Merc. 200 EFI tach. prob.

[rockusilly]

I have twin Merc 1997 200 EFI,I spun the the hub on the port side motor so I repaced both hubs. Rpm,s were running the same before I replaced them, now the port side motor is showing 1000 rpm's higher the the starboard side even at low speed. It does not sound any higher by the naked ear. could it be bad tack, voltage reg. or something else. also this was the engine that spun the hub and it was at high speed but was backed down as soon as it happen but I don't know if anything could of happen in lower unit

 

[sleepinin]

Re: Merc. 200 EFI tach. prob.

Since you have the benifit of two tachs why not switch the input wires so the port side of the tach reads the starboard and the starboard reads port. If the problem follows the engine then I'd start looking at the voltage regulator. If the problem dosen't follow then I'd think the high rpm's during the spun hub incident got the tach.