M440 Starter Bendix Drive.

My starter motor Bendix Drive does not engage with flywheel ring gear. When I turn engine keyswitch to start, starter motor turns but Bendix does not throw out to engage flywheel.

Could this be caused by weak battery? I plan to put 2 new batteries in this week based on age, but current batteries are on shore power charger and show charge ready.

My manual does not get into mechanical troubleshooting of starter Bendix. Yes, battery cables are tight.

I pulled starter and took apart to clean forward section of shaft where Bendix should ride when in engagment thinking that residual surface rust may be hanging it up. Same result when put back together. Entire internal parts of starter are clean and shiney as if new. It has never been under water and worked fine last time out on 06/06 when fishing with many starts thoughout the day.

Suggestions? New batteries go in Thursday. Also, manual does not make recomendation of battery size for M440. Any suggestions?

Thanks, Noel.

That might be it. If not, lube the shaft and work the Bendix a few dozen times and try again.

Jeff

My sons diesel Mercedes had the same problem so I took it out and dipped the nose/bendix end in Mobil 1 and it works great. Bench test it with jumper cables and you can se the bendix extend.

Dan

Just a thought. I know an engaged bendix does make a sound when it is thrown out. Have you heard the bendix engage ? Could be some teeth missing on the ring gear ! The suggestion of bench testing is a good idea. The old saying " Watch the Polarity " .. Hope it is only the bendix not engaging !

coaster said:

Just a thought. I know an engaged bendix does make a sound when it is thrown out. Have you heard the bendix engage ? Could be some teeth missing on the ring gear ! The suggestion of bench testing is a good idea. The old saying " Watch the Polarity " .. Hope it is only the bendix not engaging !

Click to expand...

No it has not engaged. I was unable to bench (deck) test last time because I didn't have cables and did not plan on this problem. I'm not ruling out ring gear but it is unlikely (fingers crossed). I'll find out for sure when I go back down there Thursday, with 2 new 675 CCA group 31 batteries. I did grease shaft at nose after I polished it with emory clothe.

In Australia , Valvoline make a product called " Tectyl ". I would expect something similar, is sold in the USA. I use it on my starter motor. Salt water environment. Do some research. While you are on the floor playing with the starter, you would apply Canola Oil,using a rag, arround the sump right up to the bolt heads. Will help deter rust and hence a hole in the sump. Something worse to do, than removing the fly wheel.

It was definitely the Bendix drive. After a test I took it back apart to determine why it was not throwing out. There is a retaining cir-clip, about 1 1/4" dia. under the nose which keeps the nose gear on the shaft. After removing it I was able to polish shaft further to the area that is under nose gear when it is at rest. Then reassembly with ample marine grease, a quick test with jumper cables on the deck and in she went. Its good to hear that M440 thumping along again!

I think that I'll add pulling starter every other year for a little cleaning, inpection, and grease to my routine. That is a very hostile environment for a piece of equipment that is so heavily relied upon. 1/2 hour of work would save a lot of headaches, and provide more piece of mind out on the water.

Thanks for all the input. ,Noel.

Good work!

Jeff

Noel, you are another wise and learned man. Prevention reduces failure. I have spares for practically everything. Nothing like having a spare starter motor sitting on the shelf. High and dry. To be rotated annually. I do that, even with my stern drive leg.

The Bendix drive system is pretty much old school these days.
These rely on a certain amount of quick armature torque in order to push the Bendix into the flywheel ring gear.
They don't like a low battery scenario, either!
These also incorporate a "sprague" clutch that can fail.
Any motor that looks like this is going to be Non-Gear Reduction, and will use the Bendix drive.


If this issue persists, I'd recommend replacing this old technology with a later HTGR/PMGR solenoid style starter motor.
(HT= High Torque.... PM= Permanent Magnet.... GR= Gear Reduction)
The HTGR/PMGR alone is worth the change over, IMO.

Not sure of which style your I/B's require, but the HTGR/PMGR solenoid style starter motors may look something like these:

..........

No Bendix principle is used.... only soleniod lever pinion action.
These will kick A$$ over the OEM straight thru/non-gear reduction style motors.

I can certainly appriciate the benefits to the gear reduction starter motor. Is there a direct replacment for the M440? What price should I expect to pay?

BTW, what internal parts differentiate a RH starter from a LH starter?

Thanks for the tip.

,Noel.

Noel, you'd have to contact a supplier to answer these questions for you.
There will be a LH Std Rotation engine starter motor, and a RH REV Rotation engine starter motor available.

If these M440 starter motors install into the flywheel cover from AFT of the flywheel side, then it gets a bit tricky to keep it in your mind, as the actual starter armature rotation is oposite of an Engine Mounted starter motor.

Again, this is where your supplier can help you.

As a rough example...... a Std LH rotation engine flywheel will turn CCW when viewed correctly from the flywheel end.

Your starter drive, if viewed from AFT, would rotate CW.



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Rick,

Yea, i understand that the single screw CCW turning engine in my 23' Classic Mako has starter turning CW. But since I have a spare engine, thus spare starter that turns oposite direction, is it conceivable that I could disassemble spare starter and re-assemble turning stator 180 deg to make motor turn reverse? The questions are, is Bendix spring wound in specific starter direction, are serations on Bendix clutch direction dependent? Basically, can an M440 starter be converted from one direction to other?

These 35 year old M440 starters are not normally in stock items these days.

Thanks.

Yes... the Bendix drive is directional as well.
This has to do with the spiral spline cut, the pinion gear "lead-in" point angle, and the sprague clutch....... otherwise, it would not work in either scenario.

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