69 Evinrude 4hp Seahorse Gas/Oil Ratio?

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Fishingking

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Mar 26, 2006
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Can’t seem to get a definite answer on what the Gas/oil Ratio is for a 1969 Evinrude 4hp Seahorse is <br />I believe it is 50:1 but wanted to make sure. Also I normally run High test in the engine is this Necessary?? I ran 87 in it once and remember it didn’t run so well.<br /><br />Thanks for the help<br /><br />FK
 
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steelespike

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Apr 26, 2002
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19,069
Re: 69 Evinrude 4hp Seahorse Gas/Oil Ratio?

Proper fuel mix is 50:1.Don't skimp on the amount.<br /> 87 octane should work fine High test is a waste.Some older motors list regular gas at 89 octane.If yours refuses to operate well on 87 try 90 or what ever is the next higher in your area.If it insists on high test there is something amiss maybe carbon buildup.In that case try a decarb treatment.<br /> Be sure to adjust your high and low speed mixture valves to the best operation.Make the final highspeed adjustment just a shade toward rich.
 
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Paul Moir

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Nov 5, 2002
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6,847
Re: 69 Evinrude 4hp Seahorse Gas/Oil Ratio?

50:1 is the correct ratio recommended by OMC. Always has been. But it's widely known to be inadequate for these engines. Use 40:1 or 32:1, with 87 octane fuel and TC-W3 outboard oil if you're after longativity. See the Oil Mix FAQ in the FAQ Forum for details. The 4hp only has a top main roller bearing and seal - all the connecting rod bearings and the other two mains are plain.
 
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Fishingking

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Mar 26, 2006
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Re: 69 Evinrude 4hp Seahorse Gas/Oil Ratio?

Thanks alot guys. IT only has one speed and thats fast in foward :) the speed contol thing doesnt turn well so Its always set for full bore. I am always messing with the mixture valve untill it apears to be running the best.<br /><br />thanks again.<br /><br />FK
 
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