Can't get max rpm's out of Volvo IO

[thunder]

I have a brand new Stingray 185LX with a 135HP Volvo IO. I was told that max rpm was between 4800 and 5200, but I can only manage about 4300 to 4400 at wide open. I'm running a 12.25 X 21 pitch prop. I'd like to keep the same prop. Is there any way to bump the hp up to get the prop to spin faster?

 

[Dunaruna]

Re: Can't get max rpm's out of Volvo IO

The short answer is......no.<br /><br />There are lots of things you can do to TRY and tweak a few more horses but it's not worth it - you won't notice 5 HP and to get any more will rip a hole in your bank balance bigger than the grande canyon.<br /><br />My advise is to perform an extensive tune, then prop accordingly. And polish the underside of the hull. Or remotor to something bigger.<br /><br /><br />Aldo

 

[Bondo]

Re: Can't get max rpm's out of Volvo IO

I was told that max rpm was between 4800 and 5200,

Who told you That,..???.....<br /><br />You have a Brand New boat,... Doing Anything to the engine will Void the warranty,....<br />That little 4 banger Doesn't have anymore to Give,.....<br />If you want a Faster Boat,.... You Should have bought 1 with a Bigger Motor.......... <br />

I'd like to keep the same prop. Is there any way to bump the hp up to get the prop to spin faster?

Ayuh,......... Wouldn't We All,...............<br /><br />The Long Answer is the Same as the Short Answer,................<br />No,..... It Ain't Going to Happen..........<br /><br />Go Enjoy your New Boat,.................<br />Get some seat time,+ you can Trade Up in a few years,..........<br />After You decide Exactly What Boat you Really Want..............

 

[QC]

Re: Can't get max rpm's out of Volvo IO

Dunaruna and Bondo are all over this, but here is some info based on what you have now, which I agree with them . . . you're kinda stuck with .<br /><br />It looks like Volvo is recommending a MAX of 4600 RPM with your power package. So your prop is pretty close depending on how it is loaded and trimmed. If this is the best you can do with the boat lightly loaded and efficiently trimmed, then you can probably improve it with a prop change.<br /><br /> http://www.volvo.com/volvopenta/global/en-gb/marineengines/powerforleisureboats/gasoline_sterndrive/ <br /><br />Funny it doesn't give a range, but all of the other Volvo products have a 200 RPM swing which would say 4400 - 4600 in your case, but that is purely speculation on my part, your operations manual should confirm this. It sounds to me (if your tach is correct) that you can go with a 19 inch pitch prop and get possibly a little better performance.<br /><br />You should read the propeller selection and WOT threads in the Engine FAQ section. This could help you. Good luck!!