1998 mercury promax 300

[smiley88]

whats up fellas I know there has been discussion after discussion about pulling the oil injection systems off of the pro max 300 I have a 1998 mercury 300 Promax that still has the oil injection system on it I am very tempted to pull it off. what recommendations are recommended for oil mixture ratio for the 300? And thank you in advance for Everybody's time that chimes in

[Sea2jet]

When Simon Motorsports built my 335x's they deleted the oiling system. I was told to run 40:1

[xskeetshooter]

well if its worked for all these years, why pull it?

[smiley88]

Would just like to be safe is all.like to run fast and just want to make sure motor is guaranteed oil...the 300 promax is only couple years new to me..my 280 on allison I mix 32:1 , was hoping I could keep mix the same on promax 300....some say 50:1 some say 40:1.others say 32:1 is ok...was just trying to get opinions from others with problem free experience. .

[vnemous]

I have been running my 250efi at 50:1 for years with no problems. Will depend on the rpms you want to run IMO.

[Onetime]

Got a 300 Promax here that the oil injection gear let go. Not good! The shredded up plastic gear broke through the block. No longer runs oil injection.
The 300 oil system was just before the ECM controlled electric oil pump. Pretty sure oil injection failures was one of the reasons Mercury switched to the electric pump.

As others have said depends on how hard you run. 50:1 is what the one with the deleted oil injection above runs. 32:1 like the 280 runs might be a bit much.

[chad.r]

I have a 1998 300 pro max. I mix my oil 40.1, I use mercury performance plus oil. This is what the engine builder recommended for me, also my efi rpms have not been raised there still set at stock. I don't know if this matters with oil injection but i have a mad efi intake and fuel rail on my motor. I asked why not mix 50.1, and I was told that at 5800 to 6300 range that was what the oil injection mixed at. Keep in mind I was told this information, I didn't know it.

[cali kid]

I have a 1998 300 pro max. I mix my oil 40.1, I use mercury performance plus oil. This is what the engine builder recommended for me, also my efi rpms have not been raised there still set at stock. I don't know if this matters with oil injection but i have a mad efi intake and fuel rail on my motor. I asked why not mix 50.1, and I was told that at 5800 to 6300 range that was what the oil injection mixed at. Keep in mind I was told this information, I didn't know it.

I have a pair of Simonized 300 PM's on a 30' Cat. Using Premium Plus at 40:1. Can't kill them running 6000 sustained.