Re: Info on a 1975ish Mercury Thunderbolt 850
g,day Zikka<br /> wellcome along and g,day from down under.<br />the fist thing we need to know is the serial no.

it,s the number on the pivot point under the mottor so we can be more accurate.

<br />all I can tell you is they made the 850,s in 1973 through to 77 and they are 66.6 cu in displacmentand put out 85 hp

<br /><br />cheers Daryl<br /><br />psIt,s money well spent when you get a work shop manual (seloc put one out as I don,t think you will get the mercury one any more)
www.selocmarine.com this web site should tell you more