Mercruiser 3.0 not hitting full rpms

[Jacks1523]

I have a 1993 Maxum SR I/O 17.5ft with a mercruiser 3.0

I have owned the boat for 2 years and it always starts and runs (when there's gas in it) But say its just me and I'm driving at full throttle i only hit like 3200 rpm's and 25 mph. i have a lift so there's no algae buildup, Say i hit the neutral button and give it full throttle it will reach 4600-4800 rpm's, i bought a new prob last year from the marina across the street and they said it was the proper one for my boat but i don't really know. i know my gas is good, i use stabilizer/seafoam, it has new fuel filters, spark plugs, wires.

this is my first post sorry if i did something wrong, and thanks for any help I receive!

 

[harleyman1975]

Start with the basics. check compession. Confirm firing order. Read plugs after a wide open run...should be tan.

 

[alldodge]

Howdy

Thanks for the serial number 0F016919, only issue I'm running into is the Merc site does not tell me if you have points, DDIS or EST ignition. Suggest check timing
Points or DDIS 8 BTDC
EST 1 BTDC (base timing mode)

Engine Compression would be a good thing to know (140 psi)

What is the prop pitch?