Can any of you outboard mechanics or dealers recommend whether or not I should disconnect oil injection on my outboard and start pre mixing? My 2013 Mercury 150 ProXS was purchased new in April 2013 and has been operated below average the past 6 years. Due to age, I was considering reducing the risk of oil supply failure.

Just don't want to neglect something like this when I can do some preventive maintenance. I was told many years ago to disconnect oil injection after about 6-7 years for peace of mind. I have inspected everything under the cowling and it all looks and feels like new.

Thanks in advance for any advice!

I captain a charter company that has 1997 2 stroke Merc engines with 2900 hours. Not sure why you would unless you are having any issues. If it is working properly why fix it?

My bay boat that i guide out of had a 2001 Yamaha with 2100 hours. No issues.

I see no reason to do this.

Does your model have a remote reservoir tank that feeds a smaller tank on the motor? Or is the big tank under the cowling? My yamaha had a reservoir tank in the boat and a lil fill tank under the cowling. The reservoir had a lil pump that filled the second tank. That transfer pump went out once, i got an oil alarm, saw tank full of oil, opened cowling and had to fill the lil tank at the motor by hand. Which worked fine. Changed the transfer pump and worked normal. Sold it a while back but still working fine.

Run it low (with spare 2 stroke oil on board) and confirm the low oil alarm is working.

I agree with Sgrem. I am running a 2000 Johnson 2 stroke and the alarm works just fine along with the injection. Ive been told I should disconnect mine as well. But I refuse to break something that works perfectly fine as it was designed.

As mentioned, engine has low hours and I am not having any issues. With that being said, over the years there have been many outboards fail due to loss of oil injection. A friend of mine was fishing and when he made a run to another fishing spot, his 150 Mercury died. He cranked it up and noticed it sounded strange so he shut it back down. He removed engine cowling and noticed oil dripping from busted oil line. His engine was 9 years old at the time and his mechanic suggested changing oil lines every 5 years or disconnect injection before a problem occurs due to age.

My friend replaced his outboard with a new one and said "amazing that a cheap .50 hose could lead to this". I've been paranoid ever since that incident 20 years ago!

Steve, you are not breaking something that works perfectly fine. Based on that theory, never change your truck hoses, belts, or oil and see what happens.

On the older carb'd and efi Mercurys the oil pump was driven by a plastic gear. While not all that common they did fail. People would remove the pump and put a block off plate where it mounted and use pre mix. With the Optimax you cannot remove it and run pre-mix, its a complete different setup. With DI motors the oil pumps directly to the crank and is not mixed with the gas.

Being a opti max you can not pre mix your gas and oil

Agree. I'm rebuilding mine tomorrow when the repair parts kit gets here. I've already taken the VRO off and waiting. Metering oil in with the gas as the flow increases or decreases seems to make sense to me. 20 year old Evinrude, Had the VRO changed out once and now I am rebuilding. I think it controls excessive carbonizing. But I'm a shadetree mechanic.

tmd11111 and boatman025, thank you both for the info on Optimax direct injection motors. I'm not going to worry about it, I will just keep maintaining like normal and monitoring!

Clean the main oil tank screen yearly.

I got mine taken off on my 97' Merc xr6 150, and it feels like it runs better now...

I'm not a mechanic. Mine is a 92 Mercury XR4 BlackMax and I still have the oil pump on it. No idea how many hours it has. I've only had the alarm go off one time running in really rough water. Ran to the shore, pulled the cowling off and everything looked fine. Started back up and ran fine after that. I've replaced hoses and cleaned the screen and it's been working fine for the 10 years I've had it.