starter question

[badfish888]

ive searched and just wanted to try and confirm something, its a starter on a 2002 mercury 125 saltwater. i was out the other day, trolling on and off, and when trying to pick up and leave i went to start the boat and the bendix just spun, it would not engage the flywheel. i tryed a few times with the key, volt meter read almost 13 volts. so i popped off the cowling and gave it a tap with a pair of pliers, then tried again and it worked. for 2 days some times it would work, sometimes it wouldnt. My dad said the solenoid mite be goin bad, and like an old truck ude only get a few taps before it stops completey. i tries taking off all connections and throwing the battery on the charger for the night for the hell of it. put every thing back together, and took it out. 5-10, starts throughout the day with out a problem. how would the connections allow the bendix to spin, but not engage, and y did tapping it help before?

 

[sschefer]

Re: starter question

Your dad might have bee right. The solenoid is nothing but an electro magnetic swicth that lets you use a much lower current to close the switch than it takes to turn the starter. If it weren't for that solenoid you would need much larger wire to your key switch. A good connection is required at both side of the solenoid. On the low current side you still need a solid and steady curent to hold the switch closed or the connection can become intermittent. Eventually that will cause carbon to form on the internal contacts and you will not be sending the amount of current you need to the starter. The starter will spin up slowly and not create the force required to thow out the bendix and allow it to engage the teeth on the flywheel.

Not withstanding, the grease on the starter motor shaft can become contamintated with dirt over time and that will also keep it from sliding smoothy and extending out far enough to engage the flywheel. I've replaced a lot of bendix assemblys on starters as part of a routine starter rebuild. Most of the time they didn't need replacing but the new ones came in the kit so why not. What I'm saying there is that they don't really fail all that often, it's usually the solenoid or starter brushes that go.

 

[hotrod53]

Re: starter question

If putting a few drops of 30W oil on the shaft doesn't fix it, take it apart and look it over. There isn't much in a starter, I just had mine apart on my Merc 50. You may have worn out brushes, or like mine, maybe the bushings were dry and needed lubed. You will have to make a tool out of sheetmetal to hold the brushed in place while you reassemble it, 5 minutes and a pair of tin snips and you'll have your tool.

13 volts at the battery may not mean anything, its about current delivery, but I would also check all connections. Every time I see this question come up, the first suggestion is to check or change your battery.

 

[JB]

Re: starter question

You probably fixed the trouble when you cleaned up the battery cable connections and charged the battery, badfish. It only takes a tiny bit of hidden corrosion in those connectors to limit the current to the starter motor to less than needed.

That is why over half of the solenoids and starter motors that get changed weren't broke, they were just starved of enough current.