http://www.crowleymarine.com/johnson...cfm?mdl=N0QEGQ
Its part # 51....but this page of the catalog got messed up, the part is not listed correctly, the original # from my literature is 502905 and in the aftermarket (Sierra) the one you want is 18-7946
PS the number you have may be an outdrive number, it is not an engine model # which is what you need to get the right parts.
it will start with a 57 (5.7 liter) and have a 4B next (4bbl carb) then a P (if power steering) or M (if manual steering, unlikely) then there will be 4 more letters, not sure what differences they signify....
your model # (usually its on a label on the valve cover, or thermo housing) and then you can look up parts.
for this part it doesn't matter though, they are all the same for the V8 and V6 models of that vintage...
OE# OMC0502905
Sierra aftermarket:
18-7946 10 micron or
18-7846 21 micron
this site won't let me link directly to the BRP catalog website, but that's the best source of information for parts questions.
