L250TXRR Slight missfire, intermittant loss of 300 rpm

I have a pair of 250txrr(s) and the port motor appears to have a slight miss at idle, it has a shake as compared to the starboard that idles smooth. It would lag 300 rpm behind the starboard motor, continuously when I purchased the boat. I have replaced all 3 fuel diaphragm fuel pumps (fixed a surge problem), changed all plugs, disassembled and cleaned all of the carbs. Before the carb cleaning the engine would not idle at operating temp (it would idle when the enrichment valves were open). Now it idles well at operating temp. But it has a shake or twitch when observing the cowling every 3-4 seconds, looks like a miss. When cursing at 4600 rpm the starboard motor stays at 4600, the port will run at 4600, and drop to 4200-4300 then come back. It seems to be random. WOT before I cleaned the Carbs was 5300 with Starboard being 5600, now the port will hit 5600 when running ?right?. Have good fuel and have changed the racors. Looking at the carbs at 4600 rpm, they are all spraying fuel from the main jet, but one can hear the engine cut out every 2-4 seconds (like miss one cylinder and immediately come back). I didnt see any fuel coming from the power jet at 9:00 position

TPS checks on ohms, but I need to reset it. My manual says to set at 0.54v , and I read a post from rodbolt that said 0.47 +/-0.01. Can I get confirmation on which setting is correct?

I also read posts to check the fuel pressure; Does anyone have the fuel press spec?

Is it possible for the TPS to be "half bad" and send out random timing advances to the computer?
This and any other suggestions would be appreciated!

Re: L250TXRR Slight missfire, intermittant loss of 300 rpm

Hoping somebody can give me some help??

Re: L250TXRR Slight missfire, intermittant loss of 300 rpm

You might try using a peak reading meter to monitor the out put voltages to the coils primary's to see if you are loosing spark to one or more plug.
Or try a inductive timing light moved to the different plug wires to see if you can detect the spark dropping. It will also let you monitor the timing while the RPM drops to see if it is moving around.

Maybe you can hook up a computer to this motor and get some information