What to do first? Sat for 5 years. Old Mercury 4hp Outboard motor

[Carl Wonderful]

Pull the spark plug ( get a replacement) and pour some oil down into the cylinder and let it sit for 24 hrs. Pull on the starter cable slowly to see if it turns or if the piston rings are stuck to the cylinder wall. If stuck get some penetrating oil and repeat the flush. Once the engine is turning test for an ignition spark. Once you confirm you have a spark remove the carburetor and rebuild or replace. (they get gummed up and the seals deteriorate). Empty the old gas can and make sure is clean and add new gas with 2 stroke oil at 50:1. If the engine shows compression and you have a timed spark with fuel it should start. Adjust the carburetor and idle speed and you should be good to go.

Thanks for the clear instructions. Couple questions about specifics...sorry I'm new to all this...

1. What kind of oil to pour down the cylinder?
2. Any idea where I would find a kit to rebuild the carburetor?
3. How do I adjust the carburetor?..
4. Does it need a specific spark plug?

I have the gas/oil mix and just ordered a compression tester.

Thanks for the help.!!

 

[dLj]

Thanks for the clear instructions. Couple questions about specifics...sorry I'm new to all this...

1. What kind of oil to pour down the cylinder?
2. Any idea where I would find a kit to rebuild the carburetor?
3. How do I adjust the carburetor?..
4. Does it need a specific spark plug?

I have the gas/oil mix and just ordered a compression tester.

Thanks for the help.!!

1. What kind of oil to pour down the cylinder? - Marvel Mystery oil is one of many that would work

No idea about #2

#3 - I'd have to see your carburetor - still might not know but I have worked on a lot of old carbureted engines...

4. Does it need a specific spark plug? - Just match the one that you take out. There should be a designation on the side. Could be an old number but it's usually easy to find a modern equivalent.

When you get that baby running - you better post a video with sound! Hahaha

dj

 

[MaryEllaRose]

Beware of carbs bought on Amazon. I bought one for my Tohatsu 9.8 and although it looked identical it was jetted so rich it carbon fouled the plugs in only a couple of minutes, filled the garage with black smoke. Amazon only gave me a partial refund because gas had been run through it.
Clean the carb, especially the small idle jet, use fresh gas with proper oil mix ratio and fresh plugs and try it. I’m willing to bet that 50+ year old Merc will fire right up.