Honda BA15hp FOUR STROKE (NOT GETTING MAX RPMS)

Hello Everyone,
I am new on here and need some serious help with the above outboard engine please anyone.
Ever since i have had this outboard i can only get a max rpm of 3700rpm.
As they are rated at 4500rpm --5500rpm as per Hondas spec.
It is a 2000 year model(here we go ) Is it a CDI problem not performing underload??
My Boat is a light 16ft skiboat and i have a Honda Tachometer set up as per spec.
I have just put on a solas 9x7 prop and it makes no difference at all to the rpms
The Engine sounds " Tinney when it revs up underload and holding back like it just cannot achieve the rpms.

I am not prepared to spend anymore money on it until i can get some serious help and advice to try and solve it if i can otherwise i shal just sell it and go back to 2 STROKES.

HONDADUDE. I HOPE YOU SEE MY POST.

My experience with RPM under performance, the first culprit and most frequent are the following:
1. Old fuel lines breaking down and creating clogs in carb or fuel filters restricting the proper amount of fuel to the cylinders to burn and achieve max rpms
2. Old fuel lines and loose connections causing to much air entering the process screwing up the fuel to air ratio needed for optimum burn and max rpms
3. Poor spark in one of the cylinders
4. Last resort and worst case scenario is poor compression.

I would start at 1 and 2 and if that doesn't fix it, look at 3 and check the spark. If none of those work, then it is onto compression. If you have bad compression you will need to do a ring job, which isn't bad on those small engines.

Typically, as CDI issue is your engine just won't work at all. Kind of like when your car has a chip malfunction or fail your car won't even start.

It should be one of the above. Compression testers are free from AutoZone and O'Riley's on the loan program and super easy to test.