I just taken my boat[SX190/150 Yamaha] to the lake and was not happy with the results. I was at 5800RPM's and only going 48.2 MPH. The boat was serviced last year. I've owned it for five years and probably less than 150 hours at the most on the motor. Before I had GPS when the boat was new I was 67MPH speedo. Now GPS is saying something is not right. I need advice to get the speed back to normal.
Most GPS unit are very heavy and also have poor aerodynamic properties. These two designs characterstics typically result in a reducton of speed.
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Yamaha 250 SHO
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A little unknown secret is????? SPEEDO's LYE
Sorry, I've seen much higher speeds on the speedo than I've evers seen on my gps.
Yes you are correct, speedo's do lie. I didn't know the difference when I first started boating. I'm sure that I should be going faster than 48mph @5800RPM's.
If your tach is right then something is up with your prop. My 150 spins a 25" at 5800rpm for about 62mph
Like the others said you can go by the speedo. Was that 48 MPH per GPS or speedo on dash? If it's on the dash there is a possiblity that the speedo hole is partially stopped up on the lower unit and is not allowing full water flow in it and inturn will not show more speed on the dash. Plus these boats will not run 67 MPH.
YOU are not entitled to what I have earned!!!!!
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You don't say which prop you are running but I will guess its a 23p. If you are actually turning it 5800 rpm, which would be about right, then you have to be going faster than 48 mph. Maybe your gps unit is messed up. Can you borrow a handheld gps from someone and try it again?
wow, something doesnt sound right. Depending on the prop and setup at 5800 rpms that boat should at least be running 57-58 mph if not a little faster. My first question is are you trimming it up? if so are you possibly way over trimming?? Wonder if youre hub is slipping?? Know anyone with a spare prop like yours to try?
It is from the GPS. No more water time than the boat has had in the past, it should be alot faster. I'll use a hand-held gps next trip. Thanks for the tips. Trimming the motor about 3/4 full trim + a little.
Went back to the lake today with hand held GPS and it read the same as mounted GPS, only .1 or .2 difference. I made it to 55 at 6600 rpms and started to chine walk. It makes me think the tach is wrong because I have more petal to press. It started to go over 7000 rpm's and backed down. When I firsrt got the boat dealer said it wouldn't go pass 6000 rpm's or it would shut off like a kill switch. Aftr the first 10 hr. inspection I told him about getting near 7000 and he told me no way. I don't know if he knows what he is talking about or the tach is wrong. It has been that way from day one. Anyone have anymore suggestions?
if you keep running it at 7k, its gonna blow up!
Make them take it out with you for a text drive to see what your talking about!
2016 Ranger 520c - Mercury 250 Pro XS - Lowrance Electronics - Hot Foot - Hydro Atlas Jackplate - (2) 10 Foot Power Poles - Minn Kota Ultrex - Custom Rims
buzzers would be goin off bigtime if your hittin 7200 or it would blow, you definately have a tach problem and probably the wrong prop. WHat prop you runnin?
Tach Problem for sure, maybe something else to as far as speed. No way would the rev limiter let you turn 7000. I think the limiter on that motor is about 6200 and then she shuts down.
2018 Skeeter ZX 250
2018 Yamaha SHO 250
Minn Kota 112 Ultrex Link
Lowrance Elite Ti 12 and Elite Ti 9
Dual PP Pro Series II
Atlas Hydraulic JP
Sounds like a tach problem if your running 7k+ and still have pedal left. 55mph on that rig with pedal left sounds about right, at stock setup its only going to run between 58-60 WOT. Get the tach checked out.
Is the rev limiter set at the factory when the motor is being built or at the dealership. I guess the dude at the dealership was right but didn't offer to help while the boat was under warrenty and I didn't know either. The prop is a 23M. hole shot is very good it is just to many rpm's and not enough speed at WOT.
Modified by Skeet05 at 4:11 PM 3/8/2010
2018 Skeeter ZX 250
2018 Yamaha SHO 250
Minn Kota 112 Ultrex Link
Lowrance Elite Ti 12 and Elite Ti 9
Dual PP Pro Series II
Atlas Hydraulic JP
I have never heard any bells , whistles or anything. The more throttle you give, the more it revs.
You need your tach adjusted, your probably really hitting about 5500 and its reading 7000, the prop and slip numbers dont add up on the calculator
Is that a do-it-yourself or dealership job? I'm not to happy with my dealer. What is slip numbers, I'm not familiar with that term?
Skeet05, i had the same problem when i bought my boat brand new off the lot. After the breakin period, i was starting to open it up some and my tach was showing close to 7K R's. At the time i didn't have a GPS so couldn't tell you the speed. Basically my tach was off. Like others have said, it would have blown up by now running it that much. There are adjustment knobs behind the gauge but don't mess with them. My dealer connected some kind of meter to the back of the gauge and was able to set it up correctly. I would say let a mechanic adjust it before you start looking at other things. Any dealer or boat mechanic should be able to adjust it for you.
Your situation sounds just like mine when i got the boat.
YOU are not entitled to what I have earned!!!!!
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