Evinrude ID mixed 25hp or 18 hp

[dfgtye]

Hello everyone. I just picked up an older Evinrude looks good but will need some TLC, plugs ,points new lower unit oil etc. The cowel cover says Evinrude 25 and looks like the color scheme of a 1971. The model number plate reads 18602C-E13799. I know this is a 18 hp 1966 number. The previous owner did not know much about it. They aquired it used about 5 yrs ago. I want to make sure I get the right parts when ordering. I can tell work was done on the powerhead ( paint is cleaned off and gaskets are newer ) I suppose its possible that someone put a 25 hp power head on a 18 hp base. Is there any way that i can ID the power head . The numbers on the engine plug are 385440 RPH. Thanks for the help.

 

[Chinewalker]

Re: Evinrude ID mixed 25hp or 18 hp

RPH designates that as a replacement powerhead. Got any pics of the motor, cowling on and off? The '66 would have the space-ship inspired cowling design dating back to 1961, while the '71 would be the boxier design kept into the 1990s. Also, the '66 would have the "small" carburetor, while a 71 (both 18 and 25) would have the big bore carb.

Unless you're rebuilding the motor and seeking pistons or a crankshaft, most all service parts are the same for any of the 18s, 20s and 25s of that era. Same carb kits, same waterpumps, same fuel pumps, same ignition components, etc.

 

[dfgtye]

Re: Evinrude ID mixed 25hp or 18 hp

The motor looks like a 71. Has the square cover. Any way to ID this as a 18 or 25. How do I visually tell the difference between the small and big bore carb. Any idea of the bore diameter of either? I'm not too concerned about the lower end since that is definitively a 18602 I can order parts. The power head is were I want to make sure the points, plugs and carb kit is right. Is there anything visually different between the 66 18hp and a 71 25 up other than the box cover

 

[Chinewalker]

Re: Evinrude ID mixed 25hp or 18 hp

Yes the '71 (both 18 and 25) will have a carb that looks like this:


While the '66 will look like this:


I am guessing that if you have the '71 cowling style, then you likely have the first carb, as the choke & adjustment linkages, etc. don't line up easily for coming through the belly pan.

Is the paint on the clamp bracket with the serial tag the same as the paint on the rest of the leg? Not uncommon for broken parts to be swapped around...

 

[dfgtye]

Re: Evinrude ID mixed 25hp or 18 hp

It's the 71 carb. No doubt. The paint looks the same on everything. I tried to load a pic but keep getting an error. Pretty sure now it's not a 1966. I'm thinking that it is more likely a 70s 25hp. Started trouble shooting tonight. No spark. Pulled the flywheel points look like new no corrosion. Gave a quick rub with a file in case there is any film. Will check for shorts tomorrow. Thanks for the help.

 

[brasmnky1]

Re: Evinrude ID mixed 25hp or 18 hp

RPH designates that as a replacement powerhead. Got any pics of the motor, cowling on and off? The '66 would have the space-ship inspired cowling design dating back to 1961, while the '71 would be the boxier design kept into the 1990s. Also, the '66 would have the "small" carburetor, while a 71 (both 18 and 25) would have the big bore carb.

Unless you're rebuilding the motor and seeking pistons or a crankshaft, most all service parts are the same for any of the 18s, 20s and 25s of that era. Same carb kits, same waterpumps, same fuel pumps, same ignition components, etc.

I too have an evinrude with 385440 RPH on it. I was told it was a 15 HP and interchangable with a 20HP. It is on a saildrive from the 70's or 80's, not as an outboard. I am looking for a 20HP replacement so as to use it in a 24 ' sailboat. But, when I compared it to a mid 1990's evinrude 20HP, the 20HP was bigger and longer and wiuld not bolt to the mounting plate. For what should I be looking to find a bolt-up replacement?

Thanx, Bob.

 

[kfa4303]

Re: Evinrude ID mixed 25hp or 18 hp

Hi bras. Welcome to iboats. Here is a great all around link for these vintage 18/20hp OMC motors. I have a '66 20hp Johnson myself.

Maintaining Johnson E & FD Serie
How to Decode the Model Number on a Johnson Outboard Motor | eHow

 

[1946Zephyr]

Re: Evinrude ID mixed 25hp or 18 hp

On the rear portion of the powerhead, you should find a quarter sized welch plug. That should have the model and serial number stamped into it.