merc 350 excessive smoke

[Lorne Walter]

I have a 1961 merc 350 40hp, in the manual i found online it says to mix the oil at 20:1 so I did. the motor putout so much smoke when trolling, it made us all sick after a few hours. Once in a while, the blue smoke will become so thick, we need to drive away a bit, and you can see clouds of blue billowing of the lake surface, then it clears out after a minute at full speed. so we can troll again. and any suggestions? this is my first boat so I am not well experienced.

 

[racerone]

Should be 50:1

 

[Lorne Walter]

Should be 50:1

I also agree it should be more like 50:1 but why would the manual state 20:1 ?

 

[fastjeff]

It was written way back then when oil was crap!

Jeff

 

[faztbullet]

The manual stated you use the 50:1 ratio if you have the thru hub exhaust and 20:1 if non thru hub. Don't know why but doubt its about oil being crap as its same oil

 

[fastjeff]

I was referring to that old, 30 wt crap (which was all we had back then) that carboned up and fouled plugs like crazy.

Jeff

 

[Lorne Walter]

It was written way back then when oil was crap!

Jeff

that would make sense lol