Right-arm fast
Member
Perhaps the chain slipped whilst you were removing or installing the pump? I'm suprised one tooth made the valve hit the piston though! At least you found the problem, everything's is nice and clean.
I think you could get it metal sprayed and ground back to original specs. There used to be a co in Burton on Trent who did it. I have only had the rear crankshaft seal surface done not a cam.
Swan Vesta's…Any word ................
No the "knock" was sorted, it just hunts at idle/low revs and no matter what I do to it I can't stop it, can spray Easy Start all around the venturi etc and engine revs dont change so no air getting in. Changed springs/plungers etc on the pump, no leaks there either, new lift pump/filters. I do have a feeling that maybe a weak injector which in turn leads to almost a misfire (but not quite) and this upsetting the balance between spring on the diaphragm and vacuum and then leading to a uneven hunt/pulse but I will find out soon (I do worry that the ploughing season will be over mind!!)Sorry to hear that .................
If you don't mind me asking, is it still knocking, or is it back at the hunting?
Yes, I would say more like 600 to 1200, if you adjust the lever on the side of the injector pump it makes no difference to the hunting, just shifts it higher up the rev range. The plunger was originally seized and as such there is a slight bit of pitting but nothing too bad. Compression is good at 300 psi on all pots (new rings maybe not bedded in yet) so one would just start to think about fuel.So the fault is only at sort of 6 -800 revs ?
Yes, it runs ok but I need good low end throttle control for match ploughing, as we like to go slow!!! Filter disconnected makes no difference. I have tried opening the fuel line bleed whilst running and again makes no difference, wasn't aware there was any pressure control on the actual lift pump, just 2 one way valves and then a restrictor on top of one of the fuel filter bowels going back to tank via injector overflow ports.And you are happy with the engine and the way it runs, only its hunting?
If so, I would think its pump/governor control rather than engine.
The air filter on or off makes no difference?
Did you try opening the fuel line to the pump just in case the pressure control on the lift pump isn't working, or set to high?
No play in any of the linkages, made sure it was all done properly and slop free. I could assume that there should be a vacuum pipe damper which would do as you say and stop the hunting but I am not aware of any on any of the engines I have worked on. Pump was gone through having new elements fitted, calibrated and phased and then checked over again last week.might be worth restricting the vacuum with a small tap in the airline near the governor housing which you can slowly close to even out and maintain a constant vacuum in the diaphragm chamber rather than it being pulsed when the inl. valves open. Am assuming the fuel pump has been checked properly and there isn't a damper missing or play in any of the linkages which would let the rack move or the plungers rotate.
Yes Tom, it is all connected and if you disconnect it and move by hand all it does is move the surging up the rev range, plunger is free and you can feel when it comes into contact with the diaphragm.Is the link and rod thingy fitted @MrNoo r/h side of diaphragm -back to throttle linkage?
Ive a memory of something in there that tried to balance out hunting at the idle /low vacuum pull .?? Adjustable ? Plunger inside if free