Max Speed Issues

I have a 2008 240Sd and have experienced the same problem. I have a 350 Magnum 300HP bravo III

I have never gotten the speed over 39 mph. I did this on an early flat lake morning with the top down and my GPS as my evidence. Marine Max said they made an adjustment and that they had it up in the high 40"s ... I thought great, but NOT. I have been very unhappy with the power on my boat.
 
I have a 2008 240Sd and have experienced the same problem. I have a 350 Magnum 300HP bravo III

I have never gotten the speed over 39 mph. I did this on an early flat lake morning with the top down and my GPS as my evidence. Marine Max said they made an adjustment and that they had it up in the high 40"s ... I thought great, but NOT. I have been very unhappy with the power on my boat.

Wow thats very disappointing.

I know for a fact that there is definitely something wrong in your situation.

We upgraded from a 220 Sundeck with 260HP,
and on unbelievably flat days, we had it VERY close to 50.
 
I have a 2008 240Sd and have experienced the same problem. I have a 350 Magnum 300HP bravo III

I have never gotten the speed over 39 mph. I did this on an early flat lake morning with the top down and my GPS as my evidence. Marine Max said they made an adjustment and that they had it up in the high 40"s ... I thought great, but NOT. I have been very unhappy with the power on my boat.


Something needs adjusted... my non magnum 350 in my 2000 240SD gets me close to 48 ish via GPS early in the season prior to hull accumulation. (at least that is my memory, I'll need GPS it this weekend and report back.
 
I have a 2008 240Sd and have experienced the same problem. I have a 350 Magnum 300HP bravo III

I have never gotten the speed over 39 mph. I did this on an early flat lake morning with the top down and my GPS as my evidence. Marine Max said they made an adjustment and that they had it up in the high 40"s ... I thought great, but NOT. I have been very unhappy with the power on my boat.

That ain't right. We could hit a tad over 50 no problem. The 350 Mag is a great match for the 240 SD. If the bottom and running gear are clean, and MM won't help, call Mercury.
 
I was told today... new plugs and wires may help RPM's.... i'll let you know!

Not for a brand-new boat.

Anyway guys,
to report back...

I tried the suggestions of trimming the engine up quite a bit while on plane,
and I definitely noticed a difference. The conditions didn't allow for WOT, but when i was going about 45mph, I felt like there was a bit more juice to get me closer to 60 if the weather permitted.

Thanks for all the help,
Hope you get your 240SD running properly.

Brandon
 
There is one 240SD lurking around here that would beg to differ. Then again, it cost him a lot of squid.
 
There is one 240SD lurking around here that would beg to differ. Then again, it cost him a lot of squid.
:thumbsup::thumbsup::thumbsup: Sweet Boat and boy does it sound good, now where is that video :thumbsup::thumbsup::thumbsup:
 
Just another update...

I was out this evening, NO WIND,
and I got my 270SLX only up to 47.3 mph GPS.
I was running about 4700 RPMs.

This is definitely not right... I should be going 10+mph faster.

Does anyone know if 4700 RPMs seems right?
 
Bushaway,

I believe 4,400-4,800 rpm is the wide open throttle range for a 496 Mag. Check your manual. Looks like you are OK there. Also call you SR dealer and ask your sales guy to give you the top end range from his sales guide booklet. It's 43-47 mph for my boat. I can still get about 48 mph out of her with just me on board. My best speed ever was 50 on a cool Feb. day with full fuel and the bimini top removed. Also try googling your boat and top speed. Try checking Boating Magazine or Trailer Boat archives also. My best guess would have been about 50 with a 496 Mag.
 
Bushaway,

I believe 4,400-4,800 rpm is the wide open throttle range for a 496 Mag. Check your manual. Looks like you are OK there. Also call you SR dealer and ask your sales guy to give you the top end range from his sales guide booklet. It's 43-47 mph for my boat. I can still get about 48 mph out of her with just me on board. My best speed ever was 50 on a cool Feb. day with full fuel and the bimini top removed. Also try googling your boat and top speed. Try checking Boating Magazine or Trailer Boat archives also. My best guess would have been about 50 with a 496 Mag.

+1:thumbsup:

SeaRays are not known for their top end, they are known for their ride.:thumbsup:
 
Bushaway,

I believe 4,400-4,800 rpm is the wide open throttle range for a 496 Mag. Check your manual. Looks like you are OK there. Also call you SR dealer and ask your sales guy to give you the top end range from his sales guide booklet. It's 43-47 mph for my boat. I can still get about 48 mph out of her with just me on board. My best speed ever was 50 on a cool Feb. day with full fuel and the bimini top removed. Also try googling your boat and top speed. Try checking Boating Magazine or Trailer Boat archives also. My best guess would have been about 50 with a 496 Mag.

Yes, I understand the salesman said he got it up to 59mph gps,
so I will give him a call and see whatsup.

I appreciate your input,
because previously we had a 220SD and i had it up 48 no prob..

Thanks
 
I'd hand him the keys again and say do let's see you do that again with me on board. I'm joking to some degree, but I would ask the question. I would also want to have a look at his sales guide booklet.
 
I'd hand him the keys again and say do let's see you do that again with me on board. I'm joking to some degree, but I would ask the question. I would also want to have a look at his sales guide booklet.

Haha! :smt038

I appreciate your help...
No doubt about it, I will give him a call when I get a chance.

Saturday and Sunday look like boating weather for me!
 
No, but i think he should get somewhere around 52mph.

I think 60mph should be reachable in my 270 SLX with a 496MAG.
But we'll see...
270SLX WOT 4,800rpm at 50-54mph. Because of some of your questions on drive trim and trim tab position I wonder what kind of orientation you got with your boat. Did you get any?
 
just looked it up also . with a 6.2 mpi 320 hp it should do 42-46, and 8.1 375 hp 4800 rpm 50-54. and Ive had a few of these out and had them at 54 mph on gps. get that salesmant o take you for a ride!!! I wanna hear this one.
 

Forum statistics

Threads
112,942
Messages
1,422,701
Members
60,927
Latest member
Jaguar65
Back
Top