Boat will not accelerate

[Justryingtomakeitwork]

I recently got a boat from my grandpa that had been sitting for a good while. It has a 88 mercury 40hp motor. I got the motor running but when in forward it runs 4-6mph no matter how much throttle I give it. When the motor is off it will spin while in gear and clicks each time. Any idea what could be wrong with it?

 

[racerone]

If it clicks when turning the prop clockwise in forward it is normal.-----Sounds to me that it is running on just 1 cylinder.----Test compression and test spark.---Also see if throttle is going to wide open.

 

[Gavin27]

Spinning the prop and hearing a click is normal when its off. You will also have to clean and rebuild the carbs. Sounds like your high speed jet is plugged up from sitting! Happens all the time! Its superrrr easy to do but can be intimidating if its your first time. Get your serial number and order a carb kit before you take it apart. You will need one kit for each carb. Make sure you take a photo of what it looks like before, incase you forget how it goes back together.

also, I highly suggest changing out the fuel lines as well. You could clean your carbs, start your motor and send more sludge into your jets!