Evinrude 25 Electric Conversion

[LaqueRatt]

Picked up a Johnson donor motor today. Want to put the starter and all the related bits onto my Rude. They are about the same year, but more different than I thought they'd be. The Rude is a 77, the Johnny a 78 (I think). Both have a power pack. Has anyone here tried this before? Can I just bolt up the starter and keep the pull start too? Flywheels the same?

I know the starter and solenoid will need to be installed, but not sure what else. Attaching some pics. Don't know what to do with the plug inside with the ghetto wiring and what is the canister that looks like a solenoid to the lower left of the carb for?

 

[LaqueRatt]

Guess I'm on my own with this one. That's OK, I'll suss it out. Just figured this was a common upgrade.

 

[matt167]

Fairly common. Parts between 2 back to back years should swap. As long as they are in the same generation. The last generation of 20-35hp came in 1977 if I recall. 1976 would be different

 

[Scott Danforth]

time to look at the parts breakdowns

 

[LaqueRatt]

Anyone care to put me on the right path here by answering my questions? Sure would make my life easier!

 

[racerone]

I think looking at the parts manuals found on line , you can help yourself.-----I often post answers that are deemed suspect by novices.----Sorry to be blunt here.

 

[F_R]

Fact is, those two motors are very different. You are contemplating taking parts from one motor and putting them on a different motor. Ain't going to happen. You might be able to cobble something up but that is what you will get. Sorry.

 

[Willyclay]

time to look at the parts breakdowns

The website at the link below is a good way to compare parts. Good luck!

1977 Evinrude 25702H 25 hp Outboard Motor Parts

Lookup Evinrude 25702H 1977 25 hp parts by boat engine section and buy discount parts from our large online inventory.

www.marineengine.com

 

[jimmbo]

In 1977, the 25hp was a 22 cubic in. block, in 78 it switched to a 32 in. block. As F R said very different.

 

[racerone]

????---in 77 the parts book shows a 32 inch block for the 25 HP.-----There may be some 22 cube engines in 77.-----Only with more pictures can we tell what you have here.

 

[LaqueRatt]

I agree, need to do a bit more research and look at some parts diagrams. I'm fairly certain though that these two engines are "basically" identical. The change occurred in 77 and from what I gather OMC stayed with it for a few years. Spent an hour or so comparing the two side by side and the only real difference seems to be that the electric start motor has quite a bit of extra stuff to make it work. Has a whole bunch more wiring and it's all messed up in the Johnson so I'm a bit clueless what hooks up to what. Anybody have a wiring diagram by any chance?

Was a bit surprised to see the carbs have diff part nos, even though they look the same. Only real diff is the rude has a screw for adjusting low speed jet and the johnny has a knob. Think I'll go with the knob if it fits.

The air box silencer bolted right up and that's the part I really needed. Looks like the starter/solenoid/bracket will bolt right up too. The mounting holes for it are there. I'm just hoping the teeth on the two flywheels are the same so that I can retain the pull starter. Did OMC ever make a 25 that had both?

 

[racerone]

The 40 HP models in the 1960's had both.

 

[F_R]

Well I'll be darned, Time to eat some crow here. The '77 was indeed the 32 cu block. Knowing that, the starter just might work on it. The main difference I see is the Johnson is what they called a "Remote Electric".

Carburetors are different in that the electric start model has an electric choke.

Time to dig in and see what can be changed over. I'm thinking it is a "Go".

 

[jimmbo]

Well I'll be darned, Time to eat some crow here. The '77 was indeed the 32 cu block. Knowing that, the starter just might work on it. The main difference I see is the Johnson is what they called a "Remote Electric".

Carburetors are different in that the electric start model has an electric choke.

Time to dig in and see what can be changed over. I'm thinking it is a "Go".

The Feathers are stuck between my teeth too!

 

[F_R]

I'd like to help here, but I'm too darned sick. But it would help us all to know what the OP's goal is. Just adding a starter motor with a push button start on the cowl, of a remotely operated one with start and choke switches up front as the Johnson is?

 

[racerone]

I am not sure what the OP has in mind either.----Seems he picks up motors at yard sales / garage sales / buy and sell.

 

[LaqueRatt]

Yep you're pretty much correct R1. As usual. Just something to putter around with. Goal is to use this one on my only current boat, the Mirro. Since it's a real "beach" to pull on, I want to convert it to electric. Seems like I could get away with simply running power from the batt to the solenoid and hooking up some kind of switch to trigger it. I'd rather it not be all ghetto though.

As for the choke on the Johnny, I *think* it may have a manual AND electric. It has a normal choke for sure, but there's a solenoid attached to the carb that must do something. I just don't know what.

 

[brodmann]

next to the carb is a choke solenoid. I'd get a momentary switch (only works when pressed in) and wire it to the battery and the solenoid. I'd do the same with the automatic choke if you want to use that, or just remove it. Also, there's the whole battery charging system. There should be a rectifier on the donor motor that probably connects to the starter solenoid to return power back to the battery. If you check to see where all the wires go on that 6 prong plug, you'll probably be able to figure out all the wires that were used for the battery/key switch/charging system and electric choke. The rectifier for charging the battery is pretty small and insignificant looking, but should stand out as a part that's on the donor, but not the one you plan to use. You'll want to keep that or else you'll have to charge the battery constantly. That'll be a nice feature if you can figure it out. I think you'll find it to be pretty easy once you jump in and get started. Looks like the only real obstacle is your hesitation in getting started.
Go for it! You've got this, and we're here to help. We can handle specific questions once you get started.

 

[stresspoint]

years ago i swapped the parts to make a pull start 25 to electric start , i swapped the harness , flywheel , stator , just about everything aside from the carbs and engine block, i remember it wasn't as simple as i thought .
unlike you are doing , i went to a remote shift as well
from memory , even the lower cowl was different to allow cabling to go through.

 

[LaqueRatt]

Thanks for all the help and encouragement. I pretty much take my time with everything. Even though have done a fair amount of wrenching, I'd never claim to be a mechanic. Much better at taking stuff apart than putting it back together. I was wondering if the motor was capable of charging the battery. What does the rectifier look like? Is it an alum block with fins like in old TV sets or is it solid state, sorta like a chip or a resistor?