Well changing out motors I have a 300 mariner supermag going to 300xs with dbr and hydro tech tuner hope this motor is as good as the one I’m replacing wanting to get better mileage
Well changing out motors I have a 300 mariner supermag going to 300xs with dbr and hydro tech tuner hope this motor is as good as the one I’m replacing wanting to get better mileage
It should be better all around. Good luck.
The xs is a good motor. They run good and get great mileage. At least my stock one does.
What oil do you run in your 300 I don’t run mine hard so not sure on what oil would keep carbon buildup to a minimum
Actually merc racing oil best choice
Ron Fears
Stroker/300XS
1E003823
Merc racing far better at cleaning
Ron Fears
Stroker/300XS
1E003823
I have run Yamalube in mine for the last 7-8 years.
Pennzoil Premium Plus
I have been told that Yamalube doesn't carbon up like the Prem Plus. That being said I run the Merc oil as my motor is still under warrenty until next week. I have never had a oil related problem.QUOTE=NixaMan;10390223]I have run Yamalube in mine for the last 7-8 years.[/QUOTE]
The racing oil became recommended for the racing motors after the book was printed for my motor. I ran merc prem plus on my 07 300xs and as far as I know it it still running. I run it in my 14 300xs with no problems. I do run Aces in the gas to help with ethonal and other stuff and put some oil in the gas tank to help lubricate the air injectors.
Claims from mercury guys is that the formula has been around since the 50s and has superior anti carbon properties.
Ron Fears
Stroker/300XS
1E003823
Premium plus is without a doubt a good product
Ron Fears
Stroker/300XS
1E003823
Got motor on and running premium plus for now anyways can tell already it’s a lot better on fuel than old engine I ran about 2. 1/2?hours plowing water for break in and burned 33 gallons of fuel when engine is able to run up on pad it should really do good
Congrats on getting it on the water. The book on my current 300xs stated a 4 hr break in period while my mechanic recommended 10 hrs so that's what I did. 10 hrs seems like a life time but it it cures some problems in the future it's worth it. I also do the same on Lower Units.
Got three more hours on motor today before the big boats got out finally stopped double oiling the best I can tell today I ran around a 120 miles and burned 21 gallons of fuel more than happy with it so far should have done it a long time ago