No power !

[Ron1958]

I have a Mercury 75 hp serial number OG128530
Will not run over 25 mph. Mechanic said the carbs needed rebuilding ? . Rebuilt all 3 carbs and fuel pump and still have same issue. Then another mechanic said the power pack limiter was bad . Then another mechanic said this motor doesn't have a power pack it is one of the coils. Any suggestions ? Can't keep taking it to a bunch of mechanics and each one tells me differently and is getting costly

 

[jimmbo]

First you do is check to see if the throttle cable is properly adjusted and that the carbs are opening fully. If that checks out, then do a compression test. Then test for spark using a spark tester. Check timing and carb-ignition sync. Check fuel filters, fuel lines.

 

[flyingscott]

Do a cylinder drop test sounds like it is running on 2 cylinders instead of 3. Take a plastic pliers and pull the sparkplug wires off one at a time when they come off they should all affect the idle. The one that does not make a difference is the one not working. You have a powerpak AND 3 coils