Travelling at WOT

Just curious as to how to many guys with boats belt around at Wide Open Throttle when the conditions allow.

Myself, I'll sit on about 5100rpm when its flat but that's still 30 knots with a fully laden 6.1m ali being pushed by a 150 4 stroke yamaha.

The sweet spot for fuel economy though is around 4200-4500rpm.

Can't personally see the point in caning the motor at 6000rpm but I'm just wondering if I'm babying the motor to much. When I had a two stroke I used to crack it right open occasionally just to clean it out but with the modern four strokes I don't see the need.

Interested in peoples thoughts.

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Faulkner Family's picture

Posts: 18029

Date Joined: 11/03/08

i generally run my 350 chev

Wed, 2009-10-28 22:33

i generally run my 350 chev at around 3000 rpm which gives me around 22 to 23 knts in calmish waters using about 80ltrs for 55 to 60nm trip, occasionally on the way in i will open her up to 4000rpm at around 30knts which isnt too bad for a boat that weighs over 2tonne at 7mtrs but she tends to suck down the juice. dont like to punnish the boat or our boddies so im generally fairly easy going on the throttle, we all like to go fast but no real need. going too fast you could miss out on some nice ground to fish

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RUSS and SANDY. A family that fishes together stays together

Bluebonefamily's picture

Posts: 218

Date Joined: 15/08/09

We have the same motor and

Fri, 2009-10-30 18:38

We have the same motor and get about the same knts for rvs on our boat too.  We have never actually tested the motor's limits, there has never been a need.  We go as fast as can safely go in the conditions, usually enough to get up on the plane and cruise along.  Smile

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mako magic's picture

Posts: 5785

Date Joined: 03/08/05

nothing like a bit of WOT

Wed, 2009-10-28 22:56

nothing like a bit of WOT especially racing people back to the ramp lol

i normally drive to the conditions but dont like to hammer the boat and pound it

Rosco's picture

Posts: 454

Date Joined: 20/11/07

give it heaps

Wed, 2009-10-28 23:03

Give her heaps Big John! Pedal to the metal.I reckon a good squirt is great in glass conditions. With a 150 four stroke why wouldn't you!
You never baby your crewies so why baby your 4 stroke?
Rosco

big john's picture

Posts: 8751

Date Joined: 20/07/06

Watcha my shoulder

Wed, 2009-10-28 23:19

What are you talking about chaunce, you've had plenty of free rides.

Deliberately dropping a mackie on your shin so you couldn't pull the anchor, watcha my neck and who could forget the supposedly sore shoulder. Strange how it didn't hurt when you hooked those GT's in April!

LOL

When are you having the recon?

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Jigs available online in my web store!

Feral's picture

Posts: 1508

Date Joined: 01/11/06

i sit on about 4000rmp with

Wed, 2009-10-28 23:15

i sit on about 4000rmp with the chev moving me at 30+knots but only if conditions allow ... most of the time down here its 3000-3500 @25 knots ... no need to hammer it .. but im also running a brand new motor thats only done 20 hours .. every time i want to floor it i think of the 25k it cost me to install it :P

Faulkner Family's picture

Posts: 18029

Date Joined: 11/03/08

the chev 350 are a good

Wed, 2009-10-28 23:23

the chev 350 are a good motor, i get the best economy at around the 3000 to 3200 rpm in mine, at 3500 they just purr like a tiger on steroids. 

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kempy's picture

Posts: 810

Date Joined: 28/05/09

yes the chevs r a good

Thu, 2009-10-29 08:03

yes the chevs r a good engine that y u play bout 25k like us to have them

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gregk's picture

Posts: 169

Date Joined: 03/02/09

just cruze

Thu, 2009-10-29 05:47

i have 90 honda and sit on 5000 rpm when conditions allow no need to ring its neck to save 15 mins

Rick's picture

Posts: 1112

Date Joined: 22/12/06

Glass off

Thu, 2009-10-29 07:22

Nothing better than coming home on one of those glaas off days and open it right up.

Usually do it a couple of k's out from the ramp just to blow the cobwebs out,looking back at the wake............

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damo6230's picture

Posts: 2029

Date Joined: 07/06/08

usually cruise to the conditions

Thu, 2009-10-29 07:53

but if a glass off or on the river then i will give it full throttle just to blow the cobwebs.....but not for long

my best economy is around 3500-4200rpm

Cammos's picture

Posts: 606

Date Joined: 30/06/09

When I had the old 2 stroke

Thu, 2009-10-29 08:19

When I had the old 2 stroke Johno it was wide open as often as the hull would allow, but the stern drive needed to be nursed a bit too much for my liking.

I go fast as often as possible.

Brunno's picture

Posts: 22

Date Joined: 13/08/09

250hp Suzuki 4str

Thu, 2009-10-29 08:37

We usually cruise at between 20 and 22 knots depending on conditions. When we get glass off we normally bump that up to about 24knots. We figure that the motor isn't working as hard when there isn't any sea to deal with. But we always give it a blast to WOT for a few minutes if conditions allow. Just because it is part of the fun of owning a boat!

just dhu it's picture

Posts: 1081

Date Joined: 14/05/09

full noise

Thu, 2009-10-29 09:18

The modern four strokes are the same as your car engine, how often do you drive your car at maximum redline revs, the 2 stroke days you need to fang it ocasionaly to clean out the oil etc, my 6.1 alli + 150 yammy cruises nicely in good conditions 4.3k about 30 knots @ 1lt per NM , i drive the boat for the conditions and my crews safety and enjoyment , going flat out is okay but my view is things happen to quickly at high speed and the enjoyment soon sours when some one gets hurt or gears damaged. 20 to 24 knots is pretty good and comfortable on a long haul  

Simon C's picture

Posts: 801

Date Joined: 01/05/07

Agreed - flat out is one of

Thu, 2009-10-29 09:36

Agreed - flat out is one of the joys of owning a boat on glass off, that said, I pulled the 300 hour report on my 150etec and it showed I had used full throttle for about 1% of the time, so in reality that is not much. And I will bet every bit of that was coming back in on dusk at Exmouth trying to make the pub for dinner. Generally sit around the 4500rpm gives about 28knots and acceptable fuel economy - .8nm/l

uncle's picture

Posts: 9479

Date Joined: 10/02/07

crewies

Thu, 2009-10-29 09:53

right on John,that rosco will do whatever it takes, to get out of his duties,never actually pulled max.revs in the old girl,like coming home fast on a calm off.

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Bodie's picture

Posts: 3758

Date Joined: 05/11/07

my understand is 4 stks are

Thu, 2009-10-29 12:44

my understanding is 4 stks are built to run at high revs, and run better at high revs.

Saying that i dont go flat stick all that often. But will give her a squirt getting close to the ramps to be others in, especially if i can see a few boats coming in at once.

For me, around 4000-4100 gives me 25knots from the twin 140's. Fuel economy is approx 1.30/nm

Flat stick is up at around 5600, and can get 39knots on the river, but only about 34-35 on open ocean.

jersey's picture

Posts: 393

Date Joined: 12/06/08

Revs

Thu, 2009-10-29 14:04

I stick at between 38 and 4500rpm,I find this speed is the best for almost all weather conditions,as I have a lower back injury and I can walk off after a days boating,and I dont pound the shi iits out of my boat,I have used 5250/5500,rpm at the Mackerils with 5 on board and the sea like glass,but it was for a short burst to beat another boat with me,I find a great many boats can go real fast with the modern motors but the hull hitting the water at some high speeds is like a hammer being banged against the boat,I look at some and think Why?,Aluminum is a great product and is strong,but how many ali boats get cracks around the welds after a while,and the boat at the Mackerils was a walk around Whitley it was brand new for the trip but after a particularly rough bit of sea winds 23knots on the bow a lot of bits were loose on it.

Frank F's picture

Posts: 481

Date Joined: 17/03/09

Cats

Thu, 2009-10-29 17:26

Most of the time I sit on 23-26 knots which it is about 5000rpm, which my cat loves to ride at, but when it is like glass you can't resist giving it to her for a few minutes

wrassinator's picture

Posts: 554

Date Joined: 26/11/08

Maaaayte. 2 strokes thrive

Thu, 2009-10-29 19:16

Maaaayte. 2 strokes thrive in WOT !!! I need no excuse for WOT on my 40hp 2-stroke Mariner provided sea conditions permit ! always open her up for a good belting, but defer back down the rev range to 3/4 cruise after 5 mins or so. It blows the cobwebs outta the carbs, not to mention the oil crud from the cylinders ! lol

King-Prawn's picture

Posts: 56

Date Joined: 27/05/09

That Aint Living

Thu, 2009-10-29 19:27

90 hp 2 stroke Mercury. 18 foot Glass Fraser

 We usually come home from Rotto flat out. Can get 35 Knots in calm conditions.

 

# 1 on the water baby

 

wayneleech's picture

Posts: 362

Date Joined: 27/06/08

i have a optimax 90 on a

Thu, 2009-10-29 19:32

i have a optimax 90 on a 5.4m trailcraft profish - usually sit at 5000rpm which gets me 30-32knts

just dhu it's picture

Posts: 1081

Date Joined: 14/05/09

WOT

Fri, 2009-10-30 07:57

When i first bought my 6.10 trailcraft c/cab the motor was upgraded to a 175 hp Verada, 6000rpm 48 knots it was scary for my age, to many problems with the motor , i then changed to a 150 hp 4st yammy, some days i still wish i had the extra HP 

solly's picture

Posts: 375

Date Joined: 11/09/05

WOT+

Tue, 2009-11-10 16:53

250 etec is bloody awsome(scary too) at wot but for economy my I sit at 3500rpm averaging 23 to 25 knots with 19 inch prop. dont alway want to do 50 knots

solly

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Posts: 12

Date Joined: 28/11/09

On the way in

Mon, 2009-11-30 08:34

We have a 27' Chivers being pushed by a volva penta 200 turbo diesel. Usually at around 2500rpm we get 16-18 knts depending on winds and that gets us about 10litres an hour I'm pretty sure. We can crank it out to 25 knts at 3200rpm which is good for a 3Tonned glass boat.

wide open's picture

Posts: 444

Date Joined: 24/12/09

with our old 80hp mercury on fraser 19

Tue, 2010-01-12 15:20

we had 2 speeds, stop and full throtttle, it was ran at full throttle no matter how long the drive most of the time if conditions allow, had for 15-20 years, rebuild at ten another 10 please said the merc

tournament's picture

Posts: 376

Date Joined: 10/11/09

i open it up for a little

Tue, 2010-01-12 16:04

i open it up for a little bit but usually sit on about 4000 rpm