I recently purchased a 1990 31' Wellcraft Scarab Excel w/twin 454 mag Bravo 1's. Currently, the engines only max out at around 4100 RPM. The drives have 23" Mirage 3-blade stainless props. My two questions are 1)What is the correct WOT for a 454 mag and 2) Is it possible that my prop size may be too large?

Also, what are the other possibilities as to why my engines are only hitting 4100 RPM? To me, the prop size doesn't seem as though it's too large for this boat/engines, but maybe I'm wrong??? Is there any sort of rev limiters that could somehow be set too low??

Go to the prop section and get in touch with Throttle Up they will get you where you need to be.

When my 525 was only getting about 4000 RPM it turned out i had a bent valve and a leaky head.

24Baja,
Check your rev.limiters if you have them,make sure their both set the same probably 5200. next check an make sure the
throttles are pulling the carbs. all the way open unless you have fuel injection. You stated you have 23 in. mirage props. but what pitch? Check with your local prop. shop they should help you out as to what dia. an pitch you should be running.

I have a friend with a 89 scarab panther with the I think 365's he turns them at 4600 with 23's. 23" is the pitch.

Oh yeah! welcome to the SCARAB Family!

I'd have to agree that those props are right around where you need to be. There must be something else going on. I've got a 31 sonic with the mags and the 23's are the ticket. I assume your trimming it out correctly and not running drives all the way in. Agree, check throttle pull range on motors.