Running WOT

[apaseman]

Re: Running WOT

A couple of things:

1) The OP (trejac) was asking about a 4.3 Merc. Anything else just muddies this up and he/she has not returned . . . Some have touched on this, but I wanted to emphasize..

I'm sorry if asking about my motor is inappropriate in this thread. If it is forum policy to start a new thread around the same topic but specific to my motor, from now on I will do that. I just assumed it was on the same topic.

 

[26aftcab454]

Re: Running WOT

Do you drive your truck at 5k for ten minutes or longer?

Will it blow apart, no it shouldn't, but you are taking time away from motor life rapidly.[/QUOTE]

I had read that GM( and I'm sure the others ) say you can run at WOT -rev limiter--without damage- yeah but for how long? you do not floor it every where all the time do ya? unless you run NASCAR -8500RPM! Motorcycles run alot higher.
I watched a documentary on the testing of the Harley VRod-they ran it WOT for 30 min then let it idle for 30 min. at 100F. degrees. Of course the rider got off and sat in front of the A/C!
Half the fun of owning a bass boat is running 70+mph across the lake when no one is out and the water is slicker than snot!
I run my boat WOT 4600RPM once and awhile for a few minutes to make sure every thing is good.I mostly cruise mostly 3200 To 4000RPM. I think my motor is happiest at 3500RPM

 

[QC]

Re: Running WOT

No problem apaseman, just trying to help these threads stay clear. What happens is that the info gets mixed up between the different engines.

Oh, and by the way gang, engine stuff should probably be in the appropriate engine or prop forum, but this was about operation so I left it.

 

[ovrrdrive]

Re: Running WOT

A couple of things:

1) The OP (trejac) was asking about a 4.3 Merc. Anything else just muddies this up and he/she has not returned . . . Some have touched on this, but I wanted to emphasize.

2) I keep seeing references to redline. This is not a redline discussion. To be precise, it is about WOT RPM range which is where you need to be to be propped correctly. Redline refers to vehicles with transmissions that can exceed safe RPM levels. WOT range is a good thing . . . Some have touched on this, but I wanted to emphasize.

3) WOT range is specific to year, make model etc. All else is speculation . . . Some have touched on this, but I wanted to emphasize.

I disagree with this... Here's the wiki for redline and a closer definition to what my understanding of it is. An engine's redline has nothing to do with over revs or a transmission.

Redline refers to the maximum engine speed at which an internal combustion engine or traction motor and its components are designed to operate without causing damage to the components themselves or other parts of the engine

Hence when I say I redline my opti I'm saying I run it up to the rev limiter which is the maximum recommended rpm from the manufacturer for the engine to be safely run.

http://en.wikipedia.org/wiki/Redline

 

[JoLin]

Re: Running WOT

I like to run mine at WOT in the driveway without muffs



I don't run at high speed very often. Water conditions here seldom permit it anyway. I will try to do so on accasion just to make sure I don't have any ignition or fuel delivery problems.

 

[Philster]

Re: Running WOT

Apples and oranges everywhere!!!

Can you run at WOT for 'long periods of time'. Yes. Should you: It depends.

However, you should create a thread about YOUR engine and give all the details.

Wow... running a two-stroke outboard versus an I/O at WOT.

Some guy runs WOT for 30 to 45 mins and has clocked 1600 hours.

For purposes of this discussion, I will say this:

Numerous things you do will not guarantee anything, but these things you do will increase the likelihood of something happening.

If you run at WOT for long periods of time, you merely are at increased risk for early engine wear, bearing failure, etc. Does it guarantee it? NO.

Run more conservatively and you are at a decreased risk for trouble. Does it guarantee a perfect engine? No.

If you look at the various classifications of use, running at high RPM and extended periods of full throttle increase the risk of various things. Head over to the I/O section and read about bearing failure in high performance engines. See, the engines are similar, but the users of such engines tend to run at WOT a lot more. Do they all watch their engines blow up? NO. But more of them do.

 

[180shabah]

Re: Running WOT

ovrrdrive - nobody cares what the definition gods at wiki have to say about the redline (max speed that can be run INTERMITTANTLY) of some generic, fictitious IC engine. It is irrelevent. The OP has a 4.34 I/O and as asuch does not have a single redline spec, but rather a WOT range. If setup properly, his WOT rpm will naturally fall into this range and NOT hit an electronic rev limiter(if even equiped)

Yes, current I/O's are equiped with rev limiters to protect the engine from stuoid people, but this should not be confused with a redine rating. They are always programmed to kick in at an RPM that is higher than the rated spec. Usually right before valve float on an I/O, but other considerations are, drive rating, and catastrophic failure of the rotating assy.

If you are running you engine up to the revlimiter, then you are underpropped and flirting with disaster, but hey, it is your wallet.

 

[trejac]

Re: Running WOT

A couple of things:

1) The OP (trejac) was asking about a 4.3 Merc. Anything else just muddies this up and he/she has not returned . . . Some have touched on this, but I wanted to emphasize.

QC thanks for the response. Sorry it has taken so long to get back but I was working on my boat trailer last night until I was so tired I passed out.

I here what everyone is saying and opening it up alittle is just what I will do. I normally cruise at a comfortable speed for the lake and the conditions so WOT has never been such a big deal. Especially since I do not know what pitch is on the prop.

Now when I rode my 955I, I was wide open all the time (130MPH +). I guess I'm just more confident on two wheels

 

[trejac]

Re: Running WOT

Everyone, sorry for using the term redline it seems to have caused some conflict on the forum!!!!!

I undestand that I should have used the term WOT range. I will be more careful next post.:redface:

 

[Summer Fun]

Re: Running WOT

This will be the last thing I say on this.
Boat engine were built to take it. If your engine blows apart from running it at WOT for more than 30mins ??
It was JUNK to begin no matter what make it is !!.

PS, I'll see if I can find the pic of us coming from the other end of the 21mi long lake at WOT.

Edit: I found it.

 

[QC]

Re: Running WOT

All we have in an online forum is words . . . I don't mean to be a stickler or a righteous pain in the arse, but there is no way we can all make intelligent decisions about technical issues if clarity is absent.

I happen to agree with the wiki definition: "Redline refers to the maximum engine speed at which an internal combustion engine or traction motor and its components are designed to operate without causing damage to the components themselves or other parts of the engine" and I believe it is consistent with my point that it is a necessary piece of info if you are driving a vehicle with a transmission that will allow you to exceed that number.

A marine engine, on the other hand, is "governed" by load and cannot reach "redline" if it is propped in the WOT range as it should be. There, I used both in the same sentence and kinda illustrates the difference . . .

 

[haulnazz15]

Re: Running WOT

I don't run any boat at WOT for more than 30 seconds or so. Even with the outboards I only run it there for that 30 seconds, then back it off 500 rpm or so. The difference in speed isn't that much and the 1 minute of extra time it takes to get to a fishing spot isn't going to help me out since I don't tournament fish.

Same with the 5.8L I/O, WOT for 30 seconds or so if I am on glass water and want to "blow the cobwebs out", but after that it's back below 4000rpms.

 

[642mx]

Re: Running WOT

I've got a 4.3L, so I'll chime in.

The 4.3L Merc is a tough engine. Its built for abuse and you find very few of them that has spun a bearing or snapped a rod from mis-treatment.

With that said, I don't try to abuse mine, but it happens Everytime I'm on the water, it gets opened up anywhere from 1 minute to 10.

Last summer I was out-running an approaching storm and had it pinned for 1 hour running back to the dock. It was fully trimmed and turning 4900 rpms.... for 1 HOUR! It never missed a beat and I figured the risk of hurting the engine was worth the reward (tornado warnings, hail & high winds was in this storm). I made it back, loaded her up and even got the cover on before the storm hit. It was hot, and it was burning some gas, but it was fun!

I also ran it 72 miles at 4300 rpms coming back from a yearly run we do on the Ohio river. It did get about 20 minutes of rest while we locked thru a dam, but it got ran really hard that day with several WOT runs too.

You can run them hard, just keep the oil clean and use a drive shower to keep the temps down on your lower unit.

 

[180shabah]

Re: Running WOT

A marine engine, on the other hand, is "governed" by load and cannot reach "redline" if it is propped in the WOT range as it should be. There, I used both in the same sentence and kinda illustrates the difference . . .

That is what I was try to clear up. You said it even clearer.

 

[ovrrdrive]

Re: Running WOT

Ok so who's going to jump on him for calling it pinned and opened up instead of WOT?

Bunch of sticklers around here...

 

[642mx]

Re: Running WOT

Ok so who's going to jump on him for calling it pinned and opened up instead of WOT?

Bunch of sticklers around here...

hahahaha... You need thick skin to be on this website....

I figured I would get flamed for running fast and putting everybodies lives in danger...lol

 

[ovrrdrive]

Re: Running WOT

hahahaha... You need thick skin to on this website....

I figured I would get flamed for running fast and putting everybodies lives in danger...lol

Actually this is a very tame and easy going group except for about 3 individuals (you know who you are) that seem to constantly try to **** in everyone's cornflakes. I hang out here because it's laid back. Some of the other places Ipost are quite the opposite. If you post there you better have sources and links to back up what you're saying or 10 of them will eat your lunch.

The mods could do 5 minutes of housekeeping around here and it would be like Disneyland.

 

[Summer Fun]

Re: Running WOT

I think you guys have girlish boats that can't take it. . .