Just saw at the local dealer that Mercury now offers a synthetic oil. Only a dollar more per quart when purchase by the gallon. What are the PRO'S and CON"S of Merc's synthetic?

I beleive it is only a semi-synthetic (synthetic blend), not a true full synthetic. Your money would be better spent on Mobil 1.

I thought the Merc. Synthetic Blend stated it was for Outboard Verado's. I read where Mercury has voided some warranties in the 496 & 525 efi's becasue the owners used synthetic oil. Merc. was saying that the rollers on the lifters were sliding on the cam shaft in stead of rolling (Teague contests this theory). Make sure Merc. allows the oil in stern drive engines if you are still under warranty.

States on container for all sterndrives and inboard engines. So this must mean it's ok for 525efi's.

My dealer only had the outboard synthetic in stock. If it says for sterndrives, I will be using it!

I just spoke with the Mercury Racing tech support at 920-924-2088. They said DO NOT use the Mercury synthetic blend oil in Mercury High Performance (blue) motors. They said to only use the Mercury 25W-40 oil. The new Mercury syn. oil is only for "standard" Mercury 4 stroke engines. I was hoping to be able to run synthetic in my 525's but I guess the "experts" are saying don't do it!!!!

Merc also states to use Kendall 20W50 in their new 600's. Those motors be blue...or red, or green, or whatever color you are willing to pay an upcharge for.