Add oil in gas? or no.....
 

I recently bought a 30' Donzi ZF w/ twin Mercury 250 EFIs. The engines are oil injected but I was told to add some oil to the gas anyway to keep the injectors lubricated. Is this true should I add a quart when i fill up?
Thanks

Dealer:

I wouldn't. If your engines are stock, too much oil could actually build up as carbon deposits in the combustion chambers, sometimes called "coking".

THis is because oil burns hotter than the fuel, so if you run it rich on oil, it could "coke" up, and that's not good.

Mercury Marine spent gozillions designing those motors/injectors. While no company or design is perfect, if they don't tell you to add extra oil, don't.:)

My $.02

Good luck with your Donzi!

What are you nuts?
 

Besides the carbon buildup, you will be replacing plugs more often than normal. :D

ive heard that you should add oil to the gas for the first fillup to help with the engine break in

cardoctor