How much oil should a 2 stroke use?

My 2001 Merc 90 goes through about a quart and a half of oil (low oil alarm starts singing) after about a tank of gas. 18 gallons tank.

I’ve never made two tanks of gas on a tank of oil.

My father in law has a Johnson 90 and although it’s a bigger oil tank, can go all summer without filling the oil tank.

Is this normal?

Good question.

With my 115 Johnson I run through about 2 gallons (the size of my oil resevoir) every 4-5 tanks (I never let it get quite to where the alarm sounds).

I think my boat’s fuel tank is around 20-22.

i used 4 gallons last yr and with the price of gas i dont even what to know how many gallons of gas i used

Well if my math is right you are running about 50:1 wich seems about right.

My 2001 Mercury 90 uses approximately the same. It seems like it is using a lot since the reservoir is relatively small and needs refilling often, but when you calculate it out, it is reasonable.

Yepper my math too.
18 gals x 128 oz/gal = 2304 oz
1.5 qts oil=48oz

2304/48= 48/1

“50:1”

Doh! Look at that… math actually works!!

I should have paid more attention in class.

Jeez Brian, why don’t you think before you post!

Now you know the oil to gas ratio, now check your owners manual and see what the company recommends.

I don’t know about Merc, but I used to own a ‘Rude that was 100:1 meaning your Merc would be using two times the oil my old 50 horse used.