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I'm replacing the plugs on my 1974 Evinrude 50hp. I pulled the old pluge and they are QL77JC4, the only plugs I'm finding are L77JC4. Are these the plugs I need? Whats with the Q?
The L77 is hotter than the QL77
If the engine is non CDI, meaning points ignition, run a BR8HS (NGK) plug as they are availlable. Otherwize, stick with the QL77J4C Try IBoats, bet they have 'em.
The QL77JC4 and the L77JC4 are the same heat range. The Q will not create interference/noise in your electronics. You want to stay with Champion plugs in an OMC carb'd motor. That's what they were designed for.
The L77s will be fine. If you have a radio or fish finder or GPS or are using an oil injection type fuel pump then you'll be better off with the QL77s.
I have an evinrude Lark 50, 50473M 1974 2 cyl.
The plugs that the boat parts store gave me as the replacement plug are
NGK B9HS 10.
I ran them every weekend for over six months without a problem (and I do have a Humingbird fish finder).
I looked at champions web site and they recommend the QL77JC4. I found some of the Q's at NAPA and got em just to be sure i have the right plugs I'm having problems with getting the engine to run right so I don't want any doubts as I go through and eliminate possibilities.
