Lister Engine trouble greenmech chipmaster

[samiad]

Im on with getting a new chipper but id also like to repair whatever has gone wrong with my trusty old greenmech chipmaster 202. Has been solid and dependable for years but all of a sudden it sputtered out last week weve struggled to identify the problem but suspect the engine. My dads quite handy on mechanic work as hes tinkered with cars all his life and hes had a look at the engine and described the following...

 

"Ok here goes! Not done a proper test but the compression seems fine on all four cylinders. The valves are open ing and closing ok .when we try to start it seems to spin round easyer than it did before.thinking it might be the injection pump not creating the high pressure any more. Also with the solenoid stop valve disconnected from the from 12v supply in the normally off position a small amount of fuel is emitted from the injector pipes if you undo the nut at the injectors. Fuel will flow from the rubber injector return pipe.when we tried to run it in the normal condition with injector nut undone there did not seem to be the normal amount of pressure and spray but not having messed with chipper engine not to sure what normal is."

 

Does anyone have any top tips for us to try?

 

and does anyone happen to have an engine diagram for the 4 cylinder lister petter in the 202 chipmaster?

 

much appreciated!

[Agi-Smash]

Start with basics, is there any fuel it?

Is fuel pipe in good condition?

Are fuel filters clean? Sounds simple but you would be amazed how many breakdowns i go to and just replace fuel filters.

Is lift pump working?

If its a cav rotary pump check inlet strainer.

Check stop solenoid comtinuity.

There is another way to check pump but unless you are totally competant with the machine i wouldnt advise it

[ashtree]

Do what agi says then when you are sure you are getting a strong air free jet of fuel from the injection pump bleed screws you can try this.

 

Fully undo the injector pipes and pull them back from the injector unions.

 

Crank the engine (you may have to do this for 20 seconds or so) and watch what comes out. There will be quite a bit of froth but you should finish up with a little billet of solid fuel as each pipe injects.

 

While you are doing this look to see if compression gasses are coming out of any injector stub and if so this is your problem. It's not a common thing but injector needles do occasionaly stick and hold off the seat allowing compression to blow back down the injector pipe into the pump and stop the job.

 

CAV rotary pumps (if that's what you've got) don't have delivery valves (one way valves) on the outlet to the pipes so any gas from the engine goes straight into the pump and forces the fuel back.

 

Let us know how you get on.

[samiad]

Start with basics, is there any fuel it?

Is fuel pipe in good condition?

Are fuel filters clean? Sounds simple but you would be amazed how many breakdowns i go to and just replace fuel filters.

Is lift pump working?

If its a cav rotary pump check inlet strainer.

Check stop solenoid comtinuity.

There is another way to check pump but unless you are totally competant with the machine i wouldnt advise it

 

 

 

Cheers, forgot to mention he'd been over some of those things first but thats all good stuff, nice checklist to work on. I'l be back on with an update tonight.

[samiad]

Do what agi says then when you are sure you are getting a strong air free jet of fuel from the injection pump bleed screws you can try this.

 

Fully undo the injector pipes and pull them back from the injector unions.

 

Crank the engine (you may have to do this for 20 seconds or so) and watch what comes out. There will be quite a bit of froth but you should finish up with a little billet of solid fuel as each pipe injects.

 

While you are doing this look to see if compression gasses are coming out of any injector stub and if so this is your problem. It's not a common thing but injector needles do occasionaly stick and hold off the seat allowing compression to blow back down the injector pipe into the pump and stop the job.

 

CAV rotary pumps (if that's what you've got) don't have delivery valves (one way valves) on the outlet to the pipes so any gas from the engine goes straight into the pump and forces the fuel back.

 

Let us know how you get on.

 

 

great info cheers, i'l let you know exactly what weve been upto come tonight and I'l take some pics and vids so you can see what it sounds like and looks like etc.

 

cheers

[PeteB]

I seem to remember that the lift pump is a simple bi-valve jobby. Strip and check that muck isn't keeping a valve partially open. Check the fuel system from the high pressure pump back to the tank, clean or replace all filters including anything in fittings on the high pressure side too.

 

Check that the rack is actually opening and not just the quadrant opening.....

[samiad]

I seem to remember that the lift pump is a simple bi-valve jobby. Strip and check that muck isn't keeping a valve partially open. Check the fuel system from the high pressure pump back to the tank, clean or replace all filters including anything in fittings on the high pressure side too.

 

Check that the rack is actually opening and not just the quadrant opening.....

 

 

oh god....its not the fuel system after all! Full blown disaster by the looks! Check the video of my dad showing me the score!

 

[ame]

[/ame]

 

what do you think could have caused such a calamity?

 

all fluids were topped up, nothing irregular being fed in. Blades are kept sharp in genral (although i had run them pretty dull waiting for saturn machine knives). Ive been lazy with the Anvil, could have done with a new one a while ago.

 

The machine died with a guy unfamiliar operating it on half revvs, I shouted down from the tree to tell him to stop this but he did it a few times, maybe ran it about 10 inutes all in all on half revvs, chipping 3-4 inch beach branches. could it be that perhaps? who knows. Where to go from here. anyone have an engine diagram/manual for this kind?

[PeteB]

Running at half revs wouldn't have done that! Either timing chain has bust causing rising pistons to impact opening valves or it has "hydrauliced" which is fluid on top of pistons meaning that valves cannot open when push rods try hence the bent push rods. Good video and your Dad sounds a great bloke!

 

Wip head off and see is the next thing for this - I'll found out some details from Mac and Jason....

[treequip]

That's not a disaster, I like to see bent push rods, bent push rods means there is probably less damage elsewhere.

 

That's nothing to do with your bloke running it at low revs, more than likely the valve timing has slipped. In engine terms its not a difficult fix.

 

You don't need an engine diagram, push rod engines are as simple as it gets

[samiad]

Running at half revs wouldn't have done that! Either timing chain has bust causing rising pistons to impact opening valves or it has "hydrauliced" which is fluid on top of pistons meaning that valves cannot open when push rods try hence the bent push rods. Good video and your Dad sounds a great bloke!

 

Wip head off and see is the next thing for this - I'll found out some details from Mac and Jason....

 

 

 

Cheers! Could anything im doing wrong on a day to day basis encourage "hydrauliced"/bust timing chain? blades were a bit dull but nothing silly. Just old age?