Fuel Delivery problem on Johnson 60 horse

Just on that using "gasket material" be aware things like silastic etc dissolve in petrol & will just block the carbs.

As to using a different pump if it will physically fit when given a vacuum pulse it will pump fuel but be very careful because at high power if it doesn't get "enough" fuel the engine might run lean & that can wreck it. Is there an outboard wrecking yard near you?? maybe get the "correct" one secondhand & try it?? Even an electric fuel pump (should be marine rated .. but)

Maybe try pumping the bulb with the line disconnected from the tank(s) & the line to the carbs off, that way once there's no fuel in the line/pump system, you can block off the outlet to the carbs & should be able to find any leaks as you keep pressure on the bulb. (air leaks out much easier & more noticeably than fuel) while there's no fuel in it try to apply some suction to each section (suck on the pump outlet with a finger over the inlet & your tongue should hold pressure for a "short" time, no crude comments needed:-)) Re-check the oil side is really blocked off because the "O" ring on the plunger "will" leak.

If there are no leaks of air under bulb pressure & given you've replaced the hoses etc so it's not sucking air at any of the hose connections??? You're happy it's not the non return valves or vent in the tank(S), the diaphragm is OK? then;

are you sure the vacuum line is delivering a good clean pulse signal, they have an inline valve to stop a backfire from damaging the plastic pump; is that clear & not stopping the crankcase pulse??

Good luck

K

Tom G.

Heh - this is going to sound strange, but try a new hose from the tank to the engine first.

The primer bulb on the hose may be loosing pressure.

My bad.

You've done the fuel pump you say?? so if the problem persists but then comes good when you squeeze the bulb check;

(1) Before you outright replace the fuel line, particularly the connections (both ends). If it's a plug fitted line, the small "O"ring seals leak & allow air to bleed in.

(ii) The fuel tank(s) has a one way valve in the outlet which can get blocked &

(iii) The air vent into the fuel tank might be blocked (partially it has a very fine anti spark gauze in it)

K

K

That's the design issue with the VRO, all that separates the oil from the fuel is an "O" ring on the plunger, so once that "O" ring leaks then fuel can back flow into & dilute the oil, or if there is no oil there (as might be the case with your system) then it will suck air into the fuel.

If the VRO is no longer needed make sure the oil supply line is properly plugged so it can't deliver air instead of oil.

Apologies for the extra post:-)

K

It doesn't seem likely that it's somewhere on the engine. It still could be the tanks or maybe even the fitting where the hose attaches to the tank. You might want to remove it, tape it with teflon and reinstall it.

I know this is also going to sound stupid, but when you pump the bulb, do you do it horizontally? As odd as it may sound, on my Johnson 25 which has a new hose/bulb assembly and I have to tilt the bulb up and pressurize it - the pressure won't hold if I hold it horizontal.

You might also want to check the filler cap gasket and the tank vent - the tank vent may be clogged.

Other than that, I can't add much to what has already been done and said.