Just bought a 40hp Mercury off ebay

Hey everyone, new guy here and new boat builder. I recently bought a 1982 Mercury outboard off ebay for $500. He said the boat runs but it spits and sputters and doesn't run good, he thinks it just needs a carb cleaning. Is the carb the common problem with this or am I facing more serious issues with the motor?

Just wondering if I got a good deal or not, and if its a carb cleaning it looks like I did.

 

Maybe yes, maybe no. Old Mercs are not the easiest to make right. First thing is to buy a book for maintenance of Mercs that covers that year and hp. Second thing is to replace the water pump impeller before you try to run it very much. One source for information is:

http://www.outboardrepairs.com/old_outboards/#old_mercury_outboards

Another is: http://www.yankeeaomci.org/mercury.htm

 

Thanks for the info, Tom. The guy actually threw in a Clymer manual with the engine so that will definatly come in handy.

Does the water pump impeller tend to break easily? I've got all summer and winter to work on it so I'll definatly be replacing it. Any other areas I should look over?

 

Just sitting for a long time deteriorates the impeller and it can take a set that ruins its usefulness. After you get it out you will see what I mean. They are cheap and a new one can save the engine. I may be getting one like that soon and although I think old Evinrude/Johnsons are much more reliable and easier to restore, I still like the Mercs. I am really no more an expert than you, just like messing with them and keeping old iron going. I have a 53 Merc Mark 20 in great condition that I haven't got running yet.

With modern oils, you can run with a much higher gas/oil ratio. At least 50:1 and maybe more in some cases. Makes your green friends happier or at least less unhappy.

 

Your a brave man. The thing about outboards is they are alluminium and mostly used in salt water. At that age they generally pull out threads in just about everything you unbolt.

You need a touch and feel like a midwife and will need easy outs drills and tapping tools. In this condition they are horrible things to work on an are often just thrown away.

I would start by putting it upside down in a drum of diesel for few weeks

 

I dont agree frosty .....Hot Diesel you mean !!!