Volvo Penta 3.0 GLM-C will not shut off

Joined
Sep 7, 2019
Messages
2
Neither the kill switch nor the ignition switch will stop the engine. I have to pull the coil wire to get it to stop. The engine overheated just before this started happening. I've looked for a diode as I have read that this is a problem with the 4.3 engines but cannot find one. I suspect this is due to a mechanical fuel pump.

The alternator seems to be working just fine. The voltage is over 14 when running with no load.

Any ideas?
 

Saline Marina

Petty Officer 2nd Class
Joined
Sep 9, 2014
Messages
162
Just to clarify are you pulling a spark plug wire (high voltage wire) off the coil or are you pulling the 12vdc supply power terminal?

In either case, I believe your problem is related to the 12vdc supply power and its failure to go to zero volts at the proper time. That the kill switch doesn't work suggests there's an alternate source of 12v supply, jumper wire(s) in the harness or a relay contact is welded closed, just to tick off some ideas.
 

bobstoy

Cadet
Joined
Jul 25, 2018
Messages
17
There are some small relays by the fuse panel. Guessing one of those stuck closed
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,286
Water in the fuel can cause this. Just in case it’s unrelated to what you suspect. But usually stumbles and stutters when it runs on with key off.
 
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