Optimax problem - Low pressure
I have an Optimax 200 mod. 11/99. Last summer the engine seemed to work properly. Having full open throttle the max rpm was about 5400 and speed up to 50 mph.
Last week I noticed that even with FOT max rpm was 4700-4800. Besides that problem, the engine is O.K. I checked the engine with a Digital Diagnostic Terminal and no problems were referred. Then I checked the air and fuel pressure. The air pressure was 65 psi and the fuel pressure was 75 psi, well below the acceptable range (80 and 90 psi, respectively).
It is a little bit strange because I have heard that according to the service manual engine will not start if air pressure is below 70 psi.
Several causes were given to me by the Mercury mechanic but nothing for sure. The problem is that among the potential causes fuel pumps and tracker diaphragm were mentioned (quite expensive).
Has anybody experienced a problem like that?