75 hp optimax low air?

[CNT]

Motor runs rough and stalls at idle. I can't keep it running any lower than 2000 rpm. Firing on all three, and just cleaned fuel system.
What kind of air pressure should I get from the compressor on my 75 Opti. and what is the best way to test It ? Also what should the fuel pressure be? Any info. is greatly appreciated.


Thanks

[merctech5591]

90 air 105 fuel.. This is plus or minus 2-3 lbs.. If air is out of spec, pinch off the dump coming off the rail and see if air spikes to 120. If it will not u may have a bad a/c. Remove cover an inspect piston and reeds .. I had a similar issue come in.. Customer did his own service and ended up putting the wrong spark plugs in it..

[CNT]

If it spikes to 120 with pinched off line what then?

[CNT]

You hit the nail on the head. After fixing fuel pressure problem (ethenol eat pump grommet) the motor still ran like crap. I then discovered that the spark plugs the parts Guru gave me were autolite crossovers and not the original NGK's. I put the old plugs back in and it runs fine. "why you got to be so sensitive" Freekin Optimax! LOL! Also don't understand why their asking for 21 dollars a plug.

[merctech5591]

You hit the nail on the head. After fixing fuel pressure problem (ethenol eat pump grommet) the motor still ran like crap. I then discovered that the spark plugs the parts Guru gave me were autolite crossovers and not the original NGK's. I put the old plugs back in and it runs fine. "why you got to be so sensitive" Freekin Optimax! LOL! Also don't understand why their asking for 21 dollars a plug.

Shop around merc originals are that expensive .. Try your local autozone, advanced. Make sure they get u the exact number from ngk..

[CNT]

will do

Thanks