I have a 1997 Mariner EFI 150 hp. I have used mercury synthetic blend oil mixed 50:1. It does not have its own mixer. I mix it my self.

I was topping off my front tank and I put enough oil for 5 gallons of gas and it would only hold 4 gallons of gas.

Will this make a difference in the performance?

Will it cause any negative consequences?

Thanks

Might smoke a little more

No. Not a problem.

Been there and done that... like Slone said, it may be smoking a little but its fine. And when i did add a bit more than you did and mine is fine.

Good deal. Thanks I will be the mosquito repellent tomorrow then.

I was told that it was better to put to much in than not enough........of course, that means that its a little more than what is required. I just read on a bottle of Stable that to much of that won't hurt anything either.

Newer motors are pretty forgiving if you have either too much oil or too little.  As long as you are close it should

run good, and you will do no damage.  If it is way too much oil the plugs can foul.  With a 1997 motor I am surprised

that it doesn't have oil injection.

I probably did have the oil injection.

It ran fine Saturday