Re: Yamaha F100 oil pump replacement?
For a job like that, you'll want a factory manual. Unfortunately the Yamaha manuals really arent very good. But the aftermarket manuals are pretty general and might not have certain specific information.<br /><br />I currently have a 115 EFI Merc apart. I'm sure it uses the same pump. You'll have to remove the powerhead. It's not as awful as it sounds if you have a decent lifting apparatus. If you're going to lift it by hand, good luck! The pump will be bolted to the adaptor plate under the powerhead. It comes off with 6 bolts. There are two locating pins you must not lose. There are two o-rings sealing the intake and outlet for the oil. I'm betting you'll find your problem is with one of them. Mercury's replacement o-rings have a coating on them that helps them seal and not stick. I'm betting the Yamaha ones are just plain o-rings. You might want to consider Merc's but I doubt it's terribly critical.
