89 Force 125 ob intermittent starting problem,h sometimes no power to the entire boat

[cg3]

I have a 89 Bayliner Capri with a Force 125 ob motor that is having intermittent starting issues. Before I brought it out on the lake this season it turned over just fine and started right up with the water ears on it at home. I came back out later that day and there was no power to the entire boat, nothing up front and nothing clicking at the motor and I have a 100% charged new battery. I tested for power at all the circuit breakers in the motor compartment and they all had power on both sides of the studs but the entire boat including dash lights, fuel gauge and ignition were not getting juice or the starter. I checked one side of the solenoid and it also had power so I decided to quickly jump the solenoid to see if it would turn over and it did. I then went back to the key and the entire boat up front had power and acted normally and the motor started just fine. I then decided it must be a loose/corroded connection somewhere so I loosened and tightened all the connections I could find in the motor compartment so this would not happen again so I did that and it continued to start as normal.
I decided to take it out on the lake this past weekend and as soon as I got there it did the same thing except jumping the solenoid did not work this time, in fact I am not sure what I did to it but it magically started again and I had a day on the lake starting it several times throughout the day with no problems.
Today I went to start it with the water ears again at home and the same thing happened, I can jump the solenoid and it turns over very fast, the circuit breakers all have power but now the entire boat is dead once again up front and I cannot get it to turn over at all, no more magical starting. I am not sure if it is not getting juice somewhere in the wiring in the motor compartment or if it is an issue up front or wiring in between or some kind of switch? Basically I am lost at this point.
Any suggestions would be greatly appreciated.

 

[foodfisher]

Anytime demons are at work in the electrical system, the usual culptit is bad grounding/earthing. All connections have to be known good. Not look good. Shiny metal to shiny metal.

 

[cg3]

Thanks foodfisher, I will heed your advice and go over everything again with a fine tooth comb and get back to the forum with my outcome.

 

[Jiggz]

There is a grounding wire that is connected to the engine block. This big black wire tends to get loose with the tilting of the engine. But you can't tell by visual looks alone instead you need to dismount it, clean it shiny and also the surface it mounts to. Get a dab of dielectric grease to coat the terminal and mating surface. Lastly, use a split lock washer and bolt it tight again. Try again and you should not have the same electrical problem, unless the loose connection is on the battery terminals itself.

 

[cg3]

Thanks Jiggz, I ended up first starting from the battery wiring going back to the motor. I noticed both the smaller gauge + & - were both spliced for some reason. I cut the splice off and installed new loop ends and the boat fires right up. I did remove the main ground you were speaking and it looked really good but I cleaned it anyway. I then decided to just check everything and found several other corroded connections (many at the ignition switch) and all is well again. Thank you for your suggestion Jiggs and foodfisher, I appreciate it very much.

 

[MickLovin]

Bit late on this one, but yes earth grounding is always first to check, but then you went to where my next step would have been going by your issues, I would have headed to the ignition switch. Which you found corroded and probably the cause of your intermittent problems. I had a similiar experience, but mine was that my motor had a ping when I changed into gear, I eventually found that the ignition switch was holding in the starter for it not to engage but to still spin. It was a slight click of the ignition to get it back to normal, so I decided to spray the ignition switch with a spray grease after using a good electrical contact cleaner.
In all this my battery was also draining when I would idle, as the starter was still spinning. I only noticed this after finding my battery not charging at mid idle. I took my cowl off the motor while out on the water one day and found my starter spinning, hit my ignition switch back a click but it stopped the motor, started it again and it stayed engage until I slightly adjusted the ignition switch back a touch.
All in all keep all electrical connections corrosion free and well maintained with a non conductive silicone spray.