1972 Evinrude 50hp electric shift question.

Hi All,
Just bought this motor as a replacement for a very tired 35 hp Chrysler and being on a budget, this is what I came up with.
I have a question about the shift solenoids. What ohm reading should I get when connecting green wire and blue wire to ground?
I am getting 3.8 ohms on both.
Reason I'm asking is because I cant select neutral when running, only forward and reverse.
I am in the process of changing the oil in the lower case, drained it today, and it was BLACK!!! New Type C oil is coming tomorrow.
Should I flush the gearcase with something first, I mean the stuff that was in it was really, really burnt.

Any help will be very much appreciated.
Craig

djcraig said:

I have a question about the shift solenoids. What ohm reading should I get when connecting green wire and blue wire to ground? I am getting 3.8 ohms on both. I cant select neutral when running, only forward and reverse. I am changing the oil in the lower case and it was BLACK! New Type C oil is coming tomorrow.

Click to expand...

Craig.... In the past, OMC did on occasion have whale sperm lubricant added to the gearcase oil, and this is what causes the very black coloring (not a joke). It really stinks too doesn't it?

(Hydro Electric Shift System Explained)
(J. Reeves)

NOTE 1 -The ohm reading of the individual shift solenoids should be between 5 to 6 ohms. The ohm meter should be set to low ohms. The shift wires leading to the solenoids must be disconnected when being tested.

NOTE 2 - The solenoid plunger measurement must be made with the solenoid placed within the lower unit. The measurement must be approximately 1/64" beneath the top surface of the solenoid... NOT above the solenoid surface nor any lower than 1/64" of the solenoid surface. This factory measurement is critical and will not ever change UNLESS someone has tinkered with it.

The shifting setup of the lower unit is what's called a "Hydro Electric Shift", which is quite complex consisting of voltage being applied to solenoids in the lower unit which in turn change oil passages via a oil pump that supplies various pressure on a spring loaded shifter dog. The wires leading to the lower unit (at the powerhead) are "Green" and "Blue". The engine must be running or cranking over in order to shift out of forward gear.

You CAN NOT use HI VIS lube in that lower unit. You MUST USE what OMC calls "Premium Blend" lube, commonly called "Type C". (A thinner lube)

Note: The engine must be running OR have the driveshaft turning by some other means in order for the engine to shift.

In neutral, you need 12v to the "Green" wire.
In reverse, you need 12v to both wires, the "Green" one and the "Blue" one.
In forward, there should be no voltage to either wire. (The spring loaded shifter dog forces the unit into forward gear)

To check the lower unit for proper shifting to make sure you have no trouble there, remove the spark plugs to avoid problems and to allow a higher cranking speed.

This next step eliminates the actual shift switch in case problems may exist there.... Disconnect the blue & green wires at the knife connectors (the rubber insulated boots) leading to the lower unit at the powerhead, then using jumpers, take voltage direct from the starter solenoid to apply voltage to the "Green" wire for neutral, then both wires 'Green" & "Blue" for reverse (Remember the engine must be cranking over in order to shift).

With no voltage applied, the unit should be in forward. No need for a ground jumper... the lower unit's already grounded. You may crank the engine with the key switch or by energizing the starter solenoid with a jumper wire.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1

A good Hydro-Electric unit can be shifted by turning the driveshaft by hand.--Special socket and ratchet wrench.-------Does not need to turn at a high RPM.

How far are the pistons inside the solenoids supposed to move when powered up?

That information is already posted for you in post #3.-------They do not move very much when motor is not running, if that is what you are looking for when putting 12 volts to them !

Ok, here is the story so far.......
Have just had the solenoids down to the marine mechanic to check, I thought the reading I was getting was too good to be true so I got him to double check, and, Both register 6 ohms.
Got him to check continuity all the way from solenoids to knife connecters, all good. Got the switch checked, it is doing what it is supposed to do, no power with forward pressed, power to green when neutral pressed, and power to blue and green when reverse pressed.
SO....
With it all reassembled, with new impeller for good measure, and with brand new OMC premium blend oil in it, sparkplugs removed, and cranking over quite fast with the starter, and guess what?????
Still no neutral....... I have forward when forward is pressed, and reverse when both neutral and reverse are pressed, but no neutral.

So once again, any ideas?
Thanks guys

Very simple gearbox.--------Do not force anything.-------First step is to remove the solenoids.----May be as simple as a broken lever on the control valves.

Note that, with the engine out of the water, and either actually running or simply being cranked over as fast as possible with the electric starter, the propeller will no doubt rotate when the shift switch is in neutral... simply because of internal friction within the gearcase. This friction is cancelled out when sumerged in water due to the water's back pressure action upon the propeller.

Have you attempted to stop the propeller from rotating with a piece of wood or some such object?

If you're absolutely sure that when in neutral, the propeller is truly rotating in a reverse direction... disconnect the "Blue" shift wire at the knife connector that leads to the lower unit. Now, if the Problem disappears and you finally have neutral................

Either your mechanic is in error and the neutral position of the shift switch is actually providing voltage to that "blue" wire... OR............

The charging system of the engine is somehow throwing voltage to that "blue" wire BUT ONLY when the shift switch is in neutral... very unlikely and I don't see how that could be possible... OR...............

The solenoid(s) are not adjusted properly which can be, and usually is, a first class pain in the a$$ as each solenoid must be inserted individually in the lower unit in order to check that the plunger of each is below the top surface of the solenoid BUT no lower than 1/64 of an inch below.

The above is assuming that all components have been assembled with the solenoids within the lower unit such as the white plastic/nylon spacer washer between the solenoids and the wave washer on top of the upper solenoid.

Ok guys, finally tracked down the problem!
There is a short somewhere in the wiring harness between the top knife connectors and where it attaches to the solenoids, I guess green wire was supplying power to blue wire at all times when either neutral or reverse was selected.
So, my next question is, and only asking because the original harness is both hard to find and way too expensive for me right now, can I manufacture a harness myself from some high temperature wiring, ie like they use in electric ovens etc?
It doesn't seem like it would be too difficult making up 2 wires in a heat proof caseing or am I missing something?
Any tips will be greatfully accepted.
Thanks again,
Craig

Ok Guys, an update for you.
Today we had our maiden voyage, and all was good for the first 2 hours, a combination of slow cruising and flat out running.
As we made our way back, we were about 500 metres from the ramp, I thought i'd give it one last squirt for the day, when something weird happened.
Boat started to take off, then engine just started to rev out, so throttled down straight away, and it kept going forward as normal, tried throttle up again and same thing, engine reved but with no more speed.
It felt like maybe the prop has let go of the hub, and while it is under just above idle it is still gripping but anything over that and it slips.

So got it back and got it home, and with all the trouble i've had with the gearbox, I decided to drain the gearcase to see what the oil looked like.
I found it a bit discoloured and did look like it may have a tiny bit of water in it.
Could this cause the slippage mentioned? Doesn't seem likely but I thought i'd ask you guys as you do certainly know way more than me when it comes to these things.
I will source a new gasket for the solenoid cover tomorrow and also a new grommet for where the water pump connects to the pipe, didn't put a new one in when I did the impeller.
And the gasket was hard to find for solenoid cover but will order and wait for it this time.
I will do the centre punch thing on the prop and hub to see if it is that is the problem, but like I said, I thoughti'd ask you guys again for your valuable advice.
Hope to hear from you guys soon.
Cheers
Craig

Make the gasket !----Try another prop.---------I would install a seal kit and it does include that gasket.-------------Maintenance does not cost anything , it saves a bundle of money.

Is it hard to put a new seal where the propshaft is?