Home › Forum › Ask A Member › 40 hp Big twin Selectric gearbox questions
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frankr.
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April 16, 2017 at 5:46 pm #6760
I’ve just ended up with two of these, a ’63 and a ’65. I understand in a basic way how these work but have never touched one before and don’t quite know where to start.
How do I locate the leads to the coils?
Is it useful to check the resistance of the leads/coils? What should it be?
Is continuous power needed to keep the clutch springs wrapped, or do they stay on their own once triggered (or whatever one calls it) by the coils.
Can I check functioning in the shop by energizing the coils? How? Is there anything to watch out for as far as causing damage?
I have heard that with no power these default to forward gear. Is this so?
What are the chances of these gearboxes being usable? What usually goes wrong? I see that internal parts are available but not at prices that would justify major work…..
Maybe there is already a thread that answers these questions?
April 16, 2017 at 6:01 pm #562011. The leads come out of the exhaust housing through the hole where you would normally access the shift rod coupling. Then up along the backside of the exh housing (inside the lower cover) and clamp at the cylinder head. There are rubber sleeves covering the disconnects
2.Yes, you can check the resistance between each lead and ground. I’d have to get the book out to see what it is supposed to be (4 Ohms???)
3. Yes, continuous power is required to hold it in gear
4. Yes, you can apply 12V to each lead and ground. If running, clutch will engage and prop will turn. If on a stand, clutch will engage and lock the prop in one direction only. You will be able to turn prop in other direction with some drag felt.. WARNING–never apply power to both leads at the same time while running. Something will bust if you do.
5. WRONG. The Hydro=Electric shift defaults to forward. Yours defaults to neutral
6. They actually are pretty reliable. Killers are water in gearcase (rust) and poor electrical connections (rotted wires). Shift switches in the control are hard to get and $$$$
April 16, 2017 at 7:18 pm #56209quote FrankR:1. The leads come out of the exhaust housing through the hole where you would normally access the shift rod coupling. Then up along the backside of the exh housing (inside the lower cover) and clamp at the cylinder head. There are rubber sleeves covering the disconnectsThanks. Found them.
2.Yes, you can check the resistance between each lead and ground. I’d have to get the book out to see what it is supposed to be (4 Ohms???)
Measuring at the conector to the control box, I got 8 ohm in one and 10 in the other. Differences could easily be due to sketchy patch job on wiring.3. Yes, continuous power is required to hold it in gear
I guess this is why the electric shift units all seem to have had generators? Is there a minimum voltage needed to keep the box engaged? When it drops too low will there be damaging slippage or a clean release?
4. Yes, you can apply 12V to each lead and ground. If running, clutch will engage and prop will turn. If on a stand, clutch will engage and lock the prop in one direction only. You will be able to turn prop in other direction with some drag felt.. WARNING–never apply power to both leads at the same time while running. Something will bust if you do.
Yes, it behaves just like you say, in both directions. The free backwards movement feels like a spring clutch releasing.
5. WRONG. The Hydro=Electric shift defaults to forward. Yours defaults to neutral
6. They actually are pretty reliable. Killers are water in gearcase (rust) and poor electrical connections (rotted wires). Shift switches in the control are hard to get and $$$$
Initial impression: The quality of the electrical stuff is not up to what one needs for a critical circuit in a marine environment. Need tinned wire of larger gauge, higher quality insulation, plated connectors, get rid of the spade terminals, better switch ….. What I see looks marginal for fresh water, probably would not last at all in Florida….
Question: I don’t see any interlock to prevent shifting at open throttle. Am I missing something?
Has anybody come up with a good substitute for the factory switch? Looks like it just needs a single-pole-double-throw, ideally with a delay through center-off.
April 16, 2017 at 8:25 pm #56213The safety interlock in the control box is what makes the (not very waterproof) switch so expensive. I suspect Irgie Irgins had a hand in that. He always had a need to make things unnecessarily complicated. . . 😀
April 16, 2017 at 9:28 pm #56215The Evinrude push button control has a sliding lockout that prevents pushing the buttons at high throttle settings. Due to the way it is made, the condition just can’t exist in the Johnson control. In theirs, the throttle lever operates the shift switch before the throttle moves.
April 17, 2017 at 1:49 am #56224I noticed the prop has a solid hub–no rubber. Is this something special to the Selectric gearcase?
What are the specs on the "C" type gear lube? Is it equivalent to anything generic?
Thanks for all the guidance.
April 17, 2017 at 1:56 am #56226It is NOT a solid hub. You just can’t see the rubber, but it is in there. Unless of course it is some off-breed prop. OMC/BRP now calls their old Type C "Premium Blend Gearcase oil". Aftermarket/generic suppliers still call it Type C. Supposedly, you can use Dexron ATF in an emergency. I’ve never been that desperate.
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