1971 Evinrude 4 HP. seafoam but no smoke.

Rick.

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Jul 30, 2006
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Hello. I did a seafoam treatment on my motor yesterday. I made a batch of seafoam/oil/gas mix, sprayed the cylinders the night before and started it up on the lake yesterday morning. I let it warm up to op. temp. let it sit for 15 minutes started it up and still no smoke. I had it going from idle to wide open. Does this mean I don't have a carbon build up or was the seafoam expired? When I say no smoke I mean only the normal amount. I also did a 4 HP Johnson at the same time with the same, no smoke, result. Thanks, Rick.
 

WTL

Seaman
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Jan 7, 2008
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Re: 1971 Evinrude 4 HP. seafoam but no smoke.

I didnt know seafoam can go bad. How much did you put in the gas? Sometimes I pour some down the throat of the carb too and that should get it smoking.
 

iwombat

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Jul 12, 2006
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Re: 1971 Evinrude 4 HP. seafoam but no smoke.

You probably put most of the extra smoke in the lake. That 4hp isn't going to burn up a lot of fuel anyway and it may be hard to notice the extra.
 

tashasdaddy

Honorary Moderator Emeritus
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Re: 1971 Evinrude 4 HP. seafoam but no smoke.

i would say you have clean running motors. congrats.
 

ezeke

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Sep 19, 2003
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Re: 1971 Evinrude 4 HP. seafoam but no smoke.

How long did you actually run the motors on the SeaFoam mixture?
 

Rick.

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Re: 1971 Evinrude 4 HP. seafoam but no smoke.

I ran the motors for 20 to 25 minutes each. I used the FAQ suggested ratio of 16oz. per 3/4 of a gallon. Now that I think of it I used an Imperial gallon which is slightly more than an American gallon. That would of left the mix a wee bit leaner. Rick.
 

ezeke

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Re: 1971 Evinrude 4 HP. seafoam but no smoke.

If there were carbon build-up that would have burned it off. I think TD is correct.
 

tashasdaddy

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Re: 1971 Evinrude 4 HP. seafoam but no smoke.

keep maitaining those motors the way you have, they will last for ever. but it will never hurt to seafoam again, in a year or 2. just maintenance.
 

Rick.

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3,740
Re: 1971 Evinrude 4 HP. seafoam but no smoke.

Well the seafoam must have done something. The night before I did a cold compression check and found both cylinders were at 85lbs. cold. Last night I checked them again, cold, and found the top @ 97 and the bottom @ 95. This is the first time this motor has seen a lake in several years so in spite of the lack of smoke the seafoam ( or just a good run) did improve the compression by a lot. Rick.
 

wilde1j

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Apr 15, 2002
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5,964
Re: 1971 Evinrude 4 HP. seafoam but no smoke.

You had stuck rings from carbon build up.
 
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