1971 Evinrude 50hp shift wires

[JS4MSU]

I'm having wiring issues with my '71 50hp. I picked it up for free because it was binding when turning over. Of course no start. Upon inspection, it turned out to be a fried lower crank bearing. Powerhead rebuild is done. Engine starts, and runs great (in forward). I've read ALOT of posts about the voltage to the solenoids, and I understand that 12v green is nuetral, 12v both green & blue is reverse, and no power is forward. My problem is that the two wires coming up from the lower unit are not connected to anything at the powerhead terminals or harness, and they are black! Whoever did the troubleshooting prior to me, must have dropped the lower for inspection, and disconnected the wires. I've had the lower unit off (impeller replacement), and it's obvious that the wires have been spliced. They are encased in some type of redish silicone. That makes it hard to trace which wire is which. I tried your advice of energizing the wires from the starter solenoid to determine if they are working, and I think I can hear a faint clicking each time. I haven't tried that yet with the engine running. From the info I got about the engine, it was shifting with no problems before the powerhead failure. The lower unit lube appeared fine as well. My question is where do these two wires connect to in order to recieve their power signal? I'm a new member to this forum, just joined tonight.

 

[Joe Reeves]

Re: 1971 Evinrude 50hp shift wires

I assume that you know that you must use what is called "Premium Blend" gearlube, also known as "Type C", available at your dealership. You cannot use "HiVis" that is used in the mechanical shift engines.

You can achive the same effect as running to have that lower unit shift by simply removing the spark plugs and sranking the engine via the electric starter. Just be sure NOT to have that electric starter energized for more than 20 seconds at a time to prevent overheating.

The connecting wires would be near the rear portion of the powerhead on the starboard (right) side and should have what is called a knife connector on the end of each wire.

If no knife connector exists, look for two wires leading from the engine harness that are not connected to anything, then check the voltages when you engage the shift control/switch.

 

[jay_merrill]

Re: 1971 Evinrude 50hp shift wires

If the wires coming out of the exhaust housing both have black insulation, they are not the original wires. The stock part for this motor is a wire bundle that has one green wire and one blue wire. The portion that runs within the exhaust housing should be encased in a black rubber sheath. If you did not see this when you replaced the impeller, my suspicion is confirmed.

The reason why the midsection wires are encased in rubber, is because they are subjected to heat, soot and water. If the original part has been replaced, you most likely have just a pair of regular wires in the midsection. If so, this was done because the original part is an NLA item. While it is understandable that someone did what they had to do to keep the engine going, this is not going to be a very good solution in the long run.

The wires located in the cowl, which connect to the exhaust housing wires, will be green and blue. They should run directly out of the plug on the starboard side of the motor, around the back of the powerhead, to the location on the port side of the motor where the exhaust housing wires are located. If black wires have been spliced into this portion of the wiring, I would replace them with the correct colors.

The green wire is the neutral wire and the blue one is the reverse (along with the green) wire. Using the techniques previously explained, determine which of the midsection wires is the neutral wire, by noting which of them causes the motor to go into neutral when 12VDC is applied to it. Once you know that, put a piece of green "shrink tube" on it, or a piece of green electrical tape.

You may also wish to go to your local OMC/BRP dealer and buy the proper knife connectors for this application. Don't forget to get the black rubber boots that go with the connectors. If so, I would drop the gearcase again and get rid of the "silcone mess" that you apparently have there. I would also replace the black wires with green and blue wires. Try to wrap the new wires in something durable, as well.

I would be very careful about spending alot of money on this motor, until you have determined its overall health. The "jackleg" repairs that someone seems to have done to it in the past, would make me very nervous about the kind of maintenance that it received prior to your ownership. Start with a basic compression test and trying to figure out why the engine was "binding." The early 70s hydro-electric shift OMC motors can be good motors if they have been well maintained, but they can be a nightmare if not taken care of.

Proceed with caution!

 

[JS4MSU]

Re: 1971 Evinrude 50hp shift wires

Thanks for the help Joe and Jay. I cut back the electrical tape on the harness leading toward the powerhead and found the green and blue wires you referenced. The two black wires coming from the shift solenoids must have been yanked from their connections! That's why I couldn't "see" where they had been disconnected from. I started the motor with muffs on, and jumpered the wires to the starter solenoid in order to check function and determine which was nuetral and reverse. Yes! They work and it shifts. I then attached nuetral to green and reverse to blue with heat shrink splices. All is good. Motor is ready for the water tomorrow. BTW, yes I did use premium C lube. I definitely got that message from reading all the previous posts regarding this engine. Thanks again

 

[JS4MSU]

Re: 1971 Evinrude 50hp shift wires

"I picked it up for free because it was binding when turning over. Of course no start. Upon inspection, it turned out to be a fried lower crank bearing. Powerhead rebuild is done. Engine starts, and runs great (in forward)."

Thanks for the tips Jay....compression is 100 in each cylinder.

 

[jay_merrill]

Re: 1971 Evinrude 50hp shift wires

i'm not sure what the compressions should be in that motor. In the triples, it can be as high as about 150 psi, but that doesn't mean the numbers should be the same. Maybe Joe can chime in on this subject.

Still, I'm curious. When you say you did a rebuild, did you just replace the lower bearing? If you honed the cylinders and replaced rings along with that, I would expect to see more than 100 psi per cylinder.

Just curious.

 

[JS4MSU]

Re: 1971 Evinrude 50hp shift wires

You're right on that one, Jay. No work to the cylinders. I didn't notice any significant wear or damage to the cylinder walls, so I took a chance on saving some money. Everything else looked good when the crank bearings and seats were exposed. I cleaned & cleared the oil passages before installing the new bearing. I then replaced the lower crank bearing, gasket set, two carb rebuild kits, and the lower unit pump impeller. It's all good. Passed the water/fun test today. When I got it back home, I re-torqued the head for good measures. Thanks again for the help and interest.