Couple questions about a 1975 Evinrude 25 hp outboard

Hello fellow boaters, I have a couple questions if anyone can help me regarding a 1975 Evinrude 25 hp outboard motor w/ long shaft that I picked up today. The 1st question is how do I shorten the shaft from long to short? The extension part makes it to long for my 1448 starcraft seascamp v-hull. My transom is 16". The 2nd question is how do I jimmy rig a remote start set up without a key. The outboard has a female outlet for the remote starting assembly but that part is no longer available. It will pull start but I have a bad shoulder so not a good idea. I use the tiller to operate the throttle so as long as the setup is located around the back bench or on the motor would work for me. Let me know if you need more info. Thanks everyone

Long shaft to short shaft requires changing out three things:

1) Remove the housing extension
2) Replace the longer driveshaft (P/N 0315386) with a standard driveshaft (P/N 0315385)
3) Replace longer shift rod (P/N 0303257) with a standard shift rod (P/N 0303098)

To get your a remote start hooked up without using the original plug, you're going to have to splice into the original wires with a new plug or wires. It's hard to tell from your picture exactly how many of the small pins you have in the connector. Looking at the exploded view, I see five separate small wires and two large wires coming off of the harness. Of course the two large wires are your Pos and Neg to the battery.

Of the remaining 5, I would guess they lay out like this:

1) RED: +12V from the battery
2) Black: Gnd from battery
3) Yellow/red stripe: Starter wire which will activate the starter solenoid
4) Purple: Ignition wire which will kill the motor when grounded.
5) Purple/white stripe: Electric Choke solenoid

So to simply start the motor, you will need to connect the two large wires to the Pos/Neg of the battery. Then you will need to wire a momentary switch between the red and yellow/red stripe wires (a 12V 5A switch would be fine). This will engage the starter for as long as you push the button. Just be careful, as I don't see a neutral safety switch on this, so it will start the motor, even in gear.

If you are careful and neat, I would think it would be pretty easy to mount the push button right on the motor housing, meaning less wires running around your boat. And since you need to operate the choke and throttle on the motor anyway, a remote switch won't help much. You will need to use the existing kill switch to stop the motor.

Good luck!

Looks like there might be a discrepancy on the purple wire and black with yellow stripe wire. Don't know for sure although this chart is pretty good as far as my motor is concerned. You will figure it out. Kofkorn submitted a good post.
Tim

[url=https://forum.tinboats.net/viewtopic.php?p=366885#p366885 said:

earl60446 » Yesterday, 15:30[/url]"] Looks like there might be a discrepancy on the purple wire and black with yellow stripe wire.

Click to expand...

You're right, my bad. The purple wire would be the switched +12V from the ignition switch. If you ground this wire, it'll end up popping a fuse. Black w/Yellow stripe will ground out the magneto and stop the motor.

Good luck!

Thanks for all your help guys. The button on the side of the motor ended up being a starter switch. The guy I bought the outboard from said it was a kill switch. So thats one thing tooken care of. Today im going to drop the lower unit to see if it has extensions on the parts or what I need to order to make it a short shaft. I took the motor out for a spin yesterday and while I was going full throttle after 10 minutes it would sound like the motor was going out of gear reving real loud. I lowered my speed and it would go back in to gear. It did this to me a few times and then I couldn't start the motor up again and had to get towed back to the dock by the local sheriffs. I have no clue where to start diagnose this problem. Any ideas any one? The last owner said it replace everything and he never had a problem with it. What a pain in the butt this is turning out to be.

Revving while moving is only a limited few things:

1) Spun hub on your prop. - Scratch a mark across the inside of the hub that goes from the aluminum of the inner prop across to the nut that retains the assembly, Take it out for a spin and get it to rev again. Once out of the water, check to make sure the marks line up. A spun hub will usually only let you move forward just at or above idle before letting go. If the hub is spun, you'll need to send the prop out to have it re-hubbed.

2) Shift dogs are wearing out - The lower unit uses very coarse cogs that align when you shift. You need to do a sure and quick shift to clunk the dogs in place without grinding them. If you are hesitant and hear a rattle when you shift, you are shifting too slow. A quick way to see if the dogs are skipping is to hold the shifter with a bit of pressure while running the engine speed up. If it doesn't rev while doing this, your shift dogs will likely need to be replaced. This is not a simple DIY job, and you may need to find a shop with tools to do it.

3) Splines on the drive shaft have sheared - not a very common problem. When you drop the lower unit, inspect the splines for damage. If damaged, replace the driveshaft (you'll need to do this anyway to convert to short shaft)

4) Poor adjustment for shift linkage - Make sure that your shifter is securely engaging with a good feel to it. usually much more of a problem with remote shift/throttle. There really isn't any adjustment for linkage on a tiller.

One concerning statement that you made is that you've run this thing on the water for 10 minutes, yet you haven't dropped the lower unit yet?? These motors are EXTREMELY reliant on a proper cooling system, and the impeller in the lower unit is the most critical part. You should always inspect/replace this on a newly purchased motor, as you have no idea of the history of part. It is too critical to the functionality of the motor. I hope that you are seeing good flow of water out of the rear exhaust ports, I don't think the '75's had any tell tale yet.

My fear is that after running for 10 min, that you could have cooked the motor if the impeller was old or damaged. That could explain why it isn't starting after running for a while. If you have a compression tester, run a check on your cylinders. You want to be over 100 psi, although it will run with 80. You want both cylinders to be within 10% of each other.

If compression is ok, then it's time to start looking at the spark. But we can approach that after clearing the compression.

Good luck!