2007 Mercury 115 4 Stroke Starting Issue

[-Marc V-]

I picked up a new rig and bought it with a known starting issue. I was thinking it'd just need a new starter but I popped the starter off it yesterday and connected it directly to a battery and it works fine. The solenoid pops the piston deal up and it spins just fine too.

Put it back on the boat and when I turn the key the same issue as before is happening where sometimes on the first, second or third key turns it just clicks. I'm assuming the click is the solenoid popping up the gear piston deal but no spin. When I was looking at the boat before I bought it the starter would sometimes not pop up the solenoid then a key turn later would but the gear wouldn't turn the fly wheel, then the next key turn or two it would work fine.

Could something else be the problem like the ignition switch or something? And any suggestions on how to troubleshoot? I think the battery is good. Had the battery charged and it's only a few years old.

Thanks in advance!

Marc

[marine_man]

When you tested the starter off the motor.. were you testing it with the starting battery or another battery you had laying around?

When you put it back on the motor, can you see what's happening? Is the pinion gear spinning up & contacting the flywheel, but it doesn't have enough power to turn the motor over?

marine_man

[-Marc V-]

I was using a different battery. In hindsight now wish I would have used the same.

When I watched it a couple weeks ago it just seemed that the solenoid was pushing the pinion gear up, sometimes after a couple key turns just to get the solenoid up, and the starter wasn't even trying to spin the pinion. But a key turn or two later would turn the motor over fine.

[marine_man]

It almost sounds to me like the starter or solenoid has a "bad" spot in it... where it can't generate the torque needed to spin the motor over, but can freely spin it when no load is applied.. I'd double check that with your starting battery (that it spins over freely) when it's not bolted to the motor first to rule that out...

You could also rule out the harness / etc by jumping the starter directly (vs going through the harness, but I'd be surprised if it's there, typically the harness / key switch is off / on, and the amperage on / off happens at the starter.

marine_man

[-Marc V-]

It's not hard to take the starter off, even for a guy like me, but could I just swap in the battery I used to test it with off with the starter on ( since it's already back on) to see if it works then too?

I'm a wanna be mechanic with some simple skills so hoping that would work. Guess it wouldn't test the starter when it's not on a load, but just thought it might be a little easier to switch the batteries.

[marine_man]

Yep, that'll work fine.

marine_man

[Ufatz]

Are we CERTAIN the battery is "good" or do we just think it is good. And I second the problem being in the starter motor someplace. A batt that is slowly going to hell will produce intermittent "juice"-sometimes hot....sometimes not.

I'll be watching to see how it is resolved.

[-Marc V-]

The battery is from 2012, and a higher end blue optima battery it looks like. Might not mean much if it wasn't taken care, but was hooked up to an on-board charger.

Regardless that's why I wanted to try the battery I tested the starter when it was off the motor because I know that one works. I'll check the current starting battery too. I have a chance to play with it more tonight so will keep you posted.

One thing that kind of sticks in my head is the previous owner said he had an issue with his first battery not starting it right I believe, so he up'd the battery size/amperage and said it's worked fine till now. I sometimes overcomplicate things, but could the alternator in the motor be slowly killing batteries if the battery I got it with is now bad after 3 years? Just a thought.

[Drail1313]

I had a issue just like that a few years back. Did the same trouble shot, starter, solenoids, battery.

Turned out to be the Positive wire from the battery to the motor, it was all messed up inside the casing!!! (chemical reaction of copper and air will break down over time.) Might be worth a try.

Good Luck!!!

[-Marc V-]

I'm kind of baffled. My dad helped tonight, and watched a voltage meter at the starter while turning the key. The voltage at the starter he said was fine. It just clicked, or only engage the solenoid, without spinning the pinion only a couple times tonight. The greater majority of the times turning the key tonight it spun and started to turn it over like it should. Maybe it just needs to be used more often?

Not sure what to do. If voltage is fine it's not the battery. Or the wire. Which sounds really odd to me, but maybe that happens more often than I know of. If it's worth just replacing the starter and being done with or not...

[marine_man]

Personally, at this point, I'd be inclined to take your starter to a starter rebuild business, or get a new one.

marine_man

[Drail1313]

Remember that the voltage is only a reading of DC amount, the real power is in the AMPS. (as with my problem I did the same thing!! Voltage was never the problem with mine, AMPS BABY!!! AMPS!!!)

[delcecchi]

If the voltage is correct while the device operates, and the device is not defective, the amps will be correct. If the battery cannot supply the needed current the voltage will drop.

Remember voltage=current x resistance. or current = voltage/resistance.

[Ufatz]

I think I come down on the side of Marine Man. Take the %$^ # starting motor to somebody for a rebuilt or just replace it.

But it IS a puzzler.

[-Marc V-]

Are rebuilds worth it? Or just better off getting a new one? Looks like they run a little over $300 for a new one for this model merc.

[marine_man]

In my experience, rebuilds have performed just as well as the original for a whole lot less...

marine_man

[-Marc V-]

Cool, I'll look around to have it rebuilt to see what i find. Thanks a million Marine Man and others. Appreciate it.