1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

ollyfarren

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May 21, 2010
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5
Hey all,
I have a 1971 Evinrude Lark 50hp.
I got it with a boat I bought, the guy who sold it to me told me that the engine was scrap! as he could never get it to start.
I could not get the engine running either but i noticed that it had excellent compression so I decided to try again.
I got the old service manual for it and went through the wiring diagram. I noticed that one of the Posative terminals from the starter solenoid was connected to the engine (grounded), I put it onto the starter solenoid and the electrics on the engine came to life!

I changed the plugs, lines, gear oil(I used standard gear oil), checked impeller etc.... hooked her up to a battery and she started up first turn!

The only problem I had was that the engine was stuck in forward gear, I checked the shift solenoids in the gearbox and noticed that the connections were submersed in gear oil, so I put new connectors on the wires and covered them in oil-proof tape. I put the whole thing back together using a small gasket that I made from gasket paper (was thicker than original gasket).

Started her up but still no shifting. checked the shift wires and noticed that the green wire was not getting any power because it was disconnected at the connecter beside the starter solenoid (wire had worn off the connecter) I reconnected the green wire and started her up....

NOW she was still in forward, i tried neutral and still nothing, BUT when I tried the reverse button the prop snapped into reverse. I tried neutral again and she snapped back into forward gear. (Why the F**K would she not go into neutral??)

I asked a few guys and they told me to get the correct type C oil for the Gearbox. After a long time and a lot of bother and money, I got 2 litres of the stuff that a dealer had laying around for the past 20-30 years.

I changed the oil in the Gear Case to the OMC Premium blend. I started up the engine, and...... It was still stuck in forward gear. I tried neutral but still nothing. i tried reverse and instead of snapping into reverse, it stopped for about a second and then started spinning a bit in reverse, then stopped for a bit then started spinning slowly then stopped again then started spinning again and kept doing this.... I then put her into neutral and the F***ing thing went into forward gear again! HOLY F**K, I am seriously frustrated at this point!

I checked to see if there was enough oil in the Gearcase and there was.

I tried the voltage going to the shift wires and the green wire was reading 9.4v when in neutral, the blue was reading 11.2v and green reading 9.4v when in reverse. ( also if i leave the key switched on for a while with the neutral button pressed in the green wire heats up!)
I tried taking a 12v jumper wire from the battery directly to the green wire, when I read the wire before i connect it it reads 12v, when I connect it to the green wire it reads 9.4v like before.
when I connect the green and blue to 12v jumper wires, the blue reads 11.2v like before.

Can anyone help me?????? I dont know what to do next???
 

F_R

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Jul 7, 2006
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28,195
Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

Green wire is neutral gear. It is shorted to ground or the neutral solenoid is shorted to ground. Green makes it go in neutral, BOTH blue and green together make reverse.

BTW, being submersed in oil is not the problem. That is the way they are made.
 

ollyfarren

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May 21, 2010
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Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

Thank you F_R.
is there any way to check the solenoids to see if they are ok - they certainly looked ok to the eye and the small wires coming from them looked normal (but then again, i am no expert).
When I open it up again, I will take a few images of the parts and post them here.
do u think using the thicker gasket on the solenoid cover would of made any difference? (maybe 1mm)




Green wire is neutral gear. It is shorted to ground or the neutral solenoid is shorted to ground. Green makes it go in neutral, BOTH blue and green together make reverse.

BTW, being submersed in oil is not the problem. That is the way they are made.
 

eavega

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Apr 29, 2008
Messages
1,377
Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

Your green wire circuit is shorting out somewhere. You should be seeing close to 12v on the green wire. I believe there is a check of the solenoids in the repair manual that gives you the expected resistance on the solenoid, which should indicate if you have a short on the wire or in the solenoid itself. I definitely remember there is more than just a voltage test for the solenoids in the manual. Unfortunately I don't own that motor (or the manual) any more.


Rgds
 

ollyfarren

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May 21, 2010
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Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

thank you eavega,
I will get the solenoids and wiring checked out first chance i get to open her up again.

pitty i couldnt replace this gearbox with a manual(non-electric-shift) one!




Your green wire circuit is shorting out somewhere. You should be seeing close to 12v on the green wire. I believe there is a check of the solenoids in the repair manual that gives you the expected resistance on the solenoid, which should indicate if you have a short on the wire or in the solenoid itself. I definitely remember there is more than just a voltage test for the solenoids in the manual. Unfortunately I don't own that motor (or the manual) any more.


Rgds
 

boobie

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Nov 5, 2009
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20,826
Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

Just picked up your PM so I'll answer here. Each solenoid should have 5-6 ohms resistance. Compare both wires to each other.
 

ollyfarren

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May 21, 2010
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Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

Ok.
Removed the solenoids from the Gearcase and did the tests. all checked out fine.
I checked the service manual to see if everything was ok.....
I noticed on a diagram that it showed the solenoids in a different order to the way they were in my Gearcase.
I tried to rearrange mine with the other one on top but the rod housing was too thisk for the top solenoid.
So... i put it all back together and swapped the green wire to the blue solenoid and the blue wire to the green solenoid.
re-attached the Gearcase to the Leg and fired her up........
YEEEEEEEEHHHHHHAAAAAAA!
the engine was in Neutral! I tried forward and it works. tried neutral again and yes it goes into neutral!
I tried reverse.......... it started spinning a little then stopped then started again, i put a bit of a rev on the engine and it started spinning a little.
Does anyone know what could be wrong?????
forward is no problem and neutral is no problem now but why could reverse be acting like this???





Just picked up your PM so I'll answer here. Each solenoid should have 5-6 ohms resistance. Compare both wires to each other.
 

will62

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Nov 25, 2011
Messages
103
Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

As others have said, sounds like your green wire is shorting out somewhere. When you swapped the green and blue wires, your problem went from no neutral, to no reverse. Have to find the short in the green wire. Try the amp draw test described in the pic below.

button shift.jpg
 

boobie

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Nov 5, 2009
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20,826
Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

Agree with above. Also the wrong oil or the plunger in the oil pump could be sticking.
 

F_R

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Jul 7, 2006
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28,195
Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

As I see it, you have a thick gasket (MIGHT be a problem). You are fooling around with swapping solenoids, the voltages are screwed up, the conditionof the piston in the oil pump is unknown, the conditon of the shift switch is unkonwn, and matters are just getting worse as you mess with it.

Bottom line: It is becoming difficult, if not impossible anybody to diagnose it from a distance. Our guessing isn't helping anything either. You need to back off and troubleshoot each system individually.

That lower unit can be bench tested by applying battery voltage to the wires and spinning the drive shaft (water pump removed to make it easier). Once you prove the gearcase is ok, you can tackle the external electrical system.
 

ollyfarren

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May 21, 2010
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Re: 1971 Evinrude 50hp Lark Electric Shift Gearbox Problem.

Thanks F_R.
I know a guy with an old 60hp Evinrude. It has a manual Gearcase. He thinks It will fit my engine.
Have u ever heard of this being done before?
(Conversion from Electronic shifting Gearcase to Manual Gearcase on 1971 Evinrude Lark 50hp)
He is not charging much for it.
 

Mike8087

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Jan 1, 2019
Messages
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I have a 1972 Evinrude 50hp the Electric Shift Gearbox.Can i Take a lower unit case from another 50 hp thats standard shift and use it on my electric shift gears and parts and do away with my electric shift 50 hp 1972 model? I wont to know if I can take the gears out of my electric gear case and put them in a manual shift gear case housing and will they work. I have a 50 hp loweunit case and the shift rod is here.
 

racerone

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Dec 28, 2013
Messages
36,265
I doubt you can make that work.-----Note , the electric shift have a bad reputation.----But in my opinion they are very simple / reliable / well engineered.----Best start a new thread because this one is old and will go " boom "
 

Joe Reeves

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Feb 24, 2002
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Racer... Yep, seven years old, so it's best to start BOOM!... Oh, Damn! :)
 
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