1997 115 HP Offshore turning over slowly and starter sticking

[dacharon]

I have twin 1997 Mercury 115 HP EXLPTO model outboards. Starboard engine has recently begun to turn over very slowly and starter gear sometimes hangs up on flywheel. Starts intermittently. Other engine turn overs and starts fine. The engine with the problem appears to have an after market (made in Taiwan) starter. I have made sure the batteries are fresh, checked that the connections are clean and solid. Wondering if these symptoms are pointing to a starter or solenoid issue? Bad cables?

 

[Texasmark]

Re: 1997 115 HP Offshore turning over slowly and starter sticking

Connections have to be clean and shiny inside, not outside where you can see it. Need to be tight also. Sometimes battery cables get bad at the cable connector crimp. Sometimes the starter solenoid contacts pit and the reduced surface area will not carry the 150 amperes required to start that engine. You only have a couple of volts to spare from a 12v battery and at 150 amps, resistance is out of the question.

Get a voltmeter and start at the starter terminals, both the STUD where the red wire is attached and the STUD (if it has one) where the black wire is connected. You need at least 10 volts at these terminals when spinning the engine in a ready to start condition to make it happen.

If you don't get 10 volts, work your way back to the battery, following the red lead but both can be at fault, till you find where you lost your voltage. Replace the defective component.
A little WD-40 on the starter bendix shaft will help too, but the voltage is the important thing.

While you are at it, whatever you find, go to your other engine and renew it too. Save you trouble later.

Mark

 

[dacharon]

Re: 1997 115 HP Offshore turning over slowly and starter sticking

I followed the advice from TexasMark. I removed, cleaned and replaced all wire connections on the batteries, solenoid and starter. No change. I used a multimeter to check the batteries - 12.6 volts on both. I checked the volts at the starter when cranking - approximately 10 volts. I tried to start the engine several times. I then noticed that the starter was extremely hot to the touch. Anything else I should check before I invest in a new starter?

 

[dacharon]

Re: 1997 115 HP Offshore turning over slowly and starter sticking

I wanted to provide an update for those that were following this thread. After spending a lot of time going through the diagnostics and connection cleaning as recommended by Texasmark I narrowed down the problem to the starter. I was not getting any clicking from the solenoid and the multimeter indicated I had 10+ volts coming through. The symptom of the starter motor getting hot was the final factor. I purchased a new starter, installed it in less than 30 minutes and the engine cranks over perfectly.

Hope this helps somebody else.

 

[Texasmark]

Re: 1997 115 HP Offshore turning over slowly and starter sticking

Your smoking gun as you realized was the hot starter. Glad you got her fixed and thanks for the feedback. It helps the next guy down the line asking for ideas.

Mark

 

[dacharon]

I just put the batteries in and cleaned up the boat to enjoy it for the 2017 season. When I attempted to start the port engine I experienced the same symptoms as I did with the starboard engine 4 years ago. I again went through Texasmark's protocol to eliminate poor/dirty connections or solenoid issues. I also spoke to the mechanic at my marina. He stated that this is a known issue with Mercury engines from this era.

I have ordered a new starter. It will arrive and be installed on Friday 6/2. I will provide an update if it does not fix the problem but i am quite confident that I have figured out the problem.

Happy boating!

 

[Texasmark]

Keep us posted as we can help you through "The Rest of the Story" (Paul Harvey) if the starter doesn't fix it.