1986 90 hp Mercury inline 6

[ab59]

about 6 *- months ago I bought a 1977 Starcraft SuperSport aluminum with a blown evenrude 140 on it. I bought a 1986 Mercury 90 hp that I hung on the back of the boat and then life got in the way, so to speak. Now I am trying to get ready for the spring bite, and I have just hooked up the shift and throttle cables and realized that this came with an oil injection system that had been disconnected from the motor. I do not want to run the injection system. How can I plug off the oil injector system and run pre-mix? There is also a long 1/8 th inch tube line that may be an oil gauge line or a water pressure line. Since I did not take it apart, I have no idea of what it is for sure, or where it attaches to the motor. The trim works but leaks down as well, that will be my next target. Anyone know about the oil injection on these motors? thanks----

 

[racerone]

There is a small diameter oil recirculation line that goes from the bottom of the block to near the top bearing.

 

[QBhoy]

Another school day for me. Totally wasn’t aware there was a straight 6 merc 90 with oil injection.

 

[racerone]

Those may have used that separate tank ----AKA ---Autoblend----And that unit should be thrown away as far as you can.-----The inline 6 was marketed as a 90 for quite a few years !!

 

[ab59]

Those may have used that separate tank ----AKA ---Autoblend----And that unit should be thrown away as far as you can.-----The inline 6 was marketed as a 90 for quite a few years !!

You are correct. This 1986 90 Hp Mercury motor uses the " Autoblend" oil injection system. I looked through the papers that I got with the motor and found the original service booklet on the unit. It has explained a lot to me but I want to remove it so the user booklet does me no good. I do see that the fuel line comes from the tank to the Autoblend where the oil is injected into the fuel and then an "out" line to the motor. Since it appears that the mixing is done at the oil injection unit, can I just simply remove the injection unit from the loop and run pre-mix? There is still a fuel pump at the motor, right? I am not familiar with these motors so much, so I want to make sure I don't ruin a motor that has had 1200 last year in restoration done on it, stator and all.

 

[Faztbullet]

Yep ..just toss Autoblend and install a hose splice where it was.

 

[ab59]

Yep ..just toss Autoblend and install a hose splice where it was.

thanks, I appreciate that.