Re: johnson 3hp what year
The 50:1 mixture I think almost certainly makes it post 1964 and 3hp is listed up to 1968. J4J are the listed plugs for that age.
There are 3 hp listed from 1989 and during the 1990s but the plugs recommended were QL77JC4.
On that basis my guess is 1964,5,6,7 or 8.
You might find a model number stamped on a core plug on the power head but dont hold your breath.
Take another look at the ID plate with a magnifier. You might be able to make something out, even part of the number might help. It may have been deliberately obliterated for some reason of course.
Looking at the diagrams on the
BRP PARTS WEBSITE might enable you to confirm my gues or other wise.
I notice that from1991 the ignition system changed from points to cd. Which does yours have?
It appears that the currently recommended plugs for all 3 hp models from 1952 to 1968 are J6C gapped at 0.030"
If it dies after a few seconds first check the plugs, the points the coils etc but I would gues it most likely needs the carb cleaning. Can you keep it going by playing the choke?
