Testing/bypassing W46 Shut Off Solenoid

[tdoster]

Originally Posted by bcboomer

I'll take a look at that little filter but the fuel I have coming out the return line had already gone through it and there was more than enough volume to run the motor.
I can't see any movement at the solenoid because it is an internal plunger completely contained in the solenoid. An internal spring pushes the needle into the seat to stop the fuel flow and power to the solenoid should retract it and allow fuel to flow. The motor started and ran fine for a few minutes then stopped dead. I think fuel starvation should have shown as rough running.
I'll dig back into the wiring and if I can't solve it that way I'll pull the solenoid and remove the needle.

If you pump the manual pump on top of the primary fuel filter, does it pump? Remember an issue with one where it would suck air.

Crack the injector on the high pressure side and try and start the engine. Even though the lift pump will circulate fuel, you will see the difference between the high pressure of the injection pump and the low pressure self priming of the lift pump.

In any case, crack them all like you would prime a non-self priming diesel, crank and see if you get pressure.

I had Westerbeke build a new harness for a W46 last year for a couple hundred bucks. The one we replaced had a lot of cracks and corrosion. Don't count that until you jump the solenoid.

Also, if you find you need an injection pump, I have one on the shelf that is rebuilt for the 2nd gen W46, which you have.

If you are getting fuel squirts while cranking, I would do a compression test just so you can rule out head gasket, etc. and truly concentrate on fuel. Easy to do on that motor. Pull the glow plugs and connect there.

[bcboomer]

The harness sounds like a good investment just for piece of mind. I'll contact them.
I don't think a pump problem or blown head gasket would act this way. I've seen lots of blown head gaskets and they normally pressurize the cooling system. Coolant is clean and level hasn't changed. Nothing blowing out the recovery tank.
Low compression should show as lots of smoke and hard starting.
Oil or temp switches seem the most likely candidates and I'll check/bypass them as soon as I can.

[bcboomer]

Thanks for the responses. It turned out to be the oil pressure switch. I bypassed it and the motor fired up and it ran fine. A new one is reasonably priced so all good.

Westerbeke, in their infinite wisdom, don't seem to have a wiring diagram that matches the 12 connector harness, admiral panel and fuel solenoid. My harness has had 2 wires left unconnected. I'm hoping a new harness, connected as intended, will work OK.

[Blue Stocking]

I have a W46 in Bluestocking, purrs like a kitten. I stripped and rebuilt it a few years back. What oil pressure switch prevented your engine from starting ?

[bcboomer]

Blue Stocking

It's the # 033935 oil pressure switch on the oil filter adapter. My version is a 2 blade, normally open switch. It only makes a connection with more than 10 psi.
If you have the 8 wire harness you might have a single connector version.
I think I'll add a bypass circuit for this and the temperature over-heat switch so they can't force a shut down in a dangerous situation.

If this switch had failed a half hour sooner we would have been in the Fraser River sharing a narrow channel with tugboats, barges and log booms