I just got my new 04 90hp Yammi 4 stroke . Of course they filled it with yamilube when it was installed and recommended that I continue to use Yamilube. I have also heard of some people using Mobile 1 synthetic on their 4 strokes.

What do you use???

why not use what's called out on the mfgr's recommendations?

That's how I do mine.

My Motor only gets Yamalube

Also I heard that you are NOT suppose to use the same oil you put in your car, It must be for Four stroke outboard due to the temp?

I just put 5W-30 in mine. What's the difference between Yamalube and motor oil?

I got this from another site
I would give Yamaha Technicians a call to fin out for sure.......Ross

Yamalube is good. I also use Chevron 5w-30.

I use Mobil 1 in everything i own. Including my Honda outboard. Its more money but its a far superior oil over standard oils. Especially in harder working engines such as outboards.

Mobile 1 4 stroke synthetic is designed for the outboard 4 strokers. I would use it or Yamilube if I was in your shoes.

I have never used synthetic oil . What are the advantage of it. Longer life .....Ross

I use Mobile 1 Synthetic in all my motors - cars, motorcycles and outboards.

I used to race Superbikes and that was the oil we used in our race motors. The Yamaha 400 superbikes would spin up to 14000 rpm. I have seen how good the motors would look inside after a mid-season teardown and have seen more HP on the dynos. Even after a 8 hour endurance race the motors looked really good inside and did not lose any HP on the dyno.

Damon

If the motor is still in the warranty window use the mfgs oil. Otherwise find a good premium oil and stick with it. Trying to save a few pennies can cost some serious $ in the long run. Voice of experience speaking.

Thanks for the help. I am not trying to save money ( the mobile synthetic is more than the yamalube). I just trying to find the oil and everything else that I need to make this baby last forever!!