1997 Merc OB 115HP - Inconsistent Start - Not Engaging Flywheel

[zooba]

Hey Everyone,

I could use some help with my 1997 Mercury Outboard 115HP which has been experiencing an Inconsistent start and it’s getting progressively worse. I actually had to pull the boat.

I can confirm the following:

The battery voltage output is 12.67 when sitting – It barely drops when I turn the ignition; maybe 12.50 or something like that. Early this year I had to replace the positive battery terminal connector as it was worn out. I also just replaced the starter solenoid out of hope that it might be my issue – but it’s not. When I turn the key, the starter engages and the gear spin, but it inconsistently raises to engage the flywheel. If the engine starts, I can usually crank it up again, but if it sits and I try cranking it cold, the starter gear will not rise. Does this indicate a bad starter ?? As of right now, my plan is to replace it.

What brings me to this forum is another inconsistent problem and I’m not sure if it’s related – once in a while, very rarely I lose power. Meaning I turn the key and I basically hear nothing. Even when I try to lift the motor, the power tilt motor does not engage – but then it kicks back in. The battery terminals are clean and tight. I tried tracing the cables the best I can back through the transom and I can’t see any issue with the battery cables. This might be a completely separate issue.

Does anyone have any thoughts on this ? I’m struggling with it. Thanks in advance !

 

[flyingscott]

Check all your grounds make sure they are perfectly clean. All connections on the motor need to be cleaned.

 

[zooba]

Is it possible that the starter is shorting things out ? The loss of power only happens after cranking the starter and the stater gear spins but does not engage - The power loss does not happen otherwise. I will check grounds - but everything looks very clean and tight on the engine.

 

[WesNewell]

Remove the battery cables and use a wire brush tio clean the ends of the cables and the erminals. Sounds like a bad connection to me. Cleaning the erminals while they are still connnected only clens the ouside of the connection, not where the leads mate.

 

[zooba]

Thanks for the replies - I'm still struggling with this issue and would appreciate additional suggestions:

I removed the positive battery cable, wire brushed both sides and tested for resistance and it was good - I did the same for the negative cable.

I removed the battery and took it to Autozone for testing and they said it was 100% charged and in good condition.

Starter Solenoid has been replaced - Probably didn't need to be

After cleaning all the ground contacts and battery cable I thought I had consistent power and starter was still just spinning and not engaging flywheel - so I replaced starter and it seemed to be working. I put boat back in the water and it worked for a few hours but once I stopped engine and tried to restart it was dead again.

The boat basically has no power to the engine - dashboard gauges work, but weak or no power to the engine starter - power tilt not working, etc. The problem is inconsistent and I agree with others who say it's a connection but I'm not sure where else to look. I believe I cleaned all contacts to the engine at least on the starter and solenoid. Can someone provide some ideas on what to do next ?

Thank you in advance

 

[Chris1956]

It sounds like bad battery cables. Sometimes they can rot out under the insulation. Buy some new, marine battery cables, with ring terminals and try them. Make sure ground on motor and battery are good. Usually positive battery cable connects to starter solenoid.

Check other grounds on motor. Should be from block to starter as a minimum. Other grounds internal to the engine are probably lurking.

 

[zooba]

Thanks again - I believe I might have finally isolated the issue and you're correct about the battery cable. It appears to be the crimp on the battery terminal ring of the positive cable - I don't want to say definitely as I have not fixed it yet and I have been wrong about everything else thus far. However, I was out there this afternoon and when I started messing with that connection I noticed power was restored. I'm planning to try to crimp down a new ring on the cable and probably replace the cable at the end of the year.

What's kind of odd is that I did test the cable for resistance and it was good. I'll update the thread if I confirm the resolution. Thank you

 

[Texasmark]

Start the engine several times in succession to get the wiring hot. Either put a volt meter across the cable terminal with one lead, and embed the other lead into the cable wire....punch through the insulation close to the connector and look for voltage, and or feel for the connection getting hot. Won't measure but a volt or two. Doesn't take much resistance to get hot at 200 amps and record a measureable voltage.

 

[Chris1956]

Cables can test good for resistance, but still cannot pass large amounts of current. I had a spot under the insulation where all but 3 strands of the battery cable rotted away. The ohm meter showed zero resistance, but when you hit the starter, you got very high resistance since 3 strands out of 50 cannot pass enough current to run the starter under load.

 

[zooba]

Thanks again - Battery cables will be replaced. I got things going again by crimping on a new termination ring.