What should the max rpm be on 16 24' boats?

[Kane]

I only have about 3 hrs on my 242x but I feel like the RPMs are a bit low. At first ride it was 7400 ish . by 3 hours it was about 7500-7600 ish. Should I expect to see this come up a bit after break in? Also what are others seeing?
Thanks
Mike

 

[robert843]

I think the 1.8's should pump around 7800 rpm. Could be that its new still or look for the start rating on your boat if its 3 stars it should be 7800 if its got the 4 star rating 7600 rpm might be it.

 

[swatski]

7800-7900 RPM is the max at which point the electronic rev limiter kicks in, most stock 1.8 pumps hit about 7700 at WOT under normal conditions, probably not much more. I don't know about CARB boats, I think @robert843 is right on.
Yours may loosen up, too, its only 3hrs.

Here is a rev limiter table:

 

[OperationROL]

Most I have ever gotton was around 7600.

 

[Kane]

Thanks for the info. hopefully it will loosen up a bit after its broken in.

 

[swatski]

I only have about 3 hrs on my 242x but I feel like the RPMs are a bit low. At first ride it was 7400 ish . by 3 hours it was about 7500-7600 ish. Should I expect to see this come up a bit after break in? Also what are others seeing?
Thanks
Mike

@Kane Any updates on that? Is this a 242x thing or all 2015/16s?
Thanks for any input.

 

[Kane]

So I'm at 16 hours and the RPMs are still 7500ish. My boat is not carbed so I was hoping to get closer to 7900-8000.....maybe it's still breaking in?

 

[haknslash]

So I'm at 16 hours and the RPMs are still 7500ish. My boat is not carbed so I was hoping to get closer to 7900-8000.....maybe it's still breaking in?

By CARB they are talking about the ultra low emissions, not a pair of carburetors. It's been noted on here by other members who have ultra low emission boats that the RPM is indeed lower than non-CARB model boats, around 7300 or so. Note that Yamaha ships both emission styles all across the country.

What is your top speed?

 

[Rod5]

We've got almost 30 hours on our 242x and max out around 7400 RPMs. With 10 people and full tank of gas max speed is 44, but with 2 people and less than half tank 48+ every time. I've noticed the air box intake hole seems small and restrictive, thinking about cutting some additional ports in the air box to see if it will breath any better and get a few more RPMs...

 

[Kane]

By CARB they are talking about the ultra low emissions, not a pair of carburetors. It's been noted on here by other members who have ultra low emission boats that the RPM is indeed lower than non-CARB model boats, around 7300 or so. Note that Yamaha ships both emission styles all across the country.

What is your top speed?

Yes correct, mine is a Non-CARB boat.....not carbureted. Lol

 

[seadude]

CARB = California Air Resource Board approved and outside of CA certain states apparently require a certain portion of boats sold to be 4 star compliant (at least that's what I've heard) so you may or may not get catalytic converter equipped motors. 7550 RPM is typically max on the 1.8L and should work out to 52 MPH on the 24 footers. Towers, bimini tops, weight and other factors will drag this down.

 

[Kane]

I'm on par with @Rod5. On average, 7450- 7500 max RPM and with 5 or more people in the boat, max speed is no more then 42-45. With myself and a passenger I've seen 48-51. Now if the wind is blowing with that Bimini, speed changes all over the place. I did see 7600+ once but 7450 seems to be the average.

 

[OperationROL]

Are you guys getting the same high readings on your starboard motor? My starboard is consistently 400 rpm lower than port.

 

[McMark]

Are you guys getting the same high readings on your starboard motor? My starboard is consistently 400 rpm lower than port.

That's because of uneven pump loading. Totally normal.

 

[OperationROL]

That's because of uneven pump loading. Totally normal.

That's why I ask. On my former 07 SX230, Yamaha used 2 different pitches for port and starboard to get the same RPMs out of each engine. Did that change? Are they now only using the same pitch for both sides?

 

[Rod5]

These e-series boats auto sync the RPMs perfectly so I haven't noticed any deltas between the motors. Also I have got the boat slightly airborne a time or two and could hear the RPMs increase ever so slightly to what I assume is 8000 so there is an opportunity to some how squeeze out just a tad more speed before the ecu limiter kicks in. Hence my idea of opening up the air box a bit...

 

[Kane]

These e-series boats auto sync the RPMs perfectly so I haven't noticed any deltas between the motors. Also I have got the boat slightly airborne a time or two and could hear the RPMs increase ever so slightly to what I assume is 8000 so there is an opportunity to some how squeeze out just a tad more speed before the ecu limiter kicks in. Hence my idea of opening up the air box a bit...

I'd love to know if this would make a difference. I wonder, for just testing, if you ran it with the cover off to see if it would make the rpms increase? I guess it may trigger a check engine light??

 

[Rod5]

You know that ran through my mind to as a quick test too. I'm figuring it will take a combination of box mod, more efficient filters, and removing the backfire ribbon screen to really see any improvement. But who knows maybe a simple test run without the covers will be a surprise...

 

[swatski]

I'd love to know if this would make a difference. I wonder, for just testing, if you ran it with the cover off to see if it would make the rpms increase? I guess it may trigger a check engine light??

I'm curious too. Pump revving up when unloaded does not mean much, it's a soft rev limiter, but I bet you would see real gains with ribbon delete. I don't remember now but they were changing the intake manifold on 2015 or 16 and then back again.
Removing the filter does not trigger any codes, but it probably will not do all that much.

 

[Mike Serra]

By CARB they are talking about the ultra low emissions, not a pair of carburetors. It's been noted on here by other members who have ultra low emission boats that the RPM is indeed lower than non-CARB model boats, around 7300 or so. Note that Yamaha ships both emission styles all across the country.

What is your top speed?

How can you tell if it is a CARB model?