1973 165hp Inline 6 Mercruiser I/O ignition/starter solinoid problem

[N211DW]

Good morning,

I have a 1973 Mercruiser in my 22' Starcraft Holiday. The engine runs great! Oil temps were a bit high this weekend so I am going to change the impeller this week before out next outing this weekend and hope that fixes that. But here is my bigger problem.

I have only had the boat for a month and it has never had a problem starting. When we were launching the other day, i put the key in the run position and all the gauges and lights came on. Moved to the start position and nothing. Tried a couple times and then randomly it started. Engine idled great, I did not think much of it so we went fishing. After fishing for a while we decided to move spots... same thing, starter wouldn't engage.

Good new! I had a big set of plyers, and jumped the starter solenoid... stared right away. Ordered a new solenoid, replaced but still no joy. The only way I can start it is by jumping the solenoid.

What would you guys do? Im not sure if the ignition key deal needs to be replaced, but like i said, the run and off positions work. Nothing with the wires or electricals changed. I had the engine started 2 days no problem before this happened, the only thing that I could think of is that it rained the day before we took they boat out.

Also, the battery is only 2 weeks old, an Interstate 24HXD I believe is the model (was $130)


Thanks in advance!!!!

 

[Redtruck12]

Could be a couple of things. First thing I would suspect is the shifter switch ( neutral interupt) and or adjustment of the shifter cables.
how knowledgeable are you with wiring/testing?

 

[kenny nunez]

Check the “boost” solenoid located under the exhaust manifold. Get a test light and have someone turn the key and see if there is current to the small stud with the yellow/red. Be sure to remove the coil wire before you perform this test. If there is current to the wire then the boost solenoid is the problem. They are not the automotive type, they are marine specific and have a non grounded base. If not then the start checking the ignition switch and neutral start switch in the control box. If the control box is a genuine Mercruiser part they very rarely have a problem.

 

[Bondo]

Ordered a new solenoid, replaced but still no joy.
What would you guys do?

Ayuh,..... Welcome Aboard,...... I'd grab my test light, 'n See where there's power, 'n where there ain't,.....

As you've already learned, no sense in replacin' perfect good parts,.....