300 Mercury
 

How many hours are murcury 300 pro max's good for

Go ask on "screamandfly.com"

okiedokie

I dont think he was trying to be mean about that. To answer the question. Like anything, it depends on how you use the motors. I have a pair of 2000 300's on a 28 skater. I have 385 hours with no signs of the powerhead being tired. I have heard 800hrs, when left stock. Lower units on the other hand.....I have had all kinds of problems with those!

Anything major? After how many hrs?

They seemed pretty tired when i went around them.:eek:

For lower units, the issues have nothing to do with hours. I have broken a tooth off of a forward gear, replaced prop shaft seals and the rest of the seals many times, I have also broken 2 prop shafts, and in the process lost 2 propellors. Upgrading to the fat shafts will solve the prop shaft issue. Check your gear oil every other time out of so just to keep an eye on water in the gear case.

You may have walked around them in the parking lot....but thats about it. :D :D

same here the motors are great, but the lower units?????? well dreamboater already explained.........I have big shafts and never had any problems with them just seals...just check the oil every time and you'll be ok.

lets see my 300x let go at 44 hours put rod through the side of the block

I really doubt I was trying to disrespect the outboards when there are three 2.5's hanging on the back of my Skater! :D I am considering upgrading to the new 300xs's for dependability and more torque.

I have a question: I am building a 33 Oceanhawk, 300XS or 300 Verado?

300XS vs 300 Verado?
 

:drink: I am building a 33 Oceanhawk, which motor?
300XS or 300 Verado?

Thats a toss up. I do not know the torque curves for both engines. I would think the Verado would have more torque at a lower rpm due to the supercharger.

I had 140 hrs on my 300x's when I sold my boat...no problems to speak of and running very strong.
Gear cases were a a bit of a problem as mentioned. Mostly seals. I checked/changed oil every time out. I also snapped a fat shaft. Even on the fat shafts I would change them out every 50 to 75 hours on a cat. V's dont seem to have gearcase issues.

Tantrum,
On your AMT were you turning the props in or out? I am upgrading to fat shafts and would like to still turn the props in but I know that causes more stress on the shafts due to more stern lift.

I was spinning them out....the AMT didnt benefit either spinning in or out so I turned them out.
The problem with the cats is that the gearcase is out of the water most of the time. Because you are only useing the bottom half of the prop at speed the shaft is always flexing down. After enough flexing the prop shaft eventually break.
50-75 hrs is just the number I felt good with, Im sure you can get more but I spent alot of money on my props and didnt like throwing them away.
V bottoms never seemed to have the problems the cats do.

I would definatly upgrade to the fat shaft by the way. That would be money well spent I think.

How may hours where you getting from the small shafts before they broke?

u like those fat shafts huh.....

To scarab38's original question Ive heard 500+ but I dont think Ive ever run anything for 500hrs without breaking something :D

I think I would try the Verado in a bigger V set-up. If it can handle the the additional weight on the transom.
Two strokes IMO are for light, high rpm, WOT boats. Thats where they work best.

All you have to do is point the boat, Ill handle the rest :D
And if anyone is getting the shaft....Kenny will be the first to know about it :drink:

Hi Tantrum, Seem you have alot of experience w/OB. I have a "73 MAGNUM Sedan W/'98 300h.p. Mercs app. 60 hrs. on them,24-4blade Hyrdomotive props,Got 69.7 GPS so far. Usually cruise @3500,...........Should i have anything to worry about? Any segustions For more speed? Thanks, Michael

whos kenny?????:evilb: :evilb:

oh that guy with that slow ass skater.... i think i know him....

I have broken 2 in the last 30 hours or so. The last time was in a poker run with a lot of gas and weight in the boat. Recently I was running a set of 15x34 3 blades that Bblades did for me. Not really much gas but 4 passengers. I was only running about 50mph when it happened. I did not have any issues before I started turning the props in however. My boat is about 4 mph turning in.

My question about broken prop shafts would be what type of water do you run in??? I run on mostly smooth water ( under 2' chop) I shouldn't say anythng but I haven't broken one yet but I check my gear oil EVERY TIME I get back and change it about every 10 hours...
I would think if you run ruffer water where the boat leaves the water more it may happen more often??

I run twin worked 2.4's and 30 X 14.5 merc clevers

Maybe diameter also effects it????

High Life, The AMT was the only HP boat Ive owned with outboards so my experience is very limited.

The trick to outboards is set-up. Motor height, spacing, and good props.

As far as things to worry about......dont bend over in front of Stecz.

Hi Tantrum, Seem you have alot of experience w/OB. I have a "73 MAGNUM Sedan W/'98 300h.p. Mercs app. 60 hrs. on them,24-4blade Hyrdomotive props,Got 69.7 GPS so far. Usually cruise @3500,...........Should i have anything to worry about? Any segustions For more speed? Thanks, Michael

Rough water definatelly effects your prop shafts. I run on a river and its really not rough there either. Your prop size would also be quite a bit easier on your shafts. Running high motor height, turning them in on cats, and big props=very hard on 1" shafts.

I broke mine at about 50mph too. Funny thing was my boat only ran 50 for about ten minutes in its life.
3/4 gas, 2 people, 1-2 footers, just cruiseing, waiting :p for 2 other boats and SNAP, shiny new BBlade prop gone.
Brett did several sets of props for me, he does very nice work and gets then to you when he says he will. He has my business and my recomendation.

I ran the AMT pretty good regardless of water conditions, if it was going out, it was going.

Brett does an awesome job for sure! Where did the AMT go?

Ive also heard that 4 blades cad be easier on the gearcases because there is less chopping of the water.
My favorite props were 14.5x30 3 blade Mercs, 15x32 BBlade labed and 14.75x32 BBlade special sauce props. I had a set of 14.5x30 Ron Hill that I spent twice as much getting fixed as I did on the props....JUNK until they were fixed, but the 4 blades definately ran smoother. I ran them if I was worried about hitting something or the gearcases were taking in water.

Sold it to a guy here in Jersey (no cat experience). I talked to him last night and he hasnt run it yet. He is waiting on a boat lift and for me to come down and show him how to run it.

I wont be happy until I get another cat. :cool:

you don't have a set of 32's you'd sell?? I want to try a pair on my Skater?? i can turn the 30's pretty hard.

I dont, they went with the boat.
I only have a set of 30x3's left.

i broke the big shaft turning out 34s 3 blades rough water but i have heard of 4 300xs motors blown up, so far not sold on those things yet on a big fish boat i think i would go virados

Go and show what they are up to and you´ll get your respect.
It´s nice to blow by a 38+ft whatever with a Batboat or a 3C class Cat...
Even Reggie will get wrinkles from his (Big) forehead to his neck.

I have heard 2 stroke way out toque the 4 strokes

I've sold 13 of the new 300xs motors. They run the exact same top speed as the 300x's as long as you don't run over 112-113 mph. That's the speed that 34's will hit the 6400 rev limiter. At cruise speed, they get DOUBLE the gas mileage, and running hard, they still get about 60% more. We've only had a problem with one of them blowing up, and that was due to electrical problems that ended up getting replaced. I sell the 300xs with standard mids for $16,500. The LH offshore is $17,450 and the RH is $17,200. No tax outside Florida. They sell faster than I can get them though.

I'm putting a pair on a new 30ft Liberator cat now.

Maybe we need an outboard section here on OSO.