Fuel shut solenoid not engaging

[Rick White]

I replaced a new instrument panel engine was running for about 10 minutes then shut down. When I turn the switch to on the fuel shut off solenoid doesn’t close. I checked the voltage going to it and it’s only getting 11.8 volts.
Voltage at the panel is 13.4v with the switch off and only 12.4v with the switch on.
Is this normal?

Topic

[Rick White]

Fuel shut off solenoid update

Thanks Rob,

That’s exactly what I needed to know.

[Rob Schepis]

Not sure why you are using the term “close” ? Maybe you are relating it to a relay or mag switch with contacts that “close”

What you are describing as to turning the key on and nothing happens is correct. The key on position only energizes the red wire to the solenoid via the ignition purple wire . This is simply the “hold” circuit, not enough amperage to pull the fuel solenoid open, only the white wire coming off the bendix will have the amperage to move (suck-in) the fuel solenoid and then the red/purple will “hold” it there after she fires and you release the starter.

[Rick White]

Fuel shut off solenoid update

I replaced the Fuel shutoff solenoid which was not working and now the engine will start and run.
Just prior to the solenoid problem, I replaced the Engine control panel with a new one from SB Marine with an exact replacement. The original panel and solenoid would engage (close) when the key was turned to the on position. Now with the new panel and new solenoid when I turn the key to on it doesn’t close until I hit the starter switch.
Question is, is that a problem?

[Tony Athens]

Rick,

I hate to say it but your pics leave much to be desired.

But, from the little I see, you have an engine that is, and all the associated wiring, etc., that is every bit of 25 years old ( early 90’s) and all looks pretty original . In so many words, electrical connections , mechanical linkages , etc etc do not work forever in a saltwater environment–Know the term — “Marine Age”??

Only way to sort this out is for you to get into the “nuts and bolts” of the on-engine electrical wiring and this external fuel solenoid, and then understand how it all works…………No one will have a simple to do this– The answer to this is not easy as there are too many possibilities, but none are hard to sort out once you “understand” the system………………………….That is the key……………. Multiple places on this web site to find the wiring diagrams you “need to learn”..

Learn the site as it is all here for issues EXACTLY like you are experiencing.. Best time you could spend if you want to keep using your boat so you can fix simple things like this and not lose a planned weekend trip …………..

How to deal with the Fuel Solenoid on an Early B series with the Nippon Denso Injection Pump

[Rick White]

Here are the pictures requested:

Do you think the solenoid isn’t working because 11.8v isn’t enough to engage?
Seems odd that I have 13.4 volts at the red wire at the key switch, and when I turn the key to on I only have 12.4v. That seems like a big drop, could there be a short somewhere? Maybe the solenoid?
Thanks for your help.
Rick

[Tony Athens]

Exactly what engine?

Good Pictures of the solenoid and adjacent areas

[Author]

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