[mfg1963]

I have a 2 cylinder 1963 40hp evinrude that billows smoke at low rpms. Its starts right up and runs great all day long but the smoke at low speeds is really bad. I'm using 50:1 with Wal-mart brand oil. I've adjusted the lean/rich adjustment but it makes no difference. Where do I start?

[Lark40]

I believe that your engine was designed to run at 24:1 not 50:1 oil mixture. The OMC engines switched to 50:1 in 1964.These engines, at the correct mixture, tend to be smokey.If the engine has power, and is pumping water OK, then the smoke may be normal. Not pretty or perfumey, but normal.

[Franki]

Hey Mr's Lark40 and mfg1963I have a Selectric Lark40,, what year did they start making them?? I have always ran it at 25:1 just cos thats what I always used years back when racing motorcross and I'm not used to the idea of using 50:1 safely..so I think mine is a 62, but maybe not.. either way.. I am ok with modern oil and 25:1??(I run my 72 Johnson at 32-35:1 because I can't bring myself to try 50:1 it seems almost unnatural to me to use that little oil...)Incidently, I always noticed abit of smoke from mine as well (the old evinrude), but not that much.. if I was you, I'd consider a decarb and then try a different oil...rgdsfrankrgdsFrank

[oldboat1]

Lark40 gives good advice. I think I would add that a lot of what appears to be smoke might really be steam, particularly if it doesn't hang around long. I had a '61 Lark (put it on an MFG, by the way) and it really blew a lot of water, steam and smoke -- in some combination -- out of the exhaust port. I stated on an earlier thread that I had better luck with a 40:1 or 50:1 mix on mine -- and got smoked a little for that (correctly, actually, because it ain't a good idea to go light on oil in the old motors). It would be safer if you got it to run on a heavier oil mix.

[oldboat1]

seeing Frank's post reminds me of something else that might be worth noting (We had compared notes a couple days ago on Lark 40s). The choke on my '61 Lark was operated by hot water. When the engine warmed up and the thermostat opened, the hot water flowed to the choke and opened the butterfly valve. Mine worked well without any tweaking, but maybe yours (if you have one) isn't doing the job -- engine may be running rich. Now that I think about it, when the choke kicked open on mine, the engine would lean out and settle down to a nice idle -- and the exhaust smoke would decrease.

[mfg1963]

Thanks for all the replies. I'll try beafing up the mixture a little and see what happens. This is my first boat and I'm being extra cautious. Thanks again for all the help.mfg1963

[Lark40]

Franki-,I believe that the Selectric Shift became a Lark option model in 1961. Think that my 1960 Lark was the only 40 hp year that had manual-only shift.