Yamaha 225 on a key west 23 ft boat

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Mbrya44206

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Feb 1, 2011
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I purchased a 2010 key west 225 dual console with a yamaha 225 four stroke and I feel it does not work effectively on the boat. The fact is with the original stainless prop it took a long time to plane out. The marina then put a smaller prop on the engine and it planes out quick but then revs at high rpm at low speeds. Did I need to buy the yamaha 250 engine. The marina is suggesting an aluminum 4 blade.
 
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yamatech43

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Feb 9, 2011
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Re: Yamaha 225 on a key west 23 ft boat

Motor isn't the problem....it would be of great help to yourself to if you troubled to learn a little about props...basics are...go to a prop shop or dealer...stay away from marina....borrow(yes they will have a prop for you to borrow...will be just basic old prop but will do what you need) that they think will be about right....i'd guess 19"x14" or so...the first number is the pitch...for this motor will be choice of 19 for power or 21 for top speed(on a lighter load)....your boat isn't that light so will be 19 pitch....the second is the diameter if you spun the blades the outer arc would measure this....try a "average prop like 19x14 and get your top speed and rpm....this is the trick....the engine must turn within 200 rpm of top rpm at top speed....whatever that speed is....if you are turning 5900 rpm at 40 mph then 40 mph is top speed of this package(boat/motor)...if you top out at rev limiter then you may try a SLIGHTLY larger prop....one inch of pitch equals 200 rpm...props are normally sold in 2" pitch increments so you will be changing by 400 rpm if go to 17 or 21 from 19....17 will be more rpm...21 less....can insead change diameter in smaller bites....hope this helps.
 
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99yam40

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Re: Yamaha 225 on a key west 23 ft boat

That's strange, I have never seen a prop listed with the pitch first, all I have seen are diameter first and then the pitch
 
SparkieBoat

SparkieBoat

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Re: Yamaha 225 on a key west 23 ft boat

I am not sure but I think those motors are recommended to be at 5500-5800 RPMs at WOT..that has been my rule of thumb for almost every motor I have ever set up..I usually shoot for 5800 unloaded. I have heard that 6K on those 4 strokes is not good..I think 6200 kicks in the rev limiter. but I am not %100 sure for the 225...25 HP will always help some..that would be about a %10 increase..but since you have already purchased that set up you are kinda stuck with it unless you are willing to shuck out some more money and take a loss on the 225. this is why you always test drive a boat BEFORE you purchase it, if it is not fast enough for you, get a faster setup...but if you really want some speed..go ahead and get the 300 if your boat is rated that high..then it will jump up and run out nicely.
 
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cranebug

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Re: Yamaha 225 on a key west 23 ft boat

I came across this and did not have a chance to look at the performance bulletin. I have an 04 225 Bluewater with a yamaha F225 which was overpropped (aluminum) when I bought it. After way too much analyzing, I was able to find a prop to "match" the performance bulletin recommendations and it works wonders. (search for your KW performance bulletin; great starting point) In my case a Yamaha Salt water series II 15 1/4 x 19 was recommended and works to the performance spec. (approx 49MPH @ 6,000). I would further suspect that if your model is similar to mine, you will need to trim your tabs down, trim the motor down, and get right onto the throttle to get up quick (otherwise the bow will be straight up and you won't be able to see!) Once you are up you can throttle back to a safe speed while still on plane, and then trim up as warranted. It will also help to have some of your gear and weight forward. I will be happy to discuss further as I HAVE Been through this.
 
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user64

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Apr 5, 2009
Messages
54
Re: Yamaha 225 on a key west 23 ft boat

It would be helpful if you could provide your performance numbers with your current prop. Sounds like prop but could be other causes like engine mounted too low or even engine problem itself. You will need those numbers to determine what pitch prop to go to as well. I would think that the 225 should move a 23' boat along pretty well.
 
SparkieBoat

SparkieBoat

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Re: Yamaha 225 on a key west 23 ft boat

I have a 20' well craft with a 200 HP motor..unloaded I can barely break 44 MPH..I would think you should be looking at around the high 30s..maybe 38-39
 
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cranebug

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Re: Yamaha 225 on a key west 23 ft boat

No disrespect meant Sparkie; but your circumstances and the OP's are not the same. I have a 2004 Key West 225 with a Yami 225. When I finally got the correct prop I am drawing "close" to performance bulletin specs of close to 50 MPH at 6,000 rpm (gps). I am very happy with the performance. My point a few posts ago is that the performance bulletin should be a close starting point for Prop spec. (btw) we have not yet heard back from the OP?
 
SparkieBoat

SparkieBoat

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Re: Yamaha 225 on a key west 23 ft boat

I just posted what I am getting with my boat. no disrespect taken. My 20' boat is older and is a deep vee. not sure if that makes a difference. But I do think that the max recommended RPM for that motor is 5800. And I still stand by my statement that you should do a sea trial before you buy a boat, most dealers will be happy to accomidate a serious buyer with one. If boat does not preform as you hope, then get another boat/motor.
 
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cranebug

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Re: Yamaha 225 on a key west 23 ft boat

Ok Sparkie, What I was getting at is that your speculation of the high 30's is far short. I have researched this to the ends of the earth to get my boat where it should be; and against the opinion of a ton of folks, I was able to obtain a prop (based on the performance bulletin) for my boat and I am happier that a pig. Room for improvement? possibly. But close to 50 mph at 59 to 6,000? how and when can you go faster. I have an 04 225 yami and that is the recommended rpms. The regulator/limiter will/should kick out at approx 6200. However, I know what the OP is talking about.. the boat is "tough" to get up if you baby it. Like my original post said, trim down, tab down, and get right onto it! Then throttle back when you are on plane (which is very quick). So what I am saying is the F225 is plenty of power for that boat. It is imperative that it is propped correctly, and as someone else mentioned the height of the motor is also important. Bottom line: check the performance bulletin which will tell you the test prop, motor height, and test conditions. Easy place to start.
 
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cranebug

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Re: Yamaha 225 on a key west 23 ft boat

Sorry forgot: I hear you on the sea trial etc. I had to figure out the nuances of my boat but I have to tell you; other than being covered in a snow bank right now, I LOVE IT!
 
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