Information on 2001 Pro Max 300X

[WILDMAN]

2001 is a 300x. With twins you will be lucky to get 1-1.25 mpg

[wannabee]

2001 is a 300x. With twins you will be lucky to get 1-1.25 mpg

I am sure it's a Pro Max 300X - I think the decals designated a model for Long shaft hence the X.

I will find out when I see he boat and get the model #'s and serial numbers. I agree about the gas. Iam used to that we Have a pair of Yamaha OX66 on the back of a 34 ft Intrepid and we are used to 1 mpg

[vnemous]

the x in the decal has nothing to do with the length of the motor which would be L=20", XL=25" and XXL=30".

[Hot Shot Merc]

The X doesn't designate shaft length.

The X model

Is higher compression than the regular promax
It has a different intake plenum.
Its non painted block unlike the promax black painted block.
It has a totally different ignition system than the promax like stated already.The X has a side mounted computer and the promax has two computers mounted on the back of the block. Neither is opti with compressor.

Here are pics of the 300X

[Hot Shot Merc]

And here is a 300 Promax. Note the computers on the back,the black block and different intake

[vnemous]

I found this pretty interesting reading a Mercury Service Bullintin for 2001 300x.

Model 300X Pro Max 3.0L
COMPRESSION
Using a fully charged battery, throttle
shutters wide open and cylinder
block warm
110-115 psi (758-793 kPa)
Variance between cylinders should not
exceed 15 psi (103 kPa)
COMPRESSION
RATIO
6.2:1
CYLINDER HEAD
CHAMBER
VOLUME
61 cc

[RiChavis]

Correct 300X has the down draft intake and the newer one has,1 box on the side .

[vnemous]

the newer one has,1 box on the side .

300x was made from 2001 to 2005 and they all only had one computer.

[JPEROG]

An X makes 330 horsepower out of the box and is worth about 1 1/2 times what standard 300 promax brings today. If they are true X motors you have a decent amount of value in the motors. They updated the electronics in 2003 I believe.

Joe

[RiChavis]

I was also told in 2005 ,the last year they made them .They got the electronics right and it was putting out the most HP that year ?

[Hot Shot Merc]

I found this pretty interesting reading a Mercury Service Bullintin for 2001 300x.

Model 300X Pro Max 3.0L
COMPRESSION
Using a fully charged battery, throttle
shutters wide open and cylinder
block warm
110-115 psi (758-793 kPa)
Variance between cylinders should not
exceed 15 psi (103 kPa)
COMPRESSION
RATIO
6.2:1
CYLINDER HEAD
CHAMBER
VOLUME
61 cc

I thought the X had around 140 lbs compression?

[vnemous]

My point, now where is my compression tester

[Hot Shot Merc]

Both 3.0 ltr 300's are Promax.

The Promax X is a Promax with Extras. Higher rev limit (7,000),electronics,intake,more compression,HP etc.

The X cowls say Promax 300X instead of just Promax.

[Brad Zastrow]

Real simple. 300X has intake with throttle body at the top. 300 promax block and heads are painted black. 300x is anodized gold (sort of).

300X is to date the most powerful two stroke Merc made. Highest horsepower at close to actual 330. The 300 Promax made 280 and is a dog compared to the 300X. The 300XS is the latest version that makes a true 300hp and give better gas mileage. In my book who care how much gas they use I want the power and higher rpm.

[wannabee]

Guys thanks- I will try and check under one of the cowlings.