Mercury 300xs excesive oil usage

[mercury01]

Hi i have just finished my 240min break in on my merc optimax 300xs. In 5 hours it used 2 us gallons of dfi oil. Is this normal? I was wondering in switchin for premium plus oil? What do you think? Also on break in i noticed that the boat had less power to plain than it was before. What could cause this? New plugs also installed. Thanks

[vnemous]

The engine requires DFI oil. That oil usage is normal during break in as the computer is adding more oil. During break in only 75% of power is available. Also 240 mins is not in stone. Motor must have a certain amount of load on it during break in to register. You will know when its out of break in its night and day

[kct11]

I run premium plus in mine. That's what the owners manual says to use in it.

[vnemous]

In 2010 Mercury put out a service bulletin stating DFI use and that they were gonna revise the owners manual.

Here it is straight from Merc:

New Oil Recommendation for All OptiMax Engine Models

Effective October 2010, Mercury OptiMax / DFI or Quicksilver DFI 2-Cycle engine oil is the recommended oil for all OptiMax models - including Pro XS. (The previous recommendation stated the use of Mercury Premium Plus 2-Cycle Outboard Oil in ProXS models and OptiMax oil in non-ProXS models.)
OptiMax / DFI oil is a superior oil when compared to the Premium Plus oil. While both products are high quality 2-cycle engine oils suitable for use in OptiMax engines, the OptiMax / DFI oil contains a higher percentage of additives that reduce carbon deposit formation.
Over time, under normal operating conditions, carbon deposits accumulate in the power cylinder (piston, cylinder head, liners). In most cases the carbon deposits do not create a problem, but carbon deposits that form on the piston - particularly behind the piston rings and piston skirts - can reduce engine life and performance.
OptiMax / DFI oil is specially formulated to prevent the carbon deposits from forming. It also does a better job of reducing existing carbon deposits than the Premium Plus oil. Going forward, the Operation, Maintenance and Warranty manuals for OptiMax outboards will recommend Mercury OptiMax / DFI or Quicksilver DFI 2-Cycle engine oil to help maximize engine life and performance.
Operation, Maintenance and Warranty and Service manuals are in the process of being updated and will contain the following:
Oil Recommendation

Recommended Oil

Mercury OptiMax / DFI or Quicksilver DFI 2-Cycle Engine Oil

Mercury OptiMax / DFI or Quicksilver DFI 2-Cycle Engine Oil is recommended for your engine. If Mercury OptiMax / DFI or Quicksilver DFI 2-Cycle Engine Oil is not available, we recommend using Mercury or Quicksilver TC-W3 Premium Plus 2-Cycle Oil. Severe engine damage may result from use of an inferior oil.

[mercury01]

The break in period is done.. 240 mins registered on load.. It has been rebuilt the motor . Any one knows the ratio for the oil usage?

[PanRonnie]

The break in period is done.. 240 mins registered on load.. It has been rebuilt the motor . Any one knows the ratio for the oil usage?

http://boatinfo.no/lib/mercury/manuals/200-225.html#/8

although i think the 300xs does 250 to 1 at idle
but am not sure

[kct11]

Its been changed again. Website says mercury racing. This I found on BBC.
Oil:
-These are the "top recommendations". Refer to your owner's manual for other oil specifications!
-ALL EFI/CARB 2.4/2.5/3.0L (2-stroke) Engines: Mercury or Quicksilver Premium PLUS
-All STANDARD Optimax (75-250): Mercury or Quicksilver DFI/Optimax Oil
-ALL ProXS Models: Optimax/DFI Oil. Mercury or Quicksilver Premium PLUS is acceptable, but Optimax/DFI oil is RECOMMENDED due to a better additive package to help combat carbon deposits.
-ALL Racing/XS Models: Mercury RACING 2-stroke oil, or PREMIUM PLUS
- (Note..... there was some conflicting information on Merc's Website- follow this recommendation for the latest information as it's released!)

[gregpro50]

Mercury Racing XS models take PREMIUM PLUS not DFI. Pro XS takes DFI.

I had to contact Mercury Racing directly to confirm this.

The reason is that the NON racing motors typically operate at lower RPMs and if you use the Premium Plus oil it is conducive to carbon buildup. There is a solvent in the DFI oil that breaks down the carbon and gives the oil less lubrication at high RPMs which is why the Premium Plus is recommended for the racing motors which have a higher redline than the non racing motors.

I personally use Penzoil XLF in my 250XS.