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Top speed 20 SLX 70 HP yamaha?

Pcoyne

Pcoyne

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Was wondering what my top speed should be? I was told 21-22 by dealer i am at 17 max at 4000 RPM.
 
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My 20SLM is right at 22-23 using GPS. 70 Yamaha at about 5000 rpm plus.That's with the Bimini down.
 
Pcoyne said:
Was wondering what my top speed should be? I was told 21-22 by dealer i am at 17 max at 4000 RPM.
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Somethings wrong. Too much prop?
 
Thing I'm wondering is, did it ever rev higher or has it always been like that? Do you trailer your boat or keep it in the water? A good buildup of algae will knock off 5 mph easy. If the toons are clean I would verify the engine is running properly, a clogged fuel filter or ignition problems would limit rpm's and power. If all that checks out then it's the prop.
 
I can do about 23 mph at 5700 rpms. That's with Bimini down and by myself.

At 4000 rpms I am doing about 15 mph. I would have the engine checked.
 
What size Prop, I have the same pontoon with a SS prop 11 pitch and I turn about 6100 RPMs and 19 to 20 mph with my wife and I and our Labrador retreiver plus a full tank.

I can get up to 23 mph with a 12 pitch ss prop at 5600 rpms.
 
Thinking I should bring back to dealer, they made the comment "I am sure we told you it will do 55 on the trailer" I really hate marinas.
 
Pat, 4000 rpms is too low I would think. You need to look at your prop and post what it currently is. Some of the prop guys will offer you suggestions and I think if you reprop you will be happy
 
I recently purchased a 20 slx with 25" toons with t50 Yamaha. By myself with full tank I run 20. With two three adults and few children I run 18 to 18.5, pulling tube with three kids on it I run between 16 to 17 mph. Sunday I had biggest crew four adults and four teenagers two kids all over 10 I ran 16.5 (GPS) with four on tube I ran 16.9 to 17.3 and with just two on tube I ran 16.5 to 16.9 kinda slow to get on top but when on top (tube) boat really took off. I think it was drag from tube because it was loaded LOL.
 
CrazyCajun said:
I recently purchased a 20 slx with 25" toons with t50 Yamaha. By myself with full tank I run 20. With two three adults and few children I run 18 to 18.5, pulling tube with three kids on it I run between 16 to 17 mph. Sunday I had biggest crew four adults and four teenagers two kids all over 10 I ran 16.5 (GPS) with four on tube I ran 16.9 to 17.3 and with just two on tube I ran 16.5 to 16.9 kinda slow to get on top but when on top (tube) boat really took off. I think it was drag from tube because it was loaded LOL.
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What prop do you have on the 50? 
 
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