08' Merc 90hp --Ditching The Oil pump/going mixed fuel..

[frustratedboater]

I have a 2008 Mercury 90hp looper, "ELPTO" . SERIAL: 1B712639
Just a little history on this motor, a friend bought it and it had blown the top piston into pieces. I am helping him rebuild it.. I had a local machine shop bore the bottom two: .20 and the top at: .30. WE both don't have much history as to why it blew, but he would like to run a mixed fuel and not take any chances.
Other than disconnecting the oil, is there any other necessary steps needed to successfully operate the motor in the future? I don't see and electric lines to the pump, just the tank. Thx

 

[Faztbullet]

Got pics? A piston in pieces could be fuel,temp or ignition problem. The looper models dont like to be be overproped and lugged or ran more than 5-700 rpm over max rating. The piston skirts has a tendency to break

 

[frustratedboater]

Got pics? A piston in pieces could be fuel,temp or ignition problem. The looper models dont like to be be overproped and lugged or ran more than 5-700 rpm over max rating. The piston skirts has a tendency to break

Yes.

 

[frustratedboater]

Sorry for the huge size, I can't seem to figure out correct sizing on this site. The prop size is a 17-pitch on a 17 Trophy, fiberglass CC. Looking at the piston it looks like it crumbled. Flaw in design? I put the spec pistons in Wiseco in. Looking at the pistons, could be an oil issue. I'm not that experienced analyzing wear indicators..

 

[Dave1027]

To remove the auto-blend oil system you would remove the oil tank and the mechanical oil pump and associated oil lines. Should install a plate to cap off the hole where the oil pump was. Also plug of the oil port going to the fuel pump.

 

[Texasmark]

I removed the automatic oiler in my 2002 90 hp. It was really complicated......I undid 3 screws holding the pump in place and temporarily disconnected one oil line attached to it to get the pump out where I could grasp the geared drive shaft and pull it out.....which I did. I put the hose back on the pump and put the pump back where it was andreinstalled the 3 screws.

The complicated part was that I wrote a note adjacent to the gas filler cap on the boat indicating that I had to pre mix!!!!!!

 

[Faztbullet]

Skirt broke. Make sure you break-in the the Wisecos several heat cycles before WOT use. Check RPM

 

[merc850]

If you don't have a tach get one and make sure the motor is running near the hi end of its operating range at full throttle.