1969 Merc 500 (50hp) Spark plugs and impeller

[dandy]

I know this has been addressed countless times but I'm still not clear on what people are recommending for spark plugs for older Mercs.<br />I have a 1969 Merc 500 (50hp). The owner's manual lists a AC-V440FFK or Champion L78V. The previous owner installed NGK BUHW plugs which are actually a cross to the Champion L77V. I use this mostly for tubing (higher speeds). Any low speed trolling I do with a separate trolling motor. I'm also planning to drop the lower unit next week to replace the impeller. Any suggestions on plugs and tips on the impeller replacement would be greatly appreciated!

 

[Merc90HPnewbie]

Re: 1969 Merc 500 (50hp) Spark plugs and impeller

As for tips on impeller replacement the standard ones are to make sure you get all the nuts and bolts out before trying to get the lower off, sometimes there's one hidden under the trim tab, etc. Also make sure you put the impeller in the right orientation, some will not work if installed backwards.