Evinrude yachtwin 4hp long shaft cooling question

[Pete and repeat]

Hello all. I have this ol' outboard I'm trying to fix. It's not really broken, though. When I got it it was seized. I pulled the plugs and soaked the cylinders in some oil for a while. I eventually freed it up...probably from sitting so long it froze up, I got it running and it ran pretty smooth and sounded good. i only ran it for maybe 20 to 30 seconds at a time. I wanted to see and hear it run, but knew I was probably gonna have to change impeller. Pulled the lower unit off and got to the impeller...2 screws holding cover pain to get off. But impeller looked good and flexible. Anyway, let me mention I did pull upper housing originally when I was trying to see if it was shaft and gears frozen or the motor. When I did that. I noticed the water tube running down, the motor end threaded and the lower unit end with a 45 degree cut end. When I pulled lower unit/impeller inspection, I didn't see the tube. It wasn't going into what I'm assuming it was supposed to be going into, which was the inlet on the impeller housing...hole about the size of the copper tubing that was topside. In fact, the water tube I am guessing is about a foot short of the lower unit. My first guess was that, being this is a long shaft, which was probably an extension kit on original shorter shaft, that either the water is supposed to fill up in extension and finally reach the water tube at the 45 degree end, Which makes completely no sense. Lol. Or that the history of this motor was that someone added the extension kit to make it a long shaft and never made the water tube longer to accommodate the longer shaft? Or somewhere down the road motor was serviced and not put back together correctly? But then I think if that was the case it probably would have overheated or seized motor. But like I said , motor runs good. Can anyone tell me the proper functioning of the cooling system on these motors? Should I find some copper tubing and extend the tube down to the impeller housing? That is the only thing that makes sense to me. I'll try to get some pics tomorrow to add. It looks like a clean outboard with low use. But when I did run it I didn't see any water pissing out like your typical outboard. So for fear of doing damage I stopped playing with it and came here to ask. Any help appreciated ( :

 

[oldboat1]

Welcome! Interesting first post.

The long tube is probably not to be found, so extending the one you have may be the best solution to get up and running. An extension is typically 5", 10" for an extra long shaft (not sure if there was a 4hp extra long yachtwin). If you can determine exactly what you need, it's possible to find a matching piece of copper tubing and splice it in place with a piece of fuel hose around the water tube.

What is the model number of your Yachtwin?

 

[Pete and repeat]

Hey. Thanks for the advice. That's what I did. I got lucky and found some copper tubing I had as scrap that was same size. Flared it and was able to reuse fitting. Hardest part was making sure to cut it right length. Now I can feel a little safer when running it, knowing it's at least all hooked up right. So after seeing the internal workings, I blew some air into tube to see where water comes out after it runs through motor. It looks like it just shoots out into housing and extension. Is this right? and then finds its way out through the little holes? So, basically, where should I be looking to see where the spent water is coming out to know its working properly ?
By the way, tag only shows serial number, which is 4236 s e0003518. I'll try to add some pics once I figure out how. lol. or add attachments. It keeps saying I am not authorized to create or edit attachments, whatever that means. Thanks again for the help.

 

[oldboat1]

That would be a '72 model number. The location of the small holes varies a little by year, but should get a light spray if it's pumping, with most exiting out through the housing as you describe. Run it in a barrel with the water level about half way up the leg, with the cover off. Check temp on the top of the head.

Should run around 120-140F, but not over 160. If it's too hot to touch, it's too hot.

[Edit. BTW -- see there was a 15" extension for the 4hp in '72!]