How do you troubleshoot a boat 85 HP Black mercury motor that won't crank. Been sitting up over 1 year.?

Question

I don't know much at all about boat motors. This 85Hp black Mercury won't crank. What do I need to look for to get it working. won't even turn over

Answer 1

I'm in line with biff if the motor is seized up (locked up) try using marvel mistic oil you can buy this at wal mart in the auto section ..... remove spark plugs lift engine up all the way fill cylinders with oil allow to drip thru carbs then take a s***w driver to the flywheel with moderate force try to move it a tooth at a time in each direction keep filling the cylinders it will break free may take sum time to do so but it will break free...

Then try to turn the engine over either by starter or by rope to expell the excess oil, then try to start engine with fuel mixed 60:1 this is a very rich mix it will smoke like h**l but run it in a barrel of water make sure it is pissing water (water pump is working) then clean spark plugs and run a 50:1 fuel mix this is what your motor should be ran on anyway 50:1..... Be sure to use TCW 3 2cyl oil.....

Good Luck I hope this helps!!

Answer 2

From the way you describe it the motor sounds as if it is seized. This may be from sitting. Was it running last year? Try removing the spark plugs and spray wd 40 in all the cyls. Remove the cover and turn over by hand. Get a manual and it will tell you how it works!!PS..All mercurys are BLACK!

Answer 3

first get ur self what they call a mufler clamp atach to  rear of motor and plug a hose into it incase you get it running with it on dry land may burn something out. or can use a 45 gallon drum of water.

2nd, check for spark make sure you have power to motor, then check the magnitos

If not may be wiring.