Organdonor

Pro Max 300X
Specifications
Propshaft Rated Horsepower (HP / kW): 300 / 224
Full Throttle RPM Range: 6100 - 6800
Cylinder/Configuration: V-6 (60 degree vee)
Displacement (CID/cc): 185 cu. In. (3032cc)
Bore & Stroke (in): 3.63 x 3.00
Bore & Stroke (mm): 92 x 76
Fuel Induction System: Electronic Fuel Injection
Ignition System: PCM 038 Digital Inductive
Charging System: 60-Amp (756 watt) with Voltage Regulator
Gear Ratio: 1.75:1 (TM) or (FM); 1.62:1 (SM)
Lubrication System: Electronic Mulitpoint
Fuel/Oil Ratio: Electronic Multipoint
Recommended Oil: Mercury Premium Plus (TC-W3)
Fuel Requirements: 91 octane (R + M/2) or 96 RON
Rotation: Left or Right Hand (SM)(FM) Right Hand (TM)
Shaft Length (inches): 20/25
Shaft Length (mm): 508/635
Weight (lbs / kg): 480/208 with 20" center section and Torque Master gearcase
Warranty: One-year limited warranty for recreational boating and three-year limited corrosion warranty. One-year limited Mercury Product Protection Plan available.
SmartCraft: Yes
Starting: Electric
Steering: Remote
Trim System: Power Trim




Features & Benefits

3.0L (185 CID) powerhead delivers unmatched power, performance, durability and reliability.

Electronic multipoint lubrication system delivers precise amounts of oil where and when it’s needed.

PCM 038 microprocessor provides maximum power and fuel economy.

Powerful 60-amp charging system operates electronic accessories without draining the battery.

Race-derived exhaust chest and tuner enhance power.

The SmartCraft™ Engine Guardian system monitors engine functions for early indications of problems that could lead to engine damage.

Torque Master and Fleet Master gearcases feature dual water pickups (mounted on the bullet and strut) for improved cooling, enhancing engine durability and overall performance.

Torque Master and Sport Master gearcases feature a heavy-duty propshaft for enhanced durability

Havasu Cig

Slingshot,

You have a pm.

macvtt

An AMT was in a recent boating magazine with the 300's. With the 300's watch the porpoising, the article said it did it almost all the time except at top speed which was about 100mph. I would definitely install a tunnel tab, it gets rid of the porpoising and helps the boat plane more level.

dreamboater

The 2.5's should provide a better balance being lighter on the rear, which should fly more level. However, the 300x has the warranty, and is supposed to be more advanced than the 2.5's. I would go with the 300x and if the porpois was that bad, try a tunnel tab like macvtt said.

Where is T2x, I am pretty sure he is running 2.5's on his Skater

Firewalker

The 2.5's have a warranty, the "RACE" motor does not, and the only differnce between the two is the rev limiter in the stock motor is 7750 and the race is 8250....and does not have a low water psi sensor n the ECU.
The 300X motor is not all that reliable, you WILL use the warranty.
The new 225X is so far showing to be a good peice.

I vote for the 2.5's

RT

rainmn

Out of curiosity, what's the biggest Merc O/B that doesn't require premium fuel? Probably not a concern if you're looking to build a 100 mph cat, but I was wondering for other reasons. (Center console.)
Don't mean to hijack the thread.

Firewalker

225HP 3.0 L

RT

T2x

I am.......But.....Here is my opinion....

If the cat is under 30 feet(28 Skater/30 AMT) go for the 300x's.... effective cruising speed will rise by about 10 mph......and top speed by about 5 over stock 2.5's.....
the 225's are considerably slower and rev less.......hence the increase in "dependability" (it is actually less self abuse)

If the boat is over 30 feet.....do not use outboards...... go for 525 hp's...and #6's.

Why?.....because everyone I know with a 32 and outboards...blows powerheads/lower units and center sections with awesome regularity......especially the 300x's.....

The reason?....I have no idea other than 32' cats are outboard eaters at 90+ mph in semi choppy water....The hulls apparently can take more than the engines will endure.

T2x

SLINGSHOT

I AM LOOKING TO CRUISE AT 65-75

dreamboater

I didnt want to say what firewalker said, but I have heard some unreliable issues with the 300x, dont have any personal experience so not sure. I have heard rumor on another sight of a 4 stroke turbo charged OB motor by merc. Havent heard much since, so that might have been just a rumor.