I was talking to a guy at work about our motors.  We both have '95 Merc 150 Black Max's.  He mentioned that he never trusted an oil injection system, so he adds oil to the gas when he fills up.  Have any of you had a problem with a similar system?  I have owned the boat/motor for 7 years with no problems.  I make sure to winterize it before storage each year, have changed the fuel filter twice, and am having a new impeller put in this year. 

  Just looking for anyone's opinion on the oil issue.  Also, this motor has always idled kind of rough, but my mechanic and others have told me that that is how the Black Max is?  It does sing like a fat chick when running and starts up great.

I'd trust the manufacturer before a "guy at work" when it comes to engine operation.

Adding oil to the fuel only insures one thing, more oil getting dumped into the waterway, and fouled plugs.  OK, that's two things.  Want a third?  Increased operating expenses due to the first two.

You've run it for seven years, as recommended, with no problems?  Why change what has been working so well for you?

your engine has an alarm on it so if that oil pump ever fails it will go of and you wont blow up your engine.  i have a 1996 mercury 115hp with oil injection.

I use to have a 1986 black max oil injection.  The injection system went out so I replaced it with a fill in part from the local dealer and removed all the excess.  From then on I had to mix the fuel.  I would not double mix.

Never a problem with my Merc. I did have issues with an '88 Johnson VRO. Went thru 2 VRO pumps before I had it bypassed.

its rarely they pump that goes bad its the plastic drive shaft that goes bad and yes the alarm will go off but damage has already started when you hear the alarm. if it a older motor i say ditch that junk mix by hand and your covered   

The 80's vintage Mercs had a problem with the oil injection, resulting in blown heads.  These days there seem to be no problems with the oil injection system, but many of the old-schoolers still insist on mixing their own oil and disabling the injection system.

Thanks for the input.  I would like to see some more opinions.

I agree. I have 93 merc and had it seized up due to the fact the 93 cent tube was corroded and broke no alarm went off and it cost me 6k to fix.  I now mix by hand it is very easy and doesnt cost any more.  I would highly suggest to remove oil injector.  Don't listen to anyone who tells you different.  On the older Mercs remove the oil injector. 

Jenga

to quote Robert De Niro: "if you have any doubt, there is no doubt."

i mix by hand.