Pandora's box

16 years ago, I replaced the PTO seal on my stb, 12V71.
14 Years ago it started leaking,, again.

Been putting it off till it finally started pouring oil out.
F M

So, Big asp heat exchanger gets hoisted from over head. New seal AND cam shaft race get replaced.
So, while the hoses and plumbing are in my hands, lets pop the core, re-seal the weeping H/E gaskets and clean her up.
All looks good here.

Then, those new hose clamps I installed a few months ago look sad against those old ugly rubber hoses. If It's all apart, lets clean up those ugly rubber hoses.
Another quick call to my DD shop, another credit card wiped out, new blue silicone hoses on their way.

New Hoses installed last night and today.
All purged (dock side).
Hopefully tomorrow can leave the dock and get the girls warmed up.

Oh, poor lil sweet port engine, that's NEVER been an issue, is feeling lonely.

Ha, ordered extra gaskets and hose, she will be extra pretty soon also.

BTW, That one hose (pic post #5) is 3 7/8" ID.
Find that in blue silicone. It is available, just be prepared to B O A T*.

* Bend Over And Take-it
A great phrase our bud explained to us.
My credit cards and I have been using this phrase quite often since.

Power Take Off.

Back off the throttles.
You can de-tune but you will not accomplish a thing.

It takes HP to move the boat.
You want 10 kts thru the water, No matter what you do to those engines, The same HP and fuel consumption is required to move @ 10kts thru the water.

I used to push for 10kts over the bottom. Easy to DR with.
Sometimes less than 8kts thru the water, seems mostly faster than 8kts thru the water for that same 10kts over the bottom. With my luck and timing, up hill in both directions.
Ding, ding, ding totals up to KaChing$$

Hull speed is around 8Kts thru the water for us.
Lately, I've learned to slow down more and pull out the calculator when operating offshore @ 8 thru the water.

But, I can still fight an ugly inlet or run away from a storm.
Maintain your tune.

K I S S

Oh, ensure your air box drain check valves are working correctly. Here you can save some fuel.

Oh #2, the 550HP has different pistons.

Questions for you to compare rigs;
Your 12V71TI,, dry turbo, ZF clutch.
I'm 12V71TI,, dry turbo, TD clutch.
Yes, you have larger injectors and larger turbos..
I got the part numbers around here somewhere.

Have you figured hull speed for your ship?
Been doing it? That is the best it gets.
Do you ever open yours up to blow the gunk out?
What RPMs are you making?

Despite the price of fuel, I want another 100 HP.
This coming fall, I'm just going to bump up the injector heights a bit. Maybe find another 25HP @ 2000 RPM.

My partner has the 12V71TAs @ 900HP. I can out run him and it tics him off sometimes.
He is also 75' and could use a lil more umpha in the inlets.
He wants to go TIAs. @ 950+ HP

All this power and we mostly just do hull speed.

YES

Even naturals could use air coolers, just no way to plumb it in.
I often thought about just a 12V71A, Natural with after cooler. Not for performance, just to get that last air into the lung cooled off after the blowers. Maybe 25 more HP but lots more torque.
The colder the air, the more dense the air, always burns better.

With out changing the pistons, your always going to use the turbos and need to cool that air.

If your injectors are not leaking, your air box check valves are rite, your at your best tune.
De-tuning, changing prop pitch does nothing.
Remember, the same amount of HP moves the boat at same speed thru the water.
1/10 Gallon per HP per hour in salt water. 1/2 of that for turbos making boost.

Now, imagine this.
A pair of 4 lung JohnDeere 140 HP installed. If the boat weighed the same, you would burn near the same amount of fuel.
But these weigh a fraction of the Detroits. Yes, at hull speed you will see more MPG.
Not because the smaller engine loaded well (near max) but tons of less weight.

Humm,, Less weight..
No in-laws on board? That BBQ grill still in the laz?
Over weight dink on top?
Worn down props.

Oh, I sent a PM also.

Final questions (here);
Dialed up, hu? Explains the Allison clutches.
What color is your exhaust??
Do you smell skunk or diesel exhaust?
Does the exhaust burn your eyes?