CAT 3116 - fuel solenoid. Is there a relay?

[cwiert]

I broke down yesterday traveling from Newport RI to Chester, CT. About 30-35 miles from home. Lost the stbd engine. Just shut off without warning.
Seas were pretty nasty too. Limped to shelter behind Fishers Island on one engine and tried to troubleshoot. A marine mechanic friend told me to check the fuel solenoid and see if it would click when you press the start button half way. It didn’t. He had me remove the solenoid, take out the spring and plunger and re install. She started!
But then I couldn’t shut her down when I got back to dock. I had to shut off fuel supply at the racors and starve her of fuel. Good times.

I’m wondering if the solenoid is bad or if there’s a relay before the solenoid that might have gone. I bench tested the solenoid and it seemed to work. I don’t want to buy another solenoid if that’s not the issue. Tomorrow I’ll test power to the solenoid. Just wasn’t sure if there was in fact a relay.

Here’s that part with spring and plunger removed:

 

[Sgrochow]

There is a relay, but not sure if it’s the issue. If the relay goes bad, engine won’t start, not sure about the shut down issue.

This relay is in the “electric” box (not sure what else to call it) on my 3116 Cat 1998. It would be easy to diagnose, just pop the one out of the other motor’s box and try it.

 

[cwiert]

So for me, the relay was the issue. Got one at Napa for $13 and all works as it should again. Napa Part # AR174

 

[Steve S]

When I purchased my 400 DB, Frank Webster advised me to get several of these relays for my spare equipment box. Had them onboard ever since.