Correct way to bench test starter for ’67 V-4 OMC?

[1-old-outboard]

Hello to all;

Trying to bench test my Prestolite MGD 4001 12V starter; which came off my ’67 V-4 80 hp OMC.

I hooked up jumper cables to a marine battery which shows 12.33 volts, (red to +, black to -), clamped the red cable to the positive lug on the starter, and then touched the black cable clamp to the one of the mounting bolts; nothing. Then to the case of the starter: nope.

I got zero movement of the gear.
Is there anything I’m doing wrong? Is there a better way to test this?!?!

The sad part is that it worked before I had it serviced. It sounded rough, so I took it to a local, reputable electric shop, which has been in business for many decades. They just did an auto starter for me, and it works beautifully.

I’ve done a dozen auto starter replacements, but zero marine starters. Removal and installation went well enough, and there are no, "extra" parts.

I made no other changes to the system, electrical or otherwise. The dash light comes on, and I can hear the solenoid click when I turn the key.

The battery is slated for replacement, (we only get about 5 years out of batteries around here, with summers often topping 110 F. But it’s lived inside the garage, and shows plenty of power on the multi-meter.)

All opinions welcome on this.
Many thanks!
Alan
Member AOMCI

[frankr]

If the cables are hooked up as you described, there is something wrong with that starter. Not even making a bunch of sparks, right? Make sure you have good cable connections at the battery. Otherwise the starter has to come apart to see why there is no continuity in there.

[1-old-outboard]

Many thanks!

I’ll take it back to my local shop, and go from there.

And, I’ll post the answer, if / when I get one.
Appreciated!

[legendre]

Couple things here.. first off, voltage alone isn’t a sure indication of battery power. Are you reading that 12.3V open-circuit, or when it’s connected to the starter during the test? If you connect a 12V car headlight, does it burn nice & bright for a few minutes without fading? Load-testing is the way to go.

Also, if the starter was +just+ serviced, it may be that the brushes aren’t properly seated yet. After verifying your battery condition is A-OK, try the test again, but give the starter case a good hard smack with a hunk of 2×4 or bang it on the benchtop and see if it takes off. You can also try rotating the armature a few degrees to a different segment / brush contact position (don’t do that when the battery is connected).

[jcrigan]

Sometimes jumper cables look good but will not carry the current to the load. Internal corrosion i guess.

[1-old-outboard]

Battery fail!

Hooray for that.

Hooked the starter up to a known good battery and it spun like a top.

Hooked it up to the old battery, with the multi-meter attached, and watched the voltage drop from 12.3 to a mere 0.77.
I’ll call that a fail!

Many, many thanks.
Alan

[legendre]

quote jcrigan:

Sometimes jumper cables look good but will not carry the current to the load. Internal corrosion i guess.

They typically go to crap where the wire is crimped to the clamp, and the clamps themselves are often of marginal quality even when new. Add the effects of corrosion and old, weak springs, and you’ve got something that looks like a pair of cables but might as well be air.

But a dead battery won’t work with the best of them..

[legendre]

quote Smokey:

Hooked it up to the old battery, with the multi-meter attached, and watched the voltage drop from 12.3 to a mere 0.77.

Isn’t it amazing how easily you can be fooled by surface charge / open-circuit voltage? You see this all the time when t-shooting electrical systems.. "The socket reads 12V but the dang bulb wont light?!" (look for the high-resistance connection or wire in the circuit.. it’s there, 100% guaranteed).

Anyway, you’ll not make that mistake again! Glad you were able to figure it out.

[Author]

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