Popping Circuit breakers while starting

[paulrfrancisco]

First, its a 1990 30' Cruisers with a Merc Cruiser 7.4L. The DC panel has a on/off/circuit breaker type switch to control the DC to the Ignition system.

While cranking, intermittently the circuit breaker will trip. It doesnt happen all the time. sometimes in a second, other time after 5-6 seconds, yet others not at all and the engine starts just fine.

I had a mechanic look at it and he says the battery and starter connections are all clean and tight.

My thought is a bad Soloniod on the starter. Is this possible? As I understand it, the ignition switch sends 12v to the solonoid and then that causes the contact within it to make the connection between the battery +12 to the Starter motor. So if I understand this, the only thing that could be causing the circuit breaker to trip is the draw from the Solonoid to keep the secondary contacts closed for cranking. I cannot see the +12 feed from the ignition switch to the coil as causing any additional unusual draw on the circuit breaker, so I'm leaning toward the Solonoid.

What are your thoughts. If someone has a wiring diagram for the 1990 MC 7.4Bravo, I'd be interested to take a look at it.

Thanks,
Paul

 

[chiefalen]

Re: Popping Circuit breakers while starting

Any wires with the insulation stripped off, grounding out?

The grounds were checked also, and cleaned?

You would not believe the problems bad grounds can cause and it's a 18 year old boat.

 

[paulrfrancisco]

Re: Popping Circuit breakers while starting

I asked the mechanic, and I assume he check hot and ground wires, but he said the wires were clean and tight... I actually havn't look my self.