Logo
FULL SITE MENU

Old Merc outboard question...please help

F

Frank D

New member
Totally new to boating and outboards, so this question may seem pretty naive - actually it is naive since I am clueless. But, did Mercury make any older outboards that were oil-injected? I bougth a boat with a 1978 500 thunderbolt ignition 50 hp outboard (4 cyl 2 stroke) and I am fairly certain its not oil-injected, but I wouldnt even know where to begin loooking and I dont want to ASSume. I know if I have to pre-mix, its 50:1 with TC-W3 2 stroke oil - thats about as much as I could find out.

Any help would be very much appreciated.

Thanks in advance.

Franks
 
Yes, premixed.

I don't recall for sure but the first (onboard) oil injected models started turning up in the mid 1980's, and then first in the higher horsepowers (might have been 1989 before you could get injection on a 50 horse). There was an "inline" oil injection system called autoblend that was around a little earlier, but it had numerous problems and killed alot of engines when it malfunctioned (but to be fair, a good friend has a 1990 model, with an original auto-blend and it's working perfectly - he must have got one of the few that was built wrong :))

The 4 cylinder 50 is actually a pretty "desireable" motor. Lot's of guts and super well designed.
 
The mid-80s Merc triples (and others) used a bastardized setup with the tank and pump in the boat. The oil was pumped into the gas stream and--hopefully--mixed evenly between the carbs. Ugh! I'd really trust that abortion to work properly!

Pre-mix: it's messy but reliable.

Jeff
 
I remember not just early outbords but other 2 stroke motors back then where guys ignored the automix and premixed it anyway. It usually only took one meltdown to distrust the automix.
 
Back
Top