Fired the ole girl up for season, Inspected and warmed up. Worker great for about 5 minutes.. When touch travel levers it loses power and stalls. Replaced fuel filter with no help. Is a real pain to get restarted and thought was pulling air into fuel supply. Dealer suggested lift pump or air leak. Drained fuel and removed all fittings, hoses, lift pump, and water trap. Replaced lift pump and primer, double clamped hoses too no avail. Once starts stalling from lever movement it struggles to recover and generally will stall out even if barely move a travel lever.It does not sound like a load is pulling down, more like fuel is being derated. No black smoke from load. Sugestions anyone with experience on these vintage pieces??
When you changed the lift pump did you notice the banjo bolt on the bottom with the filter in it?? I had 1 in the shop last week that had a new supply pump on it.. the water was so bad in the fuel that it stuck the plunger piston in the new SP. When it stalls, can you use the hand primer to restart it?? I'm assuming you have a Zexel inline fuel inj. pump..?? They have an overflow valve in the return side, on the inj. pump, going back to the fuel tank. You can either take it out and check it for a broken spring OR loosen the nut and use the hand primer to check the opening pressure..it should be around 25psi. Personally I would loosen the nut on the Overflow valve, pump the HP till I got fuel, run the engine, get it to stall and recheck the overflow valve.. loosen the nut and see how many pumps it takes to get fuel BACK to the overflow valve. IF its only 1 or 2..the fuel IS staying in the circuit.. and you'll need to look elsewhere for your problem.. IF it takes 8-10 pumps of the HP, you have a fuel system problem.. and the supply cant keep up w/demand.. You could loosen the nut on the OVFLO and get a helper to watch and see if it "pulse's fuel" [squirts] when your cranking the engine.. at least you'll know the supply pump is working..
Filter in banjo bolt was cleaned. As mentioned the fitting into tank, Lift pump, and prime pump were serviced. Double clamps were installed on both low pressure hoses. Perhaps the long hose from tank could be worn thin and allowing a air leak into line. It does take numerous pumps to get fuel out of main filter port. It does seem to have air in filter and is reason for excess pumping on primer pump. More inspections to be made. I restate it is a very quick derate when just barely touching a travel lever.
Does it die just with the travel or with dig functions also?
The travel functions are the most pronounced intially. After recovering from a few travel efforts, The boom movement will cause stalling also. It will go from a full dig effort to the slightest travel lever movement and will stall out with no black smoke in less than 2 seconds. I agree, it sounds like a air leak and will presue that futher..
did you ever discover the reason for the stalling? I have my 270 doing a similar thing