Outlaw2005

I picked up a new to me 2005 Outlaw 23 SST and have had it out a few times this year. I’m curious to what others are seeing for top speeds and rpm’s at WOT. My boat has the 6.2l with a 23p mirage prop. I’m getting 48mph at 4550 rpm (throttle all the way ahead) with full tank of fuel, my wife and I, and in light chop. I have played with the trim and tabs and was able to dial it in and to get the results listed above. The engine has had a new distributer cap, plugs, wires, and fuel tank check valve installed prior to this boating season. The engine runs great (no bog, missing, or backfiring). Is this setup about right or am I low on rpm’s and speed?

bajaman

Something is WAY off...that calculates out to 27% prop slip...two to three times what you SHOULD have. Are you getting it trimmed up/out well?

Outlaw2005

Sorry, it’s a 21p not a 23p. I just went and double checked. Yes, I’ve tried many different trim settings and that’s the best I can do. Thanks for your thoughts.

bajaman

That is still 20.4 slip ratio...way too high still.
What outdrive, and what ratio on the outdrive?

The older 23' - 24' Outlaws, which I am more familiar with having had friends with them, have a 24 degree deadrise and are about a 4,000 pound hull...24' long with 96" beam. My 252 Islander is 25'6" long, 100" beam, and 4400 pounds dry by comparison. I run a 4 blade Revolution 4 prop, 21" pitch, can spin it to 4500 - 4600, and hit 53 - 54 mph.

The 6.2 comes in 300 hp and 350 hp versions...which is yours? Both are rated to spin 5400 rpm...it's a pretty cool engine! You may simply be over-propped. IF you can spin a 19" @ 5400, you'll be tickling 60 mph.

I'd check everything including a spun prop hub.

Outlaw2005

The engine I have is a 320hp 6.2l with a 1.5 drive ratio. I just confirmed this with Mercury. WOT setting is 4800-5200 rpm. Do you guys suggest I try a different prop before I dive deeper into engine performance specs such as compression testing and fuel pressure?

bajaman

Ah, okay...one of the older 6.2 versions, cool. Well, there are a host of things you can check to see if the engine is making proper power, compression amongst those. Have you had the ECU scanned to see if there are any does of any sort? A scan will reveal MANY things like injector duty cycle, timing, temps...all good to know. But if you are making full power then yeah...something is still off. You SHOULD be able to spin a 21" Mirage close to or at the recommended WOT rpms. Your boat should be faster than mine, put it that way.

JaayTeee

Have you checked if the throttle plate is actually at wide open when the throttle lever is?

I would think it would run in the 50’s

Outlaw2005

I haven’t had the ecu scanned yet. It’s odd that it runs so smoothly thru out the power band. I will check the throttle plate/linkage tomorrow. Would very small dings or curls in the cup of the prop cause this much lack in speed or rpm? The previous owner must have hit something. Thanks for all the ideas.

bajaman

No...small dings and dents really don't affect things that much...remember it is the 'front' of the prop (facing the boat) that does the work. Big dents in the edges of the blades or chunks missing can cause problems, but not like you might think.
I would see what a scan might reveal on the health of the engine, check the throttle plate as suggested, etc. You have all the classic signs of being over-propped, you really need to be able to pull the manufacturer's rated WOT rpm.

Outlaw2005

I have a call into the local marine repair shop to get the scanner hooked up. I’m also going to order a 19p to try (I need a spare prop anyway). Thanks for the help. I’ll post again when I try the 19 or get the engine scanned.