Mercruiser 4.3L not started since 2019, tips and advice on maintenance please!

[tanderson2002us]

Hello! Per the title I have not run my boat since I winterized in 2019. It has about 10 gallons of treated fuel in the 30 gallon tank. My plan is to disconnect the filler hose, run tubing into the tank and out the drain plug hole in the bilge then siphon the gas into cans for the waste transfer plant. After that I was going to 1. change the fuel filter, clean and gap the spark plugs, add about 10 gallons of fresh fuel then try to start it (with the muffs on at home). I want to sell the boat so just trying to get it up and running, new owner can do the full maintenance job. Its a carborated 4.3L GM sterndrive so wondering if I should pour something like seafoam into the carb to help the process. Any tips greatly appreciated!
Tom

 

[SternDriveEd]

Has the block been drained? Is it a closed loop style cooling system or a raw water only system? Check oil level. Other fluid levels. Charge battery. Air up the trailer tires. Trailer lights all work?

 

[Scott Danforth]

no way to run a tube into the tank thru the filler hose. the fitting does a 90 degree turn at the tank. pull the sending unit and go thru the top.

your carb will need to be rebuilt

change the oil as there is probably condensation from the last 3 winters
after the oil change, pull the plugs, and crank the motor over to get oil pressure

do an impeller job as the impeller will have taken a set.

 

[tanderson2002us]

Hello sir, yes its raw water cooling. Each year I meticulously winterized it, including draining the block, hoses, anything that holds water as I'm in Washington state. Ill check everything listed above this weekend, just getting started with the old gas. My concern is the carb...I fogged the motor like always but thinking after 2.5 years the carb is gummed up. Does the seafoam sound like a good idea or maybe just some carb cleaner? Really appreciate the reply.

 

[achris]

... My concern is the carb...I fogged the motor like always but thinking after 2.5 years the carb is gummed up. Does the seafoam sound like a good idea or maybe just some carb cleaner? Really appreciate the reply.

Yeah, no... You'll need to pull the carb and disassemble it to clean the internal passages. Spraying anything down the throttle barrels will only clean the throttle barrels, not the internals. And don't forget the fuel pump and fuel lines, they will also be full of stale fuel and varnish deposits.. That all needs to be cleaned out properly.

Chris....

 

[Scott Danforth]

There is no mechanic in a can