How long should I run at WOT?

[Mrees]

I've got a 1997 19' Sea Ray with a 4.3L Merc and a 21" stainless prop. Just wondering how long I should run the engine at WOT. I never do. I believe WOT is supposed to be 4,400-4,800 but I try to keep it below 4,000. It seems to me that will be easier on the engine. Is that not true and I can run at 4,400 for extended periods and it will just burn more gas and not wear out the engine sooner? I've had the boat a little over a year. It runs great and we love it - just want it to last.

 

[Haut Medoc]

Re: How long should I run at WOT?

Theoretically, all day long.....
I don't do it for more than 5 minutes at a time......
I find it's best to find the boats/engines 'sweet spot', you'll get the best fuel economy, still get where you are goin' & your engine will last longer, IMO.....
Welcome to iboats, btw.....​

 

[Don S]

Re: How long should I run at WOT?

We had a couple of Charter fishing boats that ran 20-30 miles to a fishing spot, everyday they ran there and back. Full throttle most of the time.
Time is money they said. We agreed.
Every other year, we put in new engines for them.

 

[QC]

Re: How long should I run at WOT?

How many hours per day on those Don? Seems there is some real good longevity data there . . .

 

[Mrees]

Re: How long should I run at WOT?

"Time is $$"

Well I'm not in a hurry to get anywhere - I just like to go fast. But I don't want to go so fast I kill the engine

 

[Don S]

Re: How long should I run at WOT?

6 hours a day for 90 days (charter season) = 540 hours then they go 1/2 the next season (before they blow up) 270 hrs = 810.
But they don't get to go out Every day and some days the weather is too rough to make the long trip.
But lets just keep it at 810 hrs. Those (charter boats) that run at 3600 to 3800 are usually getting 3000+ hrs and usually repower during the winter, not overnight airfreighting engines in while loosing $1000 a day in lost charters.

 

[QC]

Re: How long should I run at WOT?

Now that's some real world/good data . . . thanks Don.

So imagine for a minute that you run 20% of your time at WOT (huge number for a pleasure boater). 20% of 810 (WOT life) is 162 Hours and then you need to add 80% of the 3000 for "cruise" type hours (3000 x .8 = 2400). So you end up with 2562 total hours (162 + 2400). Now, for fun, let's just cut it in half (1281). It is pretty hard to put 100 hours a year on a pleasure boat. There are exceptions, but most people do less than 50. With the 100 hour example, an engine could run almost 13 years before needing major engine work and this is at a conservative 50% of the also conservative 20% WOT example . . . My point? Worrying about engine life for a pleasure boater is silly. Worry about maintenance and forget it.

 

[Mrees]

Re: How long should I run at WOT?

I have about 350 hours on the boat. I'm not sure how it was treated befroe I got it at ~ 300 hrs but it sure seems to be in good shape. I tend to cruse around at 3,800 RPM cuz I don't like to go slow and am tired of those Bass boats blowing by me at 70mph. Thanks for the input. I guess I'll just cruise like I want and take good care of it and leave the rest up to God.