how long can you safely go wot?

[Nashport_native]

hello, I own a 1974 18ft reinell with either a 120 or 140 inboard engine (po had repowered it with a used engine, but wasnt sure with one)

this is my first boat i've had on the water. I know the engines are made to run wide open, feels kinda weird to just roll into the throttle and let it hang out at 4500rpm(thats all it will do when underway) I have gotten it up to 34mph once, but i just felt uncomfortable letting it sing like that for more than a min or so...

here is a pic of our new toy, I can see a v8 one coming our way next spring

 

[Blarney413]

Re: how long can you safely go wot?

Let'er rip!

 

[JustJason]

Re: how long can you safely go wot?

You can go until you run out of gas... but keep this in mind.... 90% of all the wear and tear on an engine and drive happens in the highest 10% of the operating RPM range.

 

[45Auto]

Re: how long can you safely go wot?

I know the engines are made to run wide open

They're made to run wide open just like your pickup truck engine is made to run wide open. No difference between a boat and truck motor. Don't know how old the motor or outdrive in your boat is, or what it's maintenance has been like. It's up to you, how long would you feel comfortable running your 20 or 30 year old pickup wide open?

 

[tschmidty]

Re: how long can you safely go wot?

Yeah your thinking is about right. You can obviously go WOT for a bit, but I usually settle down to around 3500 for cruising speed, 22-25 mph with a similar motor. Forces go up exponentially at higher rpms.

 

[haulnazz15]

Re: how long can you safely go wot?

Just because the engine is made to run up at WOT doesn't mean you should run it there all the time. That's a good way to eat through bearings with all of the load that a boat causes on the engine. I wouldn't run at WOT for more than 2 minutes myself, just as a precaution, but I guess if you plan on replacing the engine, hammer away all day.

 

[Alumarine]

Re: how long can you safely go wot?

Just remember that 4500 is around your maximum rpm.

 

[IES99]

Re: how long can you safely go wot?

I've found that 85-90% throttle will give nearly the speed of WOT, so rarely go there for more than a few seconds.

 

[jtmarten]

Re: how long can you safely go wot?

'Til just before the motor goes boom. 8^)
You should get about the same speed if you throttle down to 4000-4200rpm, and she'll be much happier there.

 

[Philster]

Re: how long can you safely go wot?

All things in moderation.

 

[Nashport_native]

Re: how long can you safely go wot?

thanks for all the replys guys. I dont like running it at 4500 anyway....4000 vs 4500 only gains 3 mph, not worth the extra wear and tear for the little gain in speed