Grafting a newer motor on an older Evinrude outboard.

[n8kfe]

Folks
I have an older (1957) Lightwin that has had bad things done to the motor, no oil extended runtime. I would like to like to graft a ‘newer’ 1983 4.5hp Evinrude motor into the outboard. While the overall powerhead dimensions will allow it to fit in the original cowl including the old fuel tank the bottom mount is very different. First has anyone done something like this? Developing an adapter for the mounting and the driveshaft is doable their’s no sense in reinventing the wheel if it’s been done. Secondly is there a reference in identification of the additional ports are on the bottom of the newer block? So are obvious, like a water passage but others are not.

Basically I’m looking for any assistance in pointing me in the correct direction.

Thanks
Greg

[fleetwin]

Greg, anything is possible, but this grafting is near impossible. The powerhead won’t line up with the midsection of the old engine, the splines are different, and the water tube won’t line up either….

[n8kfe]

That’s what I was afraid of. It may make more sense to find a different powerhead. Do you know if the mounting bolt pattern changed on the 4hp when they went to the all roller/ball bearing crank?
Just looking to open up my options for repowering.

[reivertom]

Save yourself a lot of grief and find a used power head. There are a bunch of these motors from the 50s and early 60s so they come up for sale from time to time.

[fleetwin]

Just want to be sure I understand your objective here….I’m thinking you want to use a newer 4hp powerhead, but somehow adapt the older style side covers, recoil and fuel tank….Do I have it right? If so, it seems as though some of the newer 3/4hp models had this type of arrangement only with newer recoil and plastic lower cover….
So, I am thinking what if you used a newer style powerhead and midsection, say from a 79-early 80s model, then used the older mounts/rings/flywheel/mag plate set up on it….I don’t think you could use the ones with the neutral only gearshift set up cuz the shift handle wouldn’t fit under/over the aluminum side cover. But, these newer models had the two threaded holes in the block for the tank mounting ring, and perhaps the older front ring mount would bolt up to the front of the newer crankcases….
Just might work, will probably take some minor engineering changes, but seems like an interesting project….Don

[n8kfe]

Don

What I’m after is to use a newer ‘block’ on an old motor. I have figured out the simple parts. The old flywheel fits the shaft, this allows the old starter to be used. I’ll convert the ignition to a electronic style, the it appears that the needed bosses are all there they just need to be drilled and tapped. Either replace the original drive shaft, with one that fits the the crankshaft and splice it to the original drive spline on the bottom or depending on the mounting plate thickness have an adapter machined for the top. Then all I’ll need to do is to figure out the water tube and exhaust. O’ and the carb/choke along with the throttle. and the external fuel tank using the pump. just simple stuff. LOL

My intent is to have a motor that looks like a 1957 Lightwin with 4+ horsepower.
Just call me a hot rodder.

[jeff-register]

Purest!! ;>)!!

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