WOT, how long is too long to keep 'er pinned?

[BonairII]

Re: WOT, how long is too long to keep 'er pinned?

Totally unnecessary with modern fuel injected cars.

Why do you think that? Plenty of older fuel injected vehicles go into the shop for clogged injector(s).

 

[WetRiverRat]

Re: WOT, how long is too long to keep 'er pinned?

If he can stand WOT on that, he has got one good engine there I gotta say. Seems like he is due early for maintanence and repairs though.

 

[UncleWillie]

Re: WOT, how long is too long to keep 'er pinned?

Why do you think that? Plenty of older fuel injected vehicles go into the shop for clogged injector(s).

And running them at WOT or at idle has nothing to do with why they got clogged!

 

[roscoe]

Re: WOT, how long is too long to keep 'er pinned?

The bottom line is that every stroke of the piston and rings causes wear. Ever revolution of the crank causes wear to the main bearings, etc. Yes the wear is almost unmeasurable but wear is cumulative in nature so there is a finite limit to how many revolutions the engine can make before it is worn to an unacceptable level.

An engine that is ran at 5,500 RPM for 500 hours is going to show more wear than an engine ran at 3,000 RPM for the same amount of time. Now with that said, we (most of us) don't run our boat engines to see if we can make them last forever and lots of guys look at it as the engine will need to be rebuilt at some point so they may as well enjoy it fully.

My take, the real problem comes in when these engines are ran WOT all the time but don't get the proper maintenance. Run an engine at WOT that is low on oil or has dirty oil, low oil pressure, etc. and it won't last long at all. Same for keeping it tuned up, proper fuel flow so it never runs lean, etc. Keep the water pump in top shape and all water passages flowing properly.

But you would need to run over 900 hours at 3000 rpm to cover the same distance.

 

[roscoe]

Re: WOT, how long is too long to keep 'er pinned?

Direct quote from a 2010 Mercruiser O&M Manual:

After Break‑In Period
To help extend the life of your Mercury MerCruiser power package, follow these recommendations:
? Ensure that propeller allows the engine to operate at or near the top of the specified WOT RPM range. Refer to
Specifications and Maintenance.
? Operate the engine at 3/4 throttle or lower. Refrain from prolonged operation at wide‑open‑throttle RPM.

Follows some common sense IMO - so i suppose i will heed it and my common sense.

Define prolonged.

 

[QC]

Re: WOT, how long is too long to keep 'er pinned?

You might as well be asking what is the best type of oil to use. You will never get a consensus on this question.

Yup.

 

[lncoop]

Re: WOT, how long is too long to keep 'er pinned?

You might as well be asking what is the best type of oil to use. You will never get a consensus on this question.

I use dyno when running WOT and synthetic when cruising. The admiral is constantly complaining about having to stop and change tanks.

 

[Vankaye]

Re: WOT, how long is too long to keep 'er pinned?

That's nothin' man... I'm such a huge douche that I run my boat at WOT for 3-4 hours at a time on the trailer with ears on, in the middle of the night, when I'm drunk. And naked. And hopping up and down on a pogo stick.

 

[lncoop]

Re: WOT, how long is too long to keep 'er pinned?

That's nothin' man... I'm such a huge douche that I run my boat at WOT for 3-4 hours at a time on the trailer with ears on, in the middle of the night, when I'm drunk. And naked. And hopping up and down on a pogo stick.

With the ears on? Phhhht. Amateur.

 

[zlman1970]

Re: WOT, how long is too long to keep 'er pinned?

That's nothin' man... I'm such a huge douche that I run my boat at WOT for 3-4 hours at a time on the trailer with ears on, in the middle of the night, when I'm drunk. And naked. And hopping up and down on a pogo stick.

I should move next door, we'd get along great!

 

[Vegas Naturist]

Re: WOT, how long is too long to keep 'er pinned?

...reminds me of having new lookouts scan the sky looking for "GU-11's"!

LOL, In the Air Force, we used to send the newbies down to all the shops on the flightline looking for a can of Prop Wash.

John

And thank you for your service!

 

[lncoop]

Re: WOT, how long is too long to keep 'er pinned?

I should move next door, we'd get along great!

Don't think so. My POA doesn't allow pogo sticks.

 

[BoatDrinksQ5]

Re: WOT, how long is too long to keep 'er pinned?

Define prolonged.

HA - no kidding.

In the break in period it mentions '5 minutes' as being a key indicator (iirc) - so I would say somewhere between 5minutes and a LONG time - haha!!!


Where did that NOS thread in NonRepair i was reading go to....

 

[UncleWillie]

Re: WOT, how long is too long to keep 'er pinned?

FYI one thing I've learned is my motor is significantly less 'efficient' at high RPMs ... Anybody else experience this phenomena?

It depends on how you define EFFICIENCY.
As your RPMs increase the boat speed will increase, but not linearly proportionally.

As your RPMs increase .....
Your Horse Power (hp) increases. (Up to a point)
Your Miles per hour (mph) increases.
Your Gallons per Hour (gph) increases.
Your Miles per Gallon (mpg) Decreases.
And your Gallons per hour per horsepower gph/hp Decreases.

The gph/hp is the efficiency of the motor at converting fuel to work and will always peak at the peak of the Torque-Horsepower (TH)Curve.
The gph/hp data (AKA Basic Specific Fuel Consumption) for your engine is not one you will likely be able to get from the manufacturer.

The peak of the TH curve is the recommended WOT setting quoted by the engine manufacturer.
There is nothing to be gained by by going above it.
You will make LESS horsepower, burn MORE fuel and go SLOWER.

Having said all that, I understand that what you really meant was, "My BOAT is significantly less 'efficient' at high RPMs." Meaning your mpg is lower. Which is completely true!
Everyone will experience this. It is one of those laws of physics that you can not get around.

Your mpg is usually at MAX at dead idle with a second peak just above Planning speed.
Going faster gets you there sooner, but lowers the distance you can go.