Hopefully someone can help or point in right direction. I have an 2008 Fountain 35 Lightning with staggered 496HO. My port engine gets 4750RPM and my Starboard engine is only getting 4450 RPM. I'm only hitting low to mid 70's. I have Maximus 5 bladed props with 31P that were just balanced. Any insight will help.

Scan the engines and look for guardian mode faults - then look at available power in the scan --- I bet its showing like 90 % or 89 % or maybe even less for available power.

Balance props and repaired on top of ?? Bad rebuilt ? Or some form of prop issues after prop work ??? any current prop damage,

or low compression of that engine.

bad coils / and or spark related issue - possible spark plugs and or wires

scan tool is needed for sure

If you are DFW Texas let me know, .I have everything

Lots of prop for 496 HO's. What ratio drive do you have? Bam speed formula and prop slip formula's indicate high 70's or very low 80's. New style 33 only runs low 80's with 496 HO's. Sounds like you need more power.

http://www.rinda.com/techmatepro/

Too much prop for that boat. 700's would run them blades.

what gear ratio do you have??a lot of Fountains had 1.65 to 1,,if thats what you have then the props should not be your issue,

Its an 08' fountain with 496HO Staggered, XR drives, shorty sport master lowers. 1.35 gear ratio. 5 bladed Maximus props, 31P. Boat came from factory with this set up. Boat ran with this set up 5100 rpms @ 83MPH.

Im very surprised the HO's can spin those wheels 5100 with a 1.36.........

I know a boat that spins 31p p5x that cracks 100+. I just don't see that ratio and 496s working

Everything that BUP said is correct.
I have personally seen Crankshaft Position Sensors on 496HOs go bad withOUT showing a code or Guardian mode; that cause an engine to be down on RPMs slightly.
BUP helped me through this a few years ago.