts for them as well.

A quick leak-down test will show you any faults in cooling system seal, quickly and accurately. If you have an intermittent issue, then try doing the test with engine warmed up first. Don't forget to deal with water pump and thermostat... 6,000 hours replacement of these parts is almost mandatory for safety on these engines. I am referring to the leak-down test where you install a small hand pump and gauge tool onto the radiator filler neck and manually pressurize the system... you can then observe any leakage and any loss of pressure under controlled circumstances without harming the engine. If you have head gasket issues or have overheated the unit, it is common to warp those cast iron heads. Your LPWS head cannot be easily re-surfaced and the usual fix is a new cylinder head.

The other fueling issue... injectors will usually fail first because the nozzles will get sticky and no longer atomize the fuel properly. The pumps will also suffer with water contamination and they can cause all sorts of weird (and intermittent) performance and governor control issues. It is not too difficult on a twin cylinder to figure out what is going on... be glad you don't have 4 cylinders to diagnose. The parts can be bench tested, or simply replaced - step-by-step while checking for symptoms and operation.

Title: Re: lpws2 intermittent power loss
Post by: grebma on August 14, 2017, 07:01:46 PM
just some updates here.  I had the injectors professionally cleaned and they checked out fine with tolerances, etc.  $34 well spent for peace of mind.  While injectors were out I did a compression check on the cylinders:  400 psi on each so that is good to see.  Changed oil to a 15w40 diesel oil (Shell Rotella), new oil filter. 

Put it all back together and ran it for about an hour mowing lawn.  Seemed a little low on power but never got over 190 degrees and never blew any black smoke.   Hmm could it have been the injectors and oil?  I still feel as though I should adjust the valves if this is possible.  Does anyone have specs on valve adjustment in this engine?

I have not pressure checked the radiator yet as recommended here.  Need to get a kit for this or borrow the equipment for it.  It is using a bit of coolant but I don't observe any white-ish smoke other than startup.   

Some resolution!!!!!  But still feels a bit down on power.
Title: Re: lpws2 intermittent power loss
Post by: dieselgman on August 14, 2017, 08:05:24 PM
Hydraulic valve lifters = no adjustment possible.