If you have the carb model that came with that motor (pictured), I would remove all non-metal parts and soak top and bottom in lacquer thinner overnight, then follow cleaning instructions above. A dedicated carb cleaning kit might be a good investment (eg...
Repurposing a timing light to check spark is an old trick (gives you a way of checking spark while driving the boat). No flash, no spark. You still must measure spark, though, if you have it. Use an adjustable open air testing device (cheap) -- testing ignition strength. Another useful trick...
hope so. learned a new use for a timing light anyway.
always considered electric fuel pumps extremely dangerous on outboards. Maybe technology changed.
As previously suggested, replace the electric pump with a standard pulse pump, probably from an earlier model of similar hp. The VRO pump by itself works fine with premix and the oiler disconnected, but it sounds like there may have been problems with the VRO pump. Get clear about which pump...
10s from the mid-50s to mid-60s were powerful motors. I'm not very familiar with the 9.5, but know the 10 will take the 7 1/2 (same year, condition, same boat) hands down, and will troll down nearly the same.
Ethanol (as in E10) doesn't bond with with water like methanol does (eg. in dri-gas). So if you had a water problem, and drained tank, lines, carbs, addition of dry-gas isn't a bad idea to make sure the water goes away.
I burn E10 in my old truck if running it regularly -- outboards or my...
^^agree. Use a deep cycle battery with a lot of storage capacity. Supplement charging with a trickle charger at your home (if trailered) or at the dock if slipped. You should have not problem -- go to a two-battery system if you run a bunch of hungry electronics.
Think I would check compression again and record the findings for future reference. IMO, 150F is on the high side, measured at the top of the head. If salt water use, you may have some partial blockages in the water passages. I agree that it could be a problem with the power pack (or perhaps...
Assembly guide and decal set. I would strip it down, sand, prime and paint: https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1971&hp=50&model=50172S&manufacturer=Evinrude§ion=Motor+Cover
The portable fuel tank has to be vented. Might try operating with the cover loosened or removed. Also -- sometimes helps to raise the tank up to the level of the powerhead or a little above.
