Intermittent electrical problem Mercruiser 3.0

[Natesdude]

I have a 1997 Starcraft pontoon boat, Mercruiser 3.0 , with an on again/off again starting issue. Last year I turned the key, nothing happens. Later on turn the key and the engine fires up. Next week same issue, nothing. The first mechanic changes the starter and it works , then next week the same issue, nothing, like the battery has been removed. Battery has 12V. He thinks it may have a crimped wire. He keeps putting me off on working on it, so I take it to a second, highly recommended, mechanic. He changes the already changed starter, and it runs for a while, then the same issue crops up. In the meantime I have carb issues and have to have it rebuilt. Once thats done, I take it out on the lake this past weekend, it starts right up, and I run it for about 30 mins with no issues , and when returning to the dock I throttle back to idle and it dies. Turn the key and nothing, not even a click. I manually load the boat, and after pulling out I decide to see if the trim will go up, so I turn the key just enough to get power to the acc and the trim goes up fine. Try to turn the key to start it and it clicks but doesnt turn over. Second try same thing, a click but no ignition. A third and fourth try I get nothing again, no click, like the battery is removed.

I'm thinking replacing the key switch is a good start, maybe replace the wiring from the key to the engine, but after that I am out of ideas, and both mechanics seem befuddled. In their defense it started both times I picked it up, so I guess if it isnt doing anything wrong there isnt much way to find the issue.

Any ideas or solutions from having the same issue would be appreciated. As it stands I am going to change the key switch, then start taking readings with a voltmeter to see if voltage is stopping short somewhere.

Thanks

 

[alldodge]

Welcome
And the 2 Mech you found don't go back to them, especially the 2nd. First replaces starter and 2nd does same thing, good grief

My first guess with on/off and no power is the key switch, next would be bad connection. Easy to find with a voltmeter

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Both mechanics shoulda started by cleaning both ends of both battery cables to shiny metal Clean,.....

 

[Natesdude]

Thanks for the replies. Sort of what I was thinking but I wanted some input. Has to be something between the battery and the starter, and doesnt seem to be a whole lot there to go bad. What confuses me is the 2 different reactions when it doesnt work. Sometimes I distinctly hear something clicking in, sometimes there is nothing at all. Its not uniform.

The first starter change wasnt a waste. Sometime previous to me a regular car starter had been put on with an assortment of spacers, washers, and Home Depot bolts. The guy showed me the pics and the parts he removed. The second one, yeah. He did that without letting me know what he was doing. I was trying to get the boat back for Mem Day weekend with a bunch of family at the lake lot over the weekend, and figured if that fixed it I would return to the first guy with questions and a request for a refund. But then carb issues started and Ive been dealing with those since, seem to have finally worked them out.

Ill be checking all this out this weekend. Have a new key switch coming in before the weekend.

Thanks all!

 

[Scott Danforth]

Fire your mechanics

Start at the battery with 150 grit sand paper in one hand, and wrenches in the other. Remove every connection, sand it so they are clean and shiny enough your mother in law would eat off them. Then after you tighten that connection, seal it with marine electrical varnish.

Then move on to the next connection.

Repeat until you get all the way to the helm and back. Every battery cable connection, every harness pin/socket, the buss bar under the helm, etc

It will take a whole weekend

Pontoons with I/Os suffer more corrosion issues than other boats because it's nearly impossible to keep the bilge clean

 

[Bt Doctur]

by the way the key doesent work the starter directly. power goes thru the slave solenoid first then to the starters solenoid