Rpm will not get to max

[Sea bass]

2006 amberjack 290 5.0 mpi will not go over 3400 rpm,s i usually get around 4k or 4200 rpm,s tried cleaning hull and props no luck

 

[Espos4]

Even 4200 max rpm is too low.
How long have you owned it?
Did it ever go above 4200 rpm?

What size props are on it?

How old are the plugs, wires, cap, fuel filter?

 

[mnm99]

Do a compression check, Check fuel pressure

 

[Sea bass]

Thanks for response. Props are original and it did get well over 4k rpm,s what i did over last few years i replaced both distributers I purchased them from Summit racing not sure if internally different in anyway

 

[Scott215]

Could be the advance curve

 

[blaster]

I used an aftermarket distributor cap and lost almost 400 RPMs but when I changed back to a Mercury part the RPMs returned to normal. Also be sure the firing order is correct and you aren’t running with a couple dead cylinders. If the distributors were replaced they may not be clocked properly. There is a special procedure for clocking the distributors. Make sure the caps are tight as well.

 

[Scott215]

They need to advance properly. Does op know how they were set up