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Merc 3.0 Won't Turn Over

S

Stingray Boy

New member
Can anyone please help me troubleshoot? Engine won't crank or even click. Has happened occasionally in the past but would eventually run. Now she's dead on the trailer. Have ruled out battery, starter, kill switch and starter slave solenoid. it will turn over if I jump across the 2 bolts on the starter slave solenoid. can anyone tell me what to try next? I'm not a mechanic, just a screw-it-up-yourself-er who struggles with electrical issues. Thanks.
 
Re: "it will turn over if I jump across the 2 bolts on the starter slave solenoid"

IF the slave solenoid clicks (no jumper) when you try to start.... bad solenoid..
IF the slave solenoid does not click, check for +12V at the coil connection to ground when you try to start.
IF you get +12V... bad solenoid...
IF no +12, you are loosing +12 "somewhere"... using a meter or a test light ( with one end attached by a long wire to the engine block ground), find out where you are loosing +12... start at the starter switch contact on the ignition switch at the dashboard....
 
Last edited:
Cap Bob,
I replaced the starter slave solenoid and the starter so that's not it. When I turn key on everything works (gauges, lights, blower, radio) except the engine. You noted the 'coil connection'. Could it be the coil (whatever that is...) or possibly something with the distributor or distributor/plug wires?

sandkicker said:
Re: "it will turn over if I jump across the 2 bolts on the starter slave solenoid"

IF the slave solenoid clicks (no jumper) when you try to start.... bad solenoid..
IF the slave solenoid does not click, check for +12V at the coil connection to ground when you try to start.
IF you get +12V... bad solenoid...
IF no +12, you are loosing +12 "somewhere"... using a meter or a test light ( with one end attached by a long wire to the engine block ground), find out where you are loosing +12... start at the starter switch contact on the ignition switch at the dashboard....
Click to expand...
 
Could be the keyed ignition switch itself not making contact when the key is turned to the engage-starter position?
 
DJR said:
Could be the keyed ignition switch itself not making contact when the key is turned to the engage-starter position?
Click to expand...

Could be. Anyone know how to 'hotwire' the ignition switch to see if the switch is bad? Are there specific wire colors to connect?
Thanks DJR
 
My thought was the neutral switch wasn't closed...so move the shift lever around and then back to the detent...

could also be time to clean up the main harness connector (engine harness to helm harness)...
 
To "hot wire" your ignition can be done two ways. (FOR TROUBLESHOOTING ONLY)

At key switch.

get one 10 inch 16 gauge wires, attach alligator clips on both ends.

At back of key switch connect one wire end to RED wire connected to switch. Connect the other end to the YELLOW with RED stripe connection.

If engine turns over then Key switch is defective.

If it does not then Neutral safety switch is most likely bad.

To test slave solenoid and starter,

go to slave solenoid and connect one side of jumper to large terminal on top of slave solenoid with Large RED wire attached.
Quickly touch other end to small terminal (yellow with red wire). If the connection here is a push on type connector, pull it up about 1/8 inch to expose threaded stud and touch wire there.

BE VERY CAREFUL when doing this activity as sparks can occur.

If engine cranks when key switch is jumped at back of switch then key switch is bad.

If it does not crank over and slave/starter test does works then issue has to be nuetral safety switch or issue with wire harness from dash to engine.

if you do this report back with results
 
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