2006 Bayliner 185 trouble starting-gctid818424

[ncoffenburg]

Im experiencing a few problems with my bayliner 185. It has a 4.3 mercruiser engine in it. Recently i had to change out the ignition switch that was faulty and the 50amp circuit breaker on engine. The breaker would not pass 12v through it even when it was reset. Put a new breaker on it and it starts.

currently, i put a brand new battery in it and turned the key and nothing. tested 12.4 volts at the starter before i turn the key. When i turn the key i have 0 volts at the starter and still a good 12.5 on the battery. If i take the trim motor wires off of the battery it will start. I put the trim motor wires back on it it robs the starter circuit. isolate the trim motor by itself and it works properly with no lagging in the trim up or down.

If i run the trim motor only on the battery, i see a voltage drop from 12.4 to 11.6 while im toggling the trim. Not enough to rob the starter to 0 i wouldnt think.

Does this look like a bad ground going from the battery to the engine block? i took it off, wiggled it around, put it back on then the boat started and trim worked properly 3x. Now im back to a no start issue as long as the trim motor is connected to the battery. not sure if there is away to test for a bad ground or i will just need to replace ground cables. What do you guys think? Im also only running one battery on this boat as well.

Thanks,

[builderdude]

Was going to suggest you check the negative battery cable for a solid connection at both ends, sometimes cables can become corroded way up inside where it can't be seen. You could use a set of jumper cables connected temporary as a negative battery cable to verify that is your issue. Look at the possitive cable also.