Hey guys new to the forum,

I bought an 88 223LS this spring with the 454 in it. I'm running the mirage plus 23P prop. Here is my issue. I'm running 4000RPM at about 50MPH(WOT). but after running the boat for a while it clears up and I come up to 45-4600RPM at about 60MPH. I will not touch the throttle at all, it will just open right up. Took a quick look under the hatch last night and notice the flame arrestor was pretty clogged up so I pulled it off cleaned it up with carb cleaner dried it and threw it back on. My problem still exists. took it out on the lake this morning and the same issue remains. Any clue what's going on? Almost seems like it is loading up on fuel then clears itself out for a bit and then loads up again. Any ideas would be great.

Thanks guys

This may be entirely off base... But are you trimming the boat? Most boats only get their last 4-500rpm's with the right trim setting.

Yup, trimmed out tabs up, just me in the boat. It's just so strange because its intermittent. The boat runs great when its not bogging down on me.

Change the fuel/water separator and any inline fuel filters you may have. Also check for a weak fuel line tank to fuel pump that may be collapsing.

How is the fuel quality?

Check the water separator.

I will check that out in the morning. Thanks guys. Fuel should be good. Just put in some fresh mid grade this morning.

so I replaced the fuel filters on it today(separator/Carb), problem is still there. Let the fuel that was in the separator settle out, no water in the fuel. any other ideas??

Could be a weak rubber fuel line that is collapsing under suction. something is restricting fuel delivery...you just have to sort out the reason.

Next time it does this immediately loosen the fuel cap....if you detect a rush of air you have a vacuum lock. Check the vent screen on the thru hull for obstruction.

Have you verified the choke is staying open?

Worn out plug wires have caused those symptoms for me in the past.