115 HP Evinrude Intruder starting problems

[AaronM]

1996 115 HP Evinrude Intruder. When I try start my boat, once in awhile (doesn't happen every time) the motor won't turn over, all I hear coming from the motor is a humming sound. It will continue to do this until you hear something "catch," then it finally will turn over and start. It's tough to describe the sounds I'm hearing, but humming noise is the only thing I can think of. Anyone have any ideas? Thanks much!

[boatfixer]

Weak battery

Poor wire connections, corrosion, or bad ground

Dirty or worn bendix

Starter beginning to fail

[Surface Tension]

What your hearing could be the solenoid. Low battery or bad connection. I'd start by cleaning all the connections. Battery, solenoid, starter, and ground.

I was typing while you were.

[boatfixer]

great minds think alike

[Valv]

It can also be the bendix gear that won't slide up to catch the flywheel. Try to spray some WD40 on the shaft where the small gear on top of starter slides. You can also help with a screwdriver to pry up a bit, lightly, to help it get unstuck.

The humming sound could be the starter spinning "free"

[Surface Tension]

If the humming sound takes a few seconds to stop after you turn the key off then it would be what Val suggested. The bendix is not engaging.

That could happen from a dirty shaft and cleaning it will cure that. That gear needs the correct amount of thrust from rotation to engage.

Dirty or corroded electrical connections will also cause that symptom. So will a starter thats starting to fail. Normally stuck, warn, and dirty brushes are the culprit there. Many times its a combination of all of the above that lead to the bendix to not engage.

In conclusion, a healthy starter with a some what dirty shaft will engage without problem. A starter thats on its way out will need that shaft to be squeaky clean.

[AaronM]

Thanks for the responses guys. How much would a new starter run? I like the sounds of a new battery better than a new starter, the battery is a few years old and these problems started after I began plugging in my Expedition C through a cigarette adapter thats hooked up to my main starting battery, maybe that had something to do with it?

The humming sound would only happen when I was turning the key to start it. When I turned the key off, the humming stopped right away. It worries me that I had to hold the key to turned on and wait for something to tighten by that catching sound.

Thoughts?

[Surface Tension]

Pull the engine cover off. Look to see if the small gear on the starter is jumping up and making contact with the flywheel when you turn the key. If it is and it makes that humming sound you have issues with the starter. First clean all the connections like said earlier to eliminate that but more then likely the brushes are warn or stuck from dust and or grease. I wouldn't hold the key like you are because your making the situation worse. Whats its doing is arching in one spot and fusing till it can make enough contact. That creates a lot of heat and wear. If your not capable of cleaning and changing the brushes any shop that repairs electric motor and alternators can. Till then hit the key and back off if it doesn't spin, keep repeating.

In case your stranded you can turn the starter a little bit by hand so the brushes are on a different spot on the armature, then try the key. Or try tapping the starter with a wood block.

[AaronM]

Thanks again for the reply, I appreciate it! I'll more than likely take it to the mechanic now, but at least I can know what's going on. Thanks again!