Lower unit conversion

[Seahorse50]

Ok I have a 64 starflight 90hp evinrude with the electric shift.
My issue is the electric shift don't work and I have a manual shift 59 johnson seahorse 50 hp and I'm wondering if it's possible to swap the lower units? They look like they may match up bolt wise. Just wondering if it would match internally?

 

[racerone]

Have you done any testing on the electric shift.---Electric shift is very good and reliable.-----Apply 12 volts to the green wire and see if you can spin the prop one way and not the other way.----Repeat with blue for reverse.

 

[boobie]

I'd do some trouble shooting on the electric shift to find out exactly what's wrong with it.

 

[Seahorse50]

I've tried 12v to the blue and the green wire.. It spins free both directions. However when started it slowly creeps forward like it's barely catching maybe? But cannot shift at all and more throttle don't seem to move it any faster.

 

[jimmbo]

Ok I have a 64 starflight 90hp evinrude with the electric shift.
My issue is the electric shift don't work and I have a manual shift 59 johnson seahorse 50 hp and I'm wondering if it's possible to swap the lower units? They look like they may match up bolt wise. Just wondering if it would match internally?

The bolt pattern is about the only thing that would match up. the 90hp has no provision for the mechanical shift linkage the 50hp lower unit would need.

Do a resistance test on the circuits. One ohm meter lead attached to ground, the other to the blue wire. 8 ohms is what you're looking for. Repeat with the green wire. Do you have the correct oil in the gear case? Premium Blend by BRP or Type C oil is the only type of oil for that system.

 

[Seahorse50]

Oil I don't know as I just bought it, I do know that when running it leaks out a black oil from just above the impeller.

 

[jimmbo]

There are two large flat blade screws on the gear case. Bottom one is the drain/fill, the upper one is a vent. remove the screws and drain whatever is in there. Refill from the bottom until oil comes out the top. Use BRP Precision Blend, or a Type C oil if using other brands. You said some black oil comes out above the impeller? I don't recall our 1965 having a drain hole above the impeller. I hope you are not running it dry, as in, no water being supplied to the water pump? If so, it guarantees you will be pulling the gearcase off to replace the water pump. Something you should do anyway as you just got this engine

 

[Seahorse50]

Dry run no, but when in the water I get a rainbow color in the water. And after pulling out of the water it continues to drip. I'm assuming this would be a bad lower seal on the engine?

Also smokes a lot but also has not been ran much in sometime.

So low oil could be my cause of it not shifting? Wondering if I understand this correctly?

 

[boobie]

Make sure and check those ohms and get back to us.

 

[racerone]

Motor will still shift with low oil level in the gearcase.

 

[Seahorse50]

Ok I got a ohm tester and when I test either blue or green the ohm meter jumps from 4 to diffrent numbers until it hits 18 then goes back to 1.. My ohm meter shows 1 to start with not really sure why but it does.

 

[racerone]

If the 90 hp runs good then take that powerhead and swap it onto the 50 hp midsection.

 

[Seahorse50]

Ok so I've got the 90hp bolted onto the mid section. Well doing so I noticed a switch on the side of the distributor that is triggered pending where the throttle is. It has only one wire, I'm thinking it should have a ground running from it as well?
Or am I mistaken?

 

[F_R]

You are mistaken. There are two tabs on the switch, but only one is used. The switch body itself is the ground. That is the safety switch that prevents starting the motor at high throttle settngs.

Have you checked to see if the hood will fit over that 90 powerhead? Just thinking and wondering.

 

[Seahorse50]

Hood did not fit, I had to use the plates and hood from the 90hp. Witch created a issue of not having a place for the shift lever. But after a few trips to the hardware store and some drilling. I was able to get that connected (Rigged). Also have to move the steering cable forward as the 90hp is a lil bigger and don't line up.