Starter swap - Chrysler 75 hp

7lazy77 · Jul 25, 2011

I just replaced the starter in a 1973 engine with a rebuilt starter from a 1969 Chrysler 75 HP motor. It was my understanding that the parts were interchangable. When I go to start the motor, it appears that the index doesnt fully extend to the teeth of the fly wheel. I am far from being a mechanic & was trying to figure out what the problem is. Any suggestions?

fucawi · Jul 26, 2011

Re: Starter swap - Chrysler 75 hp

should be 1/8 in clearance between the flywheel and starter pinion ..ie has to move up 1/8 before contacting the flywheel ..have you checked this...

7lazy77 · Jul 26, 2011

Re: Starter swap - Chrysler 75 hp

fucawi,
I will have to get a pic & post it tomorrow so you can see how it looks. Thanks

7lazy77 · Jul 26, 2011

Re: Starter swap - Chrysler 75 hp

Went out & got a couple of pics tonight & measured the distance between the top of the starter pinion & bottom of fly wheel, which measured 1/8" on the nose, so not quite sure if my problem lies elsewhere. My marine battery was completely dead, so I pulled the battery out of my old Farmall A mowing tractor (which is much smaller) to use. Could this be the possible problem & why the starter pinion isn't fully extending & engauging in the flywheel to start the motor????

fucawi · Jul 26, 2011

Re: Starter swap - Chrysler 75 hp

once it actually gets into the flywheel teeth the pinion is driven upwards by the load ....a good battery and thick cables are essential for reliable operation

7lazy77 · Jul 27, 2011

Re: Starter swap - Chrysler 75 hp

So with the smaller battery that I am using, I may be just lacking that extra "load" to push the pinion the rest of the way into the flywheel. I will have to get another bigger battery to try. I am sure the cc amps vary quite a bit, which may be my problem.

fucawi · Jul 27, 2011

Re: Starter swap - Chrysler 75 hp

The cables I am using are 80 Sq mm rated for 550 A you need to go for 50 sq mm cables minimum

7lazy77 · Jul 31, 2011

Re: Starter swap - Chrysler 75 hp

Well, I got a new battery & tried starting motor again. Did the SAME thing (top of pinion made contact with bottom of flywheel & just spun below it without going into the flywheel teeth). Don't think it is my cables, since it was working fine before I had the starter rebuilt. Soooooo, I am at a lost & don't know where to go from here or what to try next??

fucawi · Aug 1, 2011

Re: Starter swap - Chrysler 75 hp

If its just spinning and not moving up then either its stuck with rust or gunge ..so clean it in parafin ...is it running the right way ..it could have been built by accident to run the wrong way you only need to fit the brush plate wrong by 180 deg ..it should run anti clockwise...or the pinion sleeve threads are for a clockwise motor ..if they have been changed .......turn the pinion clockwise by hand and it should go up if the sleeve is right ,

Sorry your original posts did not make it clear it sat below the flywheel spinning

7lazy77 · Aug 1, 2011

Re: Starter swap - Chrysler 75 hp

Pinion turns clockwise & goes up. Any other suggestions? Might have to take the boat & motor in to the place where I had the starter rebuilt. Thanks

Frank Acampora · Aug 1, 2011

Re: Starter swap - Chrysler 75 hp

Ahh! Check again. Looking from the top, flywheel should turn clockwise and starter motor, bendix, and pinion should turn counter clockwise.

fucawi · Aug 1, 2011

Re: Starter swap - Chrysler 75 hp

frank and I are getting to the nub of the problem ..it seems your motor is running the wrong way ..check that at let us know clock or anti clock ???

7lazy77 · Aug 1, 2011

Re: Starter swap - Chrysler 75 hp

Thanks fellers, I will check them tonight. Just out of curiosity, "IF" the starter/bendix is going clockwise.....is it really that easy to mistake the direction when it was getting rebuilt/cleaned?? It seems that this would be something that would be hard to mix-up on a rebuild, but what do I know (did I mention that I am NOT very mechanically-inclined).
As previously stated, I swapped starters & rebuilt one. Do both motors (1969 & 1973) rotate the same (flywheel -> clockwise & starter/bendix -> counter-clockwise)???
Thanks again!

Frank Acampora · Aug 1, 2011

Re: Starter swap - Chrysler 75 hp

Both starter motors rotate the same direction. I really would not expect the bendix to rise at all if the motor was turning in the wrong direction because the helix (spiral) inside the gear that throws it up would be turning the wrong way.

Stranger things have happened though

Y'know: I just remembered---Some of those bendix assemblies have rubber bushings inside of them. If the rubber wears out, the gear will not rise all the way. Check to see that the bendix itself is working properly. Remove the motor and then remove the bendix. If it rattles, it is bad. If the bottom is pushed up into the case it is bad.

7lazy77 · Aug 1, 2011

Re: Starter swap - Chrysler 75 hp

Checked starter on motor, & bindix rotates clockwise in upward motion. This would mean that the flywheel rotates counterclockwise. Looked at old worn starter that I took off & it rotates th exact same as the rebuilt one that is on motor now. What am I missing here? I am really lost at this point!

fucawi · Aug 2, 2011

Re: Starter swap - Chrysler 75 hp

rotating the pinion with your finger is the opposite to the shaft rotating inside it ..so lets go again

pinion to flywheel clearance vertically 3 mm 1/8 check
pinion will wind up into flywheel by hand mesh with the flywheel ..its not too tight into the teeth ..by nature this is a sloppy mesh .... check
Motor rotates in the correct direction anti clockwise looking from top check
Inertia drive mechanism ( often refered to incorrectly as the bendix) is not rusted or gooed up ..check...

Well it should work fine

final point ...with the motor off the engine or flyweel removed operating the starter should cause the pinion to fly to the engaged position and then get pushed back by the anti rattle spring ...if it does that its fine .....does the teeth count on the new pinion match the old one eg 10 teeth ..

Its a real problem this because if I could see it in the flesh the problem would be easy to solve...

7lazy77 · Aug 3, 2011

Re: Starter swap - Chrysler 75 hp

UPDATE: So I was visiting with the shop that rebuilt the starter & they informed me that the starter was fine & to possible look at the the source of power by beginning with "jumping" the motor with some jumper cables. Hooked it up to a vehicle, grounded it & when I touched the the positive to the starter, it fully engaged the bendix with teh teeth on the flywheel & began to crrank the motor!
So....this now leads me to several other questions. The old battery (that is no good anymore) that was previously used on the boat was a 27 group battery with 750 cranking amps. The spare battery that I have (& what I was using as a backup) is only a 24 group battery with 650 cranking amps. Can the 100 cranking amp difference be causing the problem that I am having, or could it be in the wiring?? Do the older outboard motors require more cranking amps than newer outboards?? Thanks

Starter swap - Chrysler 75 hp

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