Both of mine are original, and 14 years old. Both engines seem to run well but one engine does not seem to come up to full RPM (4000 instead of 4400). Whats weird is boat speed seems correct and engines do not sound out of sync - might be a tach issue....
Fuel pressure is good, though with a little bounce from the vacuum modulator section of the pressure regulator (bounces about 2 to 3 PSI around 55psi, disconnect vacuum line and steady 55psi). Leakdown looks good after several minutes. Plugs are new, fuel pressure regulator is new. Fuel pump is newer (not original). Engine smells rich when idling, has a pretty good idle, not as smooth as other engine but very close. Got me thinking one cylinder not firing properly, though plugs all look good.
Having read about the caps, thought it might be prudent to change, and see if that also affects top RPM any and idling.
Engines have about 450 hours on them.
Just curious as to anyones thoughts...