mid 1980's merc 40 HP

[curtito]

I do not know a lot about outboards but have recently bought a boat with this engine on. Runs fine for the most part but I am sure it needs a tune up. Problem 1) when i first launch the boat and start it up...it is fine. I leave it run a few mins to warm up. If I do try and give it lots of gas...it might go about 5 mph with pedal floored. I have found I need to **** around and throw it in reverse a few times. the engine bobs back and clunks. Then i put in forward and it will usually go. Just have to do this once and it is fine for the day. Odd
2) Sometimes when giving it juice it just stalls or has unequal rpm's... goes at about 25mph, dies to about 18 and then back up. Tune up I am sure.

 

[Laddies]

Re: mid 1980's merc 40 HP

It sounds like it's loading up and rev. don't require the engine ti work as hard as fwd. so once you rev it in rev it cleans it out. Maybe plugs. carb adjustment or even cleaning the fuel system