Hey guys,

So on my Mariner Magnum III, occasionally when I go to crank her up I'll have 1-2 random times where the starter will just spin, not engaging the engine at all.

I'll just hear the whirr of the bendix going.

Been having this problem for a while, but usually 1-2 cranks will get me back on the flywheel.

I decided to take off the cowl yesterday in preparation for going to Lavon tomorrow, and I went over the bendix with some WD-40 a few times, moved it around by hand, but noticed that I could not get it to go all the way up and engage the flywheel by hand. Is this normal?

As in, I could move the small gear of the bendix up to the flywheel, but the teeth were not aligned to let me go into the flywheel for engagement.

Tonight I will probably do the same thing with the WD-40, also clean up all of my battery terminals before I start charging everything up as I heard that could have some impact on the starters effectiveness.

Any thoughts are appreciated!

Missing teeth on flywheel? Solenoid?

starter motor could be getting weak, if the bendix was cost effective, i would go ahead and clean the armature shaft with crocus clothe and replace the bendix

I think the flyweel is in great shape, the 1/2 of it I saw yesterday seemed pretty solid. Going to check around it today and see what it looks like.

Will take a look at the solenoid connections today too. I think all of my batteries need their terminals cleaned tonight so I'll clean them all up and see if it helps.



If I get all my connection endpoints clean and that little bit of WD40 doesn't help me out here, I will most likely see about replacing the bendix, depending on the price of the entire starter unit I suppose I might just try and get my hands on another starter altogether.

Part of me wants to try replacing the solenoid first before cracking the entire starter outta there... solenoids aren't too expensive I don't think, I've heard they get burnt out / weaker over time

If the starter spins when key is engaged the solenoid is good. Starter brushes weak and worn bushings will cause the starter to run slower. The starter bendix can become worn and not engage correctly. You can get a complete new starter for under 100.00 bucks. eBay item number:231334261179

don't buy a cheap rebuilt one. Get a new Arco, at least. Piece of mind

I've seen this caused by bad battery connections. Just not enough juice to engage it all the way.

This is where I would start troubleshooting. you should have two meters and a friend to test. Keep one meter on the battery, and another connected to the terminal on the starter. Hit the starter and get both readings. you don't want to see a voltage drop over 1volt between the two readings. anymore than that says that the connection between the battery and the starter has issues when under the load of the starter.

you should have around 12.5 to 12.8 volts measured on the battery after it has been charged, then left overnight for the top charge to bleed off.

make sure all measurements (taken above)at the battery are taken at the actual post that comes out of the battery, not at the clamps that attach to the post. you could have a bad/corroded/dirty clamp/connection that will give you invalid readings.

once you have confirmed that the electrical system is providing the proper voltage under cranking conditions, then look at the starter and bendix. As stated by Fisherdad58 low voltage at the starter will not allow it to spin up fast enough to 'throw" the bendix into the flywheel and engage it....... it will just spin.

Another trick I have used is to manually pull the bendix up into the starter by hand, and rotate the flywheel just a bit by hand so that the bendix fully engages the flywheel. If it stays put, then you can put your meter on the starter terminal, and take a reading when you crank the engine over. it should not drop below 10.8 to 11.2 volts under cranking. if it's below that, then your not getting enough juice to the starter....... causes could be weak battery, bad/dirty cables, bad solonoid (internal contacts still working, but damaged enough to not pass full current to the starter, or a burned/shored/dirty communtator inside the starter. comparing the voltage at various points along the circuit path (from the battery to the starter) while simultaneously reading voltage at the battery will help isolate where the problem is (if voltage drop under load is over 1Volt between the battery and starter)

Keep us posted.

You need a new starter, plain and simple.

usually weak bendix if battery and cables are good......

Checking back in after this weekend, after having cleaned my terminals and connection endpoints, I got a bit more reliability out of it. Very happy with that, the whole day I only triggered the spinning sound just once!

(Where previously it was one spin per attempt at starting)

The interesting part was the only time I did trigger the spinning, it was on a crank where the motor was turning for a second, then it reverted to spinning the starter after about a second.

So the flywheel was engaged for a bit, but somehow the starter let go?

Either way in that instance I just trimmed down a bit more to level out the carbs a bit and vrooom, got her going again on the next crank.

So I am pretty happy at this point. The connections getting cleaned seemed to have do me some good. If I start getting a bunch of spinning starts now I will just go ahead and replace the thing

You should replace it....before you tear up the teeth on the flywheel. Each time that starter slips onto or off of the flywheel teeth, unrepairable damage is being done to a very expensive part.

Sounds like you need a driver retainer kit. It includes the spring. Also known as a bendix as others have written. I would check the condition of the battery and connections first and if it is over 4 replace

Got it, I will most likely just replace the starter. My boat will be out of commission during the winter here and that gives me all the time to do the needful maintenance and repairs to it that I want to do.

I'll just put this on the list!

I don't think your starter is bad bud. I'm betting you need to replace your battery cables. Try a new positive cable and I bet that fixes the problem. I had to do that on my boat after the same thing you described happened to me.