225 opti max

size matters · #1 05-26-2003, 09:26 PM

Anyone out there running a newer 23 classic? I have a 2001 with a 225 optimax. The boat came with a 17 mirage. I could only get 5100rpms. I just put on a 15x15 black max. It got me up to 5500 rpms, top speed on the GPS is 35mph with a full tank of fuel (140 gallons). Does this sound about right or should I be going faster? Thanks.

ltdan · #2 05-26-2003, 10:06 PM

DINGER, I'M NO PRO,BUT SOME HERE ARE. THAT 15"X15" SOUND'S WAY TOO SMALL. SHOULD BE TURNING A 19". MAYBE YOUR MOTOR IS TOO LOW? GO TO http//www.mercurymarine.com/prop PUT IN YOUR RIG'S INFO AND IT'LL GIVE YOU SOME SELECTION'S OF WHAT YOU SHOULD BE RUNNING. GOOD LUCK. LT DAN

SECF3114M73J · #3 05-27-2003, 12:06 AM

A friend just got a 225 opti installed on his '78 23 ft. center console and he ended up with a 17" Mirage, but he only holds 100 gal. fuel. A 19" Mirage was to much.

[ May 26, 2003, 11:09 PM: Message edited by: SECF3114M73J ]

barnacle · #4 05-27-2003, 07:55 AM

I do not know where a Mercury makes it hp at but it sounds right. As for the prop size it sounds about right. I can not see a 225 being able to swing a 19" prop on a 23ft boat. We would of tried a 15" first to see what rpm we ended up at.

Dunc · #5 05-27-2003, 10:37 AM

I'm running an '01 Seacraft and an '01 225 Opti. I'm turning a 17 mirage and can get it up to about 54-5500 rpms witha top speed of 47-48mph. I had concerns about the prop also but you really have to trim it out to reach those rpms and that trim level aint gonna cut it offshore in a chop. I think the boat reallly needs a 17 but a prop shop needs to do a little jiggering. Good luck

size matters · #6 05-27-2003, 12:25 PM

dunc. our dealer says our numbers are o.k. 34 ,35 mph sounds slow. our motor is set in the bottom bolt hole as low as it can go ???? how can i get more seep,topend.? thanks dinger.

JohnS · #7 05-27-2003, 02:45 PM

Dinger,
Sounds to me like your motor is set too low. When you are running, the cavitation plate on the motor should, ideally, run even with the water line as you are running. It is ok to be up a little more but, you may wind up with some cavitation. Also, Mirage props have the holes in them to aerate the prop. The older props did not but, I know the newer ones do. Personally, the props work much better with the plugs removed. You can remove one at a time and see how it works for you, each hull is different. I have a 225 Optimax running on my 23 Concept with a Mirage 21 with all the plugs removed. I had the motor running all the way up but dropped it down one set of holes due to cavitation in some slower following seas. Basically, unless I was hauling butt, it was cavitating. When I dropped it one set of holes, I lost about 4mph but the cavitation went away. Granted, my boat is lighter then yours, about 2600 dry but, you should be getting more from that Opti than you are.

John

Dunc · #8 05-27-2003, 03:03 PM

I agree, raise your engine one hole, that's where mine is. Interesting on the Mirage vent plugs--I hadn't thought of removing them to pick up a few more hundered rpms.

JohnS · #9 05-27-2003, 03:18 PM

Dunc,
Pulling those plugs makes a HUGE difference, not only in top end but in the holeshot too.

Try pulling one at a time until you find which
works best, as recommended by the dealer. Those Mirage props like to be aerated!!!

John

barnacle · #10 05-27-2003, 07:07 PM

The correct way to dial in this style prop is to change the size of the hole in the plug. They sell plugs that have different hole sizes. This has nothing to due with top rpm. The holes are for getting the rpm while getting onto plain by allowing the exhaust to pass tru the blades of the prop causing the rpms to climb fast. Past a certain rpm exhaust stops comming out of those holes.