gas additive

[jedi]

I just purchased a "69" 20 horse johnson. Do I need to mix a lead additive with the gas, and what gas/oil ratio do I use ....

 

[USS Neversail]

Re: gas additive

I am no expert, but from reading MANY posts on this, the ratio that is mostly recommended is 50:1. <br /><br />I am not sure about your particular engine, but the general concensus on this board is that no lead substitute is needed. 87 Octane gas.<br /><br />Hopefully one of the smart guys on this board will swing in and give you a definite answer.<br /><br />Good luck! <br /><br />Jason

 

[JB]

Re: gas additive

Hi, Jedi.<br />Neversail has it right. Even when leaded gas was common, manufacturers recommended unleaded.<br /><br />Good luck.

 

[epresutti]

Re: gas additive

Jedi,<br /><br />Just watched the history of gasoline on the learning channel. Lead was used in the refining process to boost the octane. Since the 70's other methods were found to produce the same result. This was due to federal and environmental concerns and regulations.<br /><br />Lead was added early in the refining process (step 2 I seem to recall) and served no other purpose other than causing the molecules to form more octets of carbon chains(octane). It contributes no other properties to the gas. They use pressure and heat in addition to "additives" to achieve the desired results.<br /><br />I think the highest octane we can get now is 93 or 94 in automobile gasoline, these levels were not available except in specialty fuels for racing and aircraft in the late 60's. So my assumption is that unleaded 87 would be fine.<br /><br />I am basing my comments on what I learned from TLC on the properties of gasoline. Or at least what I think I remember.<br /><br />Hope this helps.<br /><br />Safe boating to all.<br /><br />Cheers.<br /><br />emp.

 

[jedi]

Re: gas additive

thanks for the help guys!!!!!!!