wot
- Thread starter krb260
- Start date
My buddy has the exact same problem on his 2005 26' Sea ray. Max speed is 34mph ** 4500 rpms.
If you are doing less than 3600rpm, you are falling off plane bc you aren't going fast enough.
Another problem with the boat is how bad it leans going through the water no matter how it is trimmed or how much you mess with the tabs. It is really something you have to see to believe.
If you are doing less than 3600rpm, you are falling off plane bc you aren't going fast enough.
Another problem with the boat is how bad it leans going through the water no matter how it is trimmed or how much you mess with the tabs. It is really something you have to see to believe.
psychedelickat
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Have you thought about reversing the trim in inserts on the BIII to get more trim in?
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what top speed do get on your GPS ? what is the minimum speed you can stay on plane at ? how much HP do you have? are you sure your tabs are working ? the bow shoudl rise as you accelerate and drop some when you get on plane. once on plane the faster you go, the less tab you will need.
are you bumping into a rev limiter maybe ? if you're under propped and a rev limited kicks in at 4600, your speed will be lower... it's a long shot but...
are you bumping into a rev limiter maybe ? if you're under propped and a rev limited kicks in at 4600, your speed will be lower... it's a long shot but...
I just got the props back from a prop shop and they assured me they were a ok. they are 20pitch the smallest available for bravoIII. anyone with any info would be great. again I believe they are now using the 2.43:1 ratio not the 2.20:1 that I have.
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blouderback
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Why don't you answer our questions, maybe we can help?
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KRB…my boat is around 7300lbs (loaded) and about 2 foot shorter than yours. I have a 350mag (mpi) with 2.20 ratio B3 with 22p wheels. My motor will run up to 5100 and I can slow plane down to 32 –3300 without tabs, if the lake is flat. I think the specs on the 350mags with mpi is closer to 5200 at wot, at 4600 you have some to go.
Good luck
Niles
Good luck
Niles
krb,
I have the 6.2ltr engine installed with the b3 drive...same pitched props on my b3..I asked the very same question...the comment the dealer gave me was that they want these engines to spin tighter than a carbed engine....the mpi engine runs best at 4k rpm and mine will hit the rev limiter at 5280 rpm if I let it...I have the maxum 2700scr and although it's loaded with all the options...it does perform well..the dealer told me that if I was to run it at lower rpms, that this engine would bog down easier...hmmm...didn't make sense to me ..but that's the story they gave me....so...according to the dealer..your right there where your supposed to be by the factory's ideas....
I have the 6.2ltr engine installed with the b3 drive...same pitched props on my b3..I asked the very same question...the comment the dealer gave me was that they want these engines to spin tighter than a carbed engine....the mpi engine runs best at 4k rpm and mine will hit the rev limiter at 5280 rpm if I let it...I have the maxum 2700scr and although it's loaded with all the options...it does perform well..the dealer told me that if I was to run it at lower rpms, that this engine would bog down easier...hmmm...didn't make sense to me ..but that's the story they gave me....so...according to the dealer..your right there where your supposed to be by the factory's ideas....
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"top speed is 28-30mph depending on tide at 4600 wot planing speed is 22mph and the prop shop recomended against taking pitch out and said to try them again and get back to them"
something isnt' right here... you should get well over 30kts top speed with a sterndrive 26 footer. it should also stay on plane as low as 15/16kts. are those speeds GPS ?
something isnt' right here... you should get well over 30kts top speed with a sterndrive 26 footer. it should also stay on plane as low as 15/16kts. are those speeds GPS ?
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blouderback
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krb,
Did the prop shop do anything to the props? Why would they say "try them again"? Is your speed verified by GPS or are you using the very unreliable factory speedometer? You might want to get the tachometer checked, to make sure it's accurate.
Did the prop shop do anything to the props? Why would they say "try them again"? Is your speed verified by GPS or are you using the very unreliable factory speedometer? You might want to get the tachometer checked, to make sure it's accurate.
I gotta agree with Pascal on this one. I realize I have twins but mine planes at 17 mph although it's impossible to hold it on plane at that speed. To maintain I have to get up to 22 mph. anything less and it drops off. Then again, mine weighs 11700.
But the speed doesn't seem quite right either. at 4600 rpm's even with a single I would venture to guess that you should be going somewhere around 36-38 mph.
But the speed doesn't seem quite right either. at 4600 rpm's even with a single I would venture to guess that you should be going somewhere around 36-38 mph.
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blouderback
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Doing the math, your prop slip works out to like 25%. That's way too much. Something's not right, maybe with the accuracy of your numbers? I think we need to check the accuracy of the tach and verify the speed.
http://www.boatramp.com/prop_applet/PropAnalyzerAppletG.html
http://www.boatramp.com/prop_applet/PropAnalyzerAppletG.html
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well the tach may be suspect in trying to see if the engine is propped correctly but since the props are original and have been checked, regardless of the tach, the baot isn't performing.
assuming the speed quoted are GPS, i'd suspect the problem is with the engine not developping enough power.
tanq. my last boat, a heavy 37 footer with twin vee drive, coudl stay on plane at 16 kts with full tabs and a light load. i really dont' remember how low i could get my old 25 footer with single 260hp while staying on plane but it was well under 20kts.
i'm betting on engine performance issue in this case.
assuming the speed quoted are GPS, i'd suspect the problem is with the engine not developping enough power.
tanq. my last boat, a heavy 37 footer with twin vee drive, coudl stay on plane at 16 kts with full tabs and a light load. i really dont' remember how low i could get my old 25 footer with single 260hp while staying on plane but it was well under 20kts.
i'm betting on engine performance issue in this case.
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krb,
I have the same boat and engine, with the generator. WOT for me is about 4800 rpms and 38-39 mph. I cruise at 25 mph (GPS) turning 3650 rpms - no tabs but with the drive trimmed. Fuel burn (smartcraft) is 12.5 GPH average - a little higher with full tanks.
Once on plane, I can keep her on plane down to about 16-17 mph and about 3200-3300 rpm's with tabs down and the outdrive trimmed all the way down, assuming that conditions are calm or that I am heading into the seas.
One problem that I had at about 140 hours was a leak in one of the exhaust manifold gaskets. That caused a loss of power although not as severe as what you describe. Do you have an exhaust smell in the bilge when the engine has been running? A leaking gasket can also sometimes make a distinctive "ticking" sound.
Has this always been a problem or is it recent? Do you have benchmark numbers to compare to, by any chance? A lot of problems will cause an increase in fuel burn as one of your first clues.
The 350 is an EFI engine. Is the computer losing power causing it to unlearn your engines settings and run at a default setting? If I remember correctly, the default settings on the module would cause it to run rich. Not sure if that would cause your problem, though, and I am not a mechanic, and did not sleep in a Holiday Inn Express last night.
What is your engine temperature after it is warmed up?
Does it idle smoothly, or does it want to stall? Both warm and cold.
I have the same boat and engine, with the generator. WOT for me is about 4800 rpms and 38-39 mph. I cruise at 25 mph (GPS) turning 3650 rpms - no tabs but with the drive trimmed. Fuel burn (smartcraft) is 12.5 GPH average - a little higher with full tanks.
Once on plane, I can keep her on plane down to about 16-17 mph and about 3200-3300 rpm's with tabs down and the outdrive trimmed all the way down, assuming that conditions are calm or that I am heading into the seas.
One problem that I had at about 140 hours was a leak in one of the exhaust manifold gaskets. That caused a loss of power although not as severe as what you describe. Do you have an exhaust smell in the bilge when the engine has been running? A leaking gasket can also sometimes make a distinctive "ticking" sound.
Has this always been a problem or is it recent? Do you have benchmark numbers to compare to, by any chance? A lot of problems will cause an increase in fuel burn as one of your first clues.
The 350 is an EFI engine. Is the computer losing power causing it to unlearn your engines settings and run at a default setting? If I remember correctly, the default settings on the module would cause it to run rich. Not sure if that would cause your problem, though, and I am not a mechanic, and did not sleep in a Holiday Inn Express last night.
What is your engine temperature after it is warmed up?
Does it idle smoothly, or does it want to stall? Both warm and cold.
I had a 2000 - 260 Dancer with a 7.4 MPI - Bravo III. The boat ran great. I ran at 3200 RPM's at 28 MPH - GPS. The boat at WOT - was at around 4400 RPM's - which was around 42 MPH - Something is not right with your situation. The boat was a great running boat - your era 260 weighs in around 6200 lbs. 2005 - was the new hull design.
My props I believe were 22's or 24's - I can't remember. Something is not right -
My props I believe were 22's or 24's - I can't remember. Something is not right -
trying to answer all it idles smooth on all 8 ** 650 warm and never misses a beat hot or cold. No smells or noises from bilge (hatch open) idle or wot. It runs the same as it did from day one. The dealer keeps telling me this is the way its supposed to run. I just cant believe it,a new boat should not be such a challenge to keep going. again its a 2004 260da 7200lbs 17deg deadrise 350 mag 2.20:1 with 20pitch bravoIII. In 2005 they changed the deadrise to 21deg and use the new 2.43:1 ratio with the 20pitch props i believe