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Mercruiser 5.7efi won't start

M

Michael Moffett

New member
please help?

summary -
engine won't crank. was intermittent - now maybe officially broke.
key on, gauges on, I get the diagnostic beep - my fuel pump starts.
turn the key and I get a small voltage drop but no clunk or anything.
I have checked fuses in engine compartment.
I have lightly looked over main connections to starter but haven't yet gotten to truly checking them out. (that's tonight)

story -
I have had an intermittent starting issue and was convinced I had a neutral safety switch going bad.
for about a month, occasionally, when I turned the key nothing would happen. I would "wiggle" the shifter and it would start.
I know I should have investigated further, but I didn't.
this was not everytime - more like 1-4/5 times I would start the boat. and usually, would only do the first time I would try to start.
btw - this seemed much worse when I came back after one extended 10-day away from the boat business trip.

yesterday - while out with my wife - of course.
after stopping for lunch it wouldn't start. no amount of wiggling did anything...
ok, no problem - remove the neutral safety switch and cross the wires. nothing. no start.
went back - checked all fuses etc... no issues found.
it started... back to the dock quick - and now won't start at the dock.
 
You'll have to do the thorough, get dirty and sweat checks to find your issue.

I'd start by making sure you have a solid ground connection between the battery and the engine block - clean, tight, and no voltage drop when you try to crank the engine...once that is done, you can trace the +12VDC from the key switch back thru the yellow/red wire to the slave solenoid and the starter itself.
 
makomark has steered you in the right direction. Verify that the solnoid is getting 12 vdc when the keyswitch is turned to the start position. Fried internal contacts from high current in the slave solenoid will cause intermittent starts.
 
Thanks for the input.
I have googled today as well.
I think I will invest in a slave solenoid on the way home today and see what I find.
you are both right, I need to do the hard (and hot) work.
Thanks for the tips!
 
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