Need info about Mercury Motor

[or_mercury_motor]

Bought a used Mercury motor last week at a garage sale. Cheap price, but no manual. The person I bought it from said it was a Mercury 20 HP (Thunderbolt) and the feul mix was 50:1. The only serial number I can find is 4053449. Could someone please tell me the proper feul mixture,year, and were I might be able to find a manual. Also if you have any idea about why it smokes excessivly when running I would appricate your insight. <br /><br />Thanks

 

[sprinkler]

Re: Need info about Mercury Motor

www.clymer.com<br /><br />Or try BoatU.S.

 

[ryanc]

Re: Need info about Mercury Motor

i have a mercury 20hp thunderbolt (1973). Your year i'm not sure on, but fuel mix is standard 50:1. As for a manual I would go with a OME Factory shop manual. They may cost more, but they will cover your motor. I made the mistake of getting a Clymer Manual to build my outboard. This manual covered other motors and was very confusing. Go with a OME manual. It will pay for it self. Ryan Cobb <br /> <br /> p.s you can find them right here at iboats.com

 

[andrewkafp]

Re: Need info about Mercury Motor

http://archive.bibalex.org/web/20010801165541/goa-northcoastoil.com/tips/obmixing.html <br /><br />All Mercs are 50:1<br />200 (20,0) 3755885 - 4102789 1974 2 cyl<br /><br />Smoke can be caused by a rich mixture .. like 40:1 or 30:1, Overheating (How hot is water from telltale) Has impeller been serviced recently ?<br />Or by some 2 stroke oil left in the carb or fuel lines or misting oil left in crankcase from storage.<br />If the telltale has good pressure and the water is only warm, run it for a while to get any excess oil out and running on FRESH 50:1 mix.<br />If it is still very smokey, look at air/fuel mixture adjustment.Clymer MERCURY 3.5-40 HP Outboard, 1972-1989 Manual Part Number: CLY B721 suits your motor.<br />BTW 2 strokes are smokey when cold <br />

 

[IBrokeMyFreakinNeck]

Re: Need info about Mercury Motor

You can buy a manual from Mercury Parts Express for $35 plus shipping.

 

[rickdb1boat]

Re: Need info about Mercury Motor

Do a compression test on it before anything else....

 

[Chinewalker]

Re: Need info about Mercury Motor

If you're running the motor in a barrel, it'll concetrate the smoke and make it appear more smokey than it really is...<br />- Scott