Big Twin Starter Motor

[nj-boatbuilder57]

I’m a little confused about what’s going on here….

Are you looking for a starter motor frame? I have one from a 35HP Gale, just like the one in the eBay link in the post above…and you can have it if you need it. But it holds a 3" diameter motor (which is what these engines take).

Or, are you looking for a frame that holds a smaller diameter motor? I’m not sure that exists. I can’t say for absolute certain, but if you got a 2-1/2" motor, I suspect you got the wrong one. I’ve never seen anything but 3" diameter motors on engines of this size / age.

FWIW, I bought a 3" motor on eBay for $52….works great.

Anyway, if you need a 3" bracket, here’s what I have. I don’t know if the motor is any good or not, but you can have it, too, if you want. The gasket is shot, so you’ll need to get a new one.

[outboard315]

By the way if you are concerned about a used starter you could rebuild it. All that goes bad are brushes, bearings and a good cleaning.

[nj-boatbuilder57]

Well, the insulation on the windings can break down, too. These days, the copper wires are coated with modern, high-temp polymers, but back in the ’50s they were wound with a simple enamel or even just a baked varnish. If you intend to refurb an old motor, at least be sure to megger it first to make sure you’re not wasting your time…

Personally, I wouldn’t bother with a motor that’s this old since a suitable replacement will cost about 50 bucks….

[boscovius]

Well, life has certainly found a way to interfere with my best laid plans. Haven’t really touched the boat for the last 3 years. Had to get some emergency electrical work done and had to move the two lower units I had been rebuilding in order to clear out a workspace for the electrician. I hadn’t been able to figure out how to get the spaghetti seals to stay in place long enough to get the clamshell in place and bolted on. After the electrician was gone I got a bug up my rear to go back at it. I had been advised by someone else on this forum to use a 3M aircraft gasket sealing material for those lower units and that’s what I did. They are now sealed up and next on the list is to send my two best propellers in to get new hubs installed and straighten the dinks out of the blades. New starter is on it’s way, hopefully after all this time I’ll be able to figure out how to put it back on. So appreciative of all the help on this forum. Couldn’t have gotten as far as I have without you guys. Goal for this summer is to get it running in a test tank and try to get a new floor and transom in the boat itself.
The wife is thrilled. Lol.

[need2fish]

Should you new starter not fit, consider having the old rebuilt (as long as it spins freely and the pin gear hasn’t been eaten.). Some time ago I found a shop that rewound mine for $100.

[boscovius]

Thank you. I will consider that. The gear is in great shape actually.

[boscovius]

Haven’t updated this post in a while. Got sidetracked with life and other projects. I’m thinking I could probably just have this starter rebuilt. I don’t think it really needs much. New brushes and a good cleaning of course. I think the spring in the bendix is worn out, or at least it’s just dirty because the gear doesn’t want to slide back down the shaft easily. Now to find a reputable place around here that will do it for a reasonable price. Thanks for all the tips. I can say that I have completely rebuilt the two lower units I have for this engine and I just got the reconditioned propellers back last weekend. Still a long way to go but hopefully I’ll have her back in the water before my kids are all grown up.

[boscovius]

Ok, Duh. I hope someone is still paying attention to this thread because I think I’ve stumbled upon the most important clue. Cast into the aluminum of the starter mounting bracket of my OMC 25028, Serial Number 21715, Big Twin 35 is the part number 203572. It doesn’t show up in ME’s records, but I’m hoping one of you all can help me determine a correct replacement for that starter motor. Knowing the bracket it bolts to ought to be half the battle.

• This reply was modified 2 years, 11 months ago by boscovius.

[Mumbles]

203572 is the P/N for a ’56 and earlier six volt starter bracket. I’m pretty sure 203944 is the P/N for 57 – 58 Big Twin twelve volt starter brackets.

[boscovius]

Thanks Mumbles. So if I understand this correctly, I could either stick with the bracket I have and have this old 6 volt starter rebuilt, or I could swap out the bracket and install a 12 volt starter. I’m told the Arco 5376 should bolt up to the Big Twin bracket. But obviously not the Big Twin Bracket I have. Can’t believe I never thought to look for a part number on that bracket until now. Thanks for you help!

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