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Volvo Penta SX 5.0L efi intermittent will not crank

r49floyd

New member
Have replaced starter, starter solenoid, ignition switch, and battery. Problem still pops up randomly. Boat starts and runs just fine....sometimes. Other times, you turn the ignition key to first position....gauges turn on and look good, volt meter on the dash shows just below to just above 12v. Turn the key to start motor....nada, zilch, nothing happens! Kill switch on the dash works. When that is out, all the gauges go back to zero. Put the kill switch fob back in place and gauges go back to working. Jostle the throttle in and out of forward and reverse, center it to normal....no effect. There are five round red circuit breakers on the engine....press on all of them....nada. Let the boat sit overnight. Turn the key...presto! the engine roars into action!! Have been thru this scenario a dozen times now. Boat starts and runs multiple times....then it won't. Sometimes while it is hot, and sometimes not.

I'm thinking there is a bad ground wire involved somewhere? Either in the kill switch, or the throttle/fwd reverse lever, or somewhere else? Question #1...how do I debug this? that is...how would you go about finding a bad ground connection? Question #2 is it possible to bypass all the interlocks and "hot start" the engine? Any suggestions will be greatly appreciated!!
:confused:
 
Things I have seen that will do this...

Crummy battery switch ( my experience is that the "Blue Sea" ones are more reliable than the "round ones") .

Poor quality ground connection to start battery. This cable should be a single marine grade cable directly from the negative terminal of the battery to the engine block. Given labor involved, I'd just change this cable out for a new marine grade one making sure it is a direct connection from the engine block to the start battery and that the connections are CLEAN and tight...BTW... don't use wing nuts on the battery connection.

Check the positive cables while you are at it.
 
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