evinrude Lark 3

[coolspot]

hello, I'm new here and wondered if anyone could enlighten me. I've just managed to get my engine running after it sitting for 2 years. It's a 1961 Evinrude Lark 3 40hp. I'm a little unsure of what mix to use. At the moment it's on a 25:1 mix but I've heard people find 50:1 mix better and less smokey) what damage could I do using more oil??


Cheers
Dave

[delboy]

hi, 50:1 mix uses less oil which would make it less smokey but you run the risk of overheating or such like if it needs 25:1, my old chyrsler would not run on 25:1 as it would oil up and not start so if yours runs with that ok leave it at 25:1 , but this is only my opinion, other people might know better,

[BluFin]

There is a vintage section on Scream & Fly that would be a good place to confirm

[andymac]

if you mix more oil you change the fuel\air ratio,i.e less fuel.this makes the flame burn hotter,which could put hotspots on your pistons

[larby]

Originally Posted by andymac

if you mix more oil you change the fuel\air ratio,i.e less fuel.this makes the flame burn hotter,which could put hotspots on your pistons

I've heard the theory about extra oil increasing the viscosity of the mix and therefore leaning out the mixture as less can flow through a given apature, but i'd never stopped to realise that changing the ratio would lean out simply down to the fact that far less of the mixture is fuel. I feel really really stupid now! Still, something learnt for the day, i can go to bed now!

James