thwaites 4000 newbie with a problem.....

[agrifabs]

hi all, gotta say this is a great site.

i have recently purchased a thwaites 4000 dumper,
when i brought it off the trailer itconkedout, great i thought! took filter off and it was chocked right up,
it run again after that but after about 20 mins it will slowly conk out, and its as though it hasnt got enough go in it to drive,

today i have replaced all of the fuel lines with clear plastic and put a cav296 type filter unit on it, pulled tank off and cleaned it out, and put new diesel in, blead it through and its great,

but.. after 20 mins it slowly wants to conk out, and again its as though its not responsive enough to actually drive,

i was thinking, is there anything in the 2 pumps that could be sticking? or is there a gauze anywhere that i dont know is there? its a lister ph2 handle start,

could someone please help me?!


regards

chris

[essexpete]

Someone with more experience will with luck come along but have you tried filling the tank to brim and bleeding through to the pump as the tank is above the pumps? When it conks out will it start without rebleeding when cooled down? Has it got power when it initially runs?

[agrifabs]

cheers for the reply,

the tank is full, and it has to cool down for about 1 1/2 hours before it will start again, its as though its being starved of fuel but i know that from the tank upto the pump it is flowing fine (all new),

when its running it just seems gutless,

thats whats making me think that there is something in the 2 pumps that is wrong, gauze or nsomething stuck,

thanks again for reply

chris

[Jeremy Rowland]

Hi Chris welcome to the site it sounds like you have done a pretty thorough job of cleaning out the fuel system, whilst I have no knowledge of this system I would for a general fuel system consider the following points; as you have said there may be a gauze filter on the injection pump, the fuel tank breather may be blocked, if there is a lift pump (I don't know it may be a gravity feed) then I would suspect the lift pump or at least check the gauze filter which you can usually find in a lift pump and I would also check the air intake is free from any obstruction.
These are just a few ideas but there are people on this site who have far more experience of working on this type of kit and may be able to offer you some better pointers.

Jeremy

[Julian]

hi but.. after 20 mins it slowly wants to conk out, and again its as though its not responsive enough to actually drive,


regards

chris

Next time it starts to 'conk out,' take the cap off the fuel tank - sounds to me like a good chance the breather is blocked here, check also that the fuel is still exiting your filter with suitable flow.

You maybe on the right tracks regarding a 'last-chance' gauze filter. Certainly the Lucas DPA pumps have one inside the inlet union but I don't know about PH2's. There is an on-line PDF manual somewhere for the PH1/2, failing that try the Stationary Engine Forum for specific PH2 advise.

Julian.

[FOWLER MAN]

Hi Chris,
If you have a Lister/Petter PH2 it will rely only on the one filter which you have replaced with the larger capacity CAV unit, there normaly are no additional gauze filters.
It would normaly be gravity feed so no lift pump or lift pump gauze to worry about either.
I think Jeremys suggestion of a blocked tank breather is favourite , (they breathe through the filler cap,) you appear to have checked everything else.
I cant think there could a problem with the pumps. Are the sealing washers on the pump connection banjos OK?
The only other thing I have seen is a faulty injector allowing cylinder pressure back into the fuel system and forcing the fuel back, this is very unlikely with a two cylinder engine as it would be pretty obvious if one cylinder was down.

Fred

[agrifabs]

hi, i have had the injectors out today and one isnt atomising as it should so i have a new nozzle on order, but i also found that one of the injection pumps isnt performing as well as it should be, so that will go to the shop tomorow to be reconditioned,

i think the injector was just filling the piston up with diesel causing whats known as hydraulic lock therfore resulting in it slowly conking out after 15/20 mins,
i checked the cap and its ok,

[essexpete]

I would have thought that over fuelling or build up would have caused knocking and smoke?

[FOWLER MAN]

I would have thought that over fuelling or build up would have caused knocking and smoke?

Yes definately Pete,
The fuel would be blown through the exhaust, (burnt or not), before it could cause a hydraulic lock anyway.

[agrifabs]

hi all, thanks for the replies! just had the injector and pump back from being refurbed, put it all back together but when i put the 'link that attaches the two pumps back on one of the injectors stops atomising, so i take it that my problem now is that the linkage needs adjusting so both pumps are working and not one working and the other in stop poisition, if that makes sense!

i will npull the injectors back out tomorowand reconnect pipes to them and will turn her over by hand and adjust the little linkage untill both injectors atomise, does this sound right way to do it?

regards

chris

ps, i have found out that this dumper appears to be a thwaites 6000 and not the 4000 like i though previous, it has the same mudgaurds and two tipping cylinders as the 6000 i seen on ebay.