I just got a 1980 model 64HOF. Probably very similar to yours although I cannot find your model number listed at boats.net. Mine has the old style WIKO/Prestolite points and condensor ignition that was used for years; simple enough. I would check that on the one you are looking at; ignition parts for the solid state models are very pricey by comparison.
These are the loopers; I have been told that they are great running motors; I am looking forward to running mine once I get a few issues resolved.
Mine takes the impeller #F525065-1….which sells for an astounding $125.00 from Mercury. Forget that; chrysleroutboarddude found that the OMC #0436137 is a direct fit and costs less than $20.00. I just installed it in mine; I simply shortened the drive pin a bit and it’s working great. Mercury should be ashamed to feel the neeed to charge so much for a necessary service part; fortunately there is an alternative.
They are basic motors; not even a thermostat. As with most all Chrysler derivatives…..they are a glorious example of very simple engineering and design. I think I’m going to like mine.
.
