I bought a boat with a Mercury 20 HP 2-cycle motor. Serial number indicates itís a 1986. The motor runs ok but a little ruff. I think a tune up would help greatly, Just need to find some one close by too do it. I want to have it checked out be for I take it out on the lake.
Buy a set of plugs change. Run a can of sea foam through it . You got your tune up. Change lower unit oil. Total cost -$20. Price at repair shop $100+. With those older 2 strokes I changed the plugs a couple of times a year. Cheap and it prevents those pesky trips to the shop. If the fuel line hose and bulb hasn't been changed in a while change those also.
If you still need to take it to a shop be prepared for a long time in the shop. Big motors big money. Little motors little money. I was talking a guy in our local shop near Pymatuning and he said they are backed up, any motors being brought in will be at least a month to get them repaired. If it is a big job longer.
Thanks spunky I put an order into Wal-Mart for the sea foam, lower unit gear grease and grease pump. Wal mart doesnít carry the spark plugs. I can pick them up at Advance-Auto. I am a little leery about adjusting the carburetor. Hopefully the sea foam will do the trick. If not there is always you-tube.
Hornady I had an old Johnson from the 60's sitting down in the cellar for years. Decide to get it out and do the tune up. It started and ran with out repairs but it would bog down and run rough after a little while. Added the sea foam and started it up. Blew a lot of black smoke out the exhaust. Changed the plugs and installed the new ones and it runs just as good as the day it was first made. The carb will get a coating that looks like varnish in it, the sea foam will remove it and open the jets. This will smooth it out. You shouldn't have to do any adjusting to the carb.
Thanks again everything I ordered from Wal-Mart is in. a couple items were on back order. I will let you know the out come. The prop looks good, I saw a video on you-tube on changing the water pump. I may change it this winter. From the video it did not look to be that big of a job.
Go on marine engine.com or i.boats repair forums.Tons of help and info on any make of outboard.I use it for my older johnsons, as well as youtube.Old outboards can drive the best mechanics nuts due to more than one owner and too many adjustments being made.