43 lx problems

"I have a 96 maxum with a merc

"I have a 96 maxum with a mercruiser 4.3 lx with 2bbl carb. It runs ok up to half throttle but at half it won't stay at a constant speed. From 3/4 to wot there does not seem to be a difference at all.It makes a weird sound at wot like its missing or arching.
I have filled the tank with fresh fuel, changed the fuel/ water seperator, oil, oil filter, and plugs.
I pulled the plugs after leaving the lake and port side plugs are all dark and the other side all look normal.
Is this an igniton problem or fuel delivery?
Please help, Thanks brian"

"I along with like 5 diff othe

"I along with like 5 diff other people are having the same problem with our 4.3L mercs at wot. I've messed with timing, did a tune-up, drained the gas tank. Nothing seems to help and no one is able to give me any fix. I did go with a bigger prop so I might be over reving mine. Hmmmm....."

I heard from a friend they had

I heard from a friend they had the same problem on a different engine and it was the fuel pump. I am going to do a pressure test tomorrow. Could low pressure cause the ignition sensor to retard the timming?

check or replace distributor c

check or replace distributor cap and wires

"Is this an igniton proble

"Is this an igniton problem or fuel delivery?"

One bank of plugs is black; weak spark. Check cap for cracks and carbon tracking. Check/replace wires.

I am going to order a new cap

I am going to order a new cap rotor and wires. Do you think I should get a new coil too?

I keep a spare used coil on my

I keep a spare used coil on my boat.

Thanks for the help. I ordered

Thanks for the help. I ordered a new one and I will keep the old one on the boat.