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Two strange things with Merc 90HP four stroke today

Posted: Mon Sep 02, 2013 5:25 pm
by wrd1972
1. Upon startup, I saw some very black oil discharge (dots) get spit out into the water, likely through the prop. I don't think its engine oil because I purposely dropped some engine oil into the water from the dipstick and it had an entirely different appearance. It was not dark at all, it just was more colorful and different looking. I have not yet checked the level of the lube in the lower unit. If its lower unit lube, why would it appear at startup before the prop is engaged?

2. Started the motor with it in a rather warm state, and saw white smoke coming out of the plastic case and maybe the pee-hole. I think it was steam or again white smoke and not blue smoke from burning oil because I noticed no smell of burning oil. Went away after a short while and has not be repeatable. I have never detected the smell of burning oil. What was that?

Re: Two strange things with Merc 90HP four stroke today

Posted: Tue Sep 03, 2013 6:19 am
by oldmn19
You broke it,LOL, just kidding!!!!! It might, and just a guess, have spit out some rich fuel burn from a temporary drippy injector. If's it now running cleanly and doesn't repeat, I would still add a good injector cleaner to your next fill up, can't hurt! :2cents

Re: Two strange things with Merc 90HP four stroke today

Posted: Tue Sep 03, 2013 7:49 am
by lakerunner
oldmn19 wrote:You broke it,LOL, just kidding!!!!! It might, and just a guess, have spit out some rich fuel burn from a temporary drippy injector. If's it now running cleanly and doesn't repeat, I would still add a good injector cleaner to your next fill up, can't hurt! :2cents

Yes and that bit of gas dissolved some carbon and blew it out. The white is likely warm water hitting cooler air

Re: Two strange things with Merc 90HP four stroke today

Posted: Tue Sep 03, 2013 4:51 pm
by brumbyvet
Mine has done the same thing occasionally, since boat was new. It usually happens after I have had the motor tilted up, out of the water, for a week or more. Mechanic said not to worry about it and I haven't.