"New" 2002 90hp carb'd 4 stroke - questions about care and maintenance

[Thirsty Endgrain]

Just picked up a used '02 90hp carb'd 4 stroke.

Going through it now, want to do all the maintenance before I get 'er on the boat.

New impeller kit, carb kits, have a carb synching tool on the way, lower unit oil, and engine oil.

What oil is best to use? From research it seems like 25W-40 synthetic blend is best. Is it also OK to use regular mineral oil? Is the west marine brand just as good/at least OK as the Quicksilver stuff? Since I'll likely only need to change once a year I'm not worried about a few more bucks for Merc oil, but if the WM stuff is just as good I'll save the money where I can.

Plan to use merc fuel conditioners, or techron. I've read enough scenarios now about how sensitive these engines are to fuel quality/water in fuel.

 

[Faztbullet]

As long as its a 25/40W and FC rated yer good. Run Quikleen every second tank of fuel. I recommend to my customers the run Quikleen or Yamaha Ring Free and some are using the Quikare additive. Dont know if these additives work but I dont see these engines them till end of year for servicing. And most are used daily...

 

[Thirsty Endgrain]

As long as its a 25/40W and FC rated yer good. Run Quikleen every second tank of fuel. I recommend to my customers the run Quikleen or Yamaha Ring Free and some are using the Quikare additive. Dont know if these additives work but I dont see these engines them till end of year for servicing. And most are used daily...

Thanks for that. I have some quickleen and quickare on the way.

So in terms of mineral vs synth blend as long as it's FC it's all good? The overkiller in me wants to go with the blend, so is that a matter of personal preference, or is this engine fine with either?

 

[Faztbullet]

Fine with either...