Mercury
Model 200L Carb
Serial OT834340
I bought this boat 2004 Procraft 200 Super Pro about 4 years ago. It had sat awhile and needed some work. I polished her up and got fresh oil and gas in the motor and it has ran pretty well for an old carb motor... It started to run rough later that summer so I took it in to the repair guy.
They replaced the fuel pump, water pump and rebuilt all 3 carbs. New plugs and it ran great.
At the end of last year it started to run rough again and I didn't do much to it other than drain and replace the lower unit oil before storing it for winter.
This year its is running terrible and sputtering on top end bad... It will fire right up and idle just fine and will get on plane slower than normal but at WOT it only runs about 40mph and sputters bad... I think im down a cylinder or two... I also lost my tachometer??? Voltage regulator maybe? Im thinking a bad ignition coil or something in the timing... Im not 100% sure, but Im almost positive its not fuel related. I ran two full cans of sea foam through it at the end of the year last year and it made no difference.
I have 105-110psi compression on all cylinders.
I have good clean spark plugs. ( they ALL look good and light tan in color.)
I have spark on all 6 cylinders on the muffs in the driveway.
I have confirmed 100% open butterflies on the 3 carbs at WOT
Not sure how to test much past this.
I am very handy with a voltmeter as Im an HVAC service technician
Any help would greatly be appreciated!