67 evinrude fastwin powerhead serial

[Saintnowhere]

have a 1967 evinrude Fastwin 18hp the powerhead has been replaced and is white so that tells me it came
from a johnson, but 'm not sure if its a 18 or 20hp all i have is the welch plug serial #12535436. also i noticed the
fuel pump plate has been swapped to use the standard fuel pump so it must be an older powerhead. any info would be great.
thank you

 

[RCO]

The 18 and 20 powerheads were identical in the years where both were produced. Evinrude was an 18 and Johnson was 20. There weren't many changes from when they put on a thermostat (1961?) up to when OMC went to the low tension ignition in 73.

 

[Saintnowhere]

So what was the difference? carb or cylinder head or were they both really 18 or 20hp?

 

[F_R]

I think it was the carburetor but not really sure. What I do know is that it made very little difference. Probably not even enough to notice. Call it Marketing.