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Engine and Props

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Richard Perez

New member
I have a 262 Chris Craft cruiser. It came with a 350 Volvo Penta engine. Last summer I blew the engine and had it repowered. I replaced it with a Volvo Penta 454. I have duel props. Now that I have a more powerful engine should I consider changing the props for a different angle props . would it give the boat more torque an more speed ? an does anyone know he max RPM I should be running ?

Thanks for your Input.
 
The previous 5.7L engine required the 1.95:1 ratio Duo Prop.
Your 7.4L engine requires the 1.78:1 ratio Duo Prop.
This is important that it be correct.

As for prop series selection........, you'll do the WOT RPM test just as you would if single prop drive.


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RicardoMarine said:
The previous 5.7L engine required the 1.95:1 ratio Duo Prop.
Your 7.4L engine requires the 1.78:1 ratio Duo Prop.
This is important that it be correct.

As for prop series selection........, you'll do the WOT RPM test just as you would if single prop drive.


.
Click to expand...
i.e.,.... look up published max RPM range for your engine. With "normal" load, the engine should, at wide open throttle (WOT), run somewhere in that range. If it doesn't, you need a prop change. For maximum engine life, once you are propped to run @ WOT within that rev range, you should limit you cruising RPMs to 80 % ( 75 would be better) of the actual max RPMs that you get. I only run my engine up to WOT 2 or 3 times a season. Once soon after launch in the spring to make sure all is well, once mid season, and sometimes on the way to haulout. I NEVER run longer than it takes to verify RPMS and check water temp ( make sure its not rising, usually just 15 t0 30 seconds) and a fast peek at the oil pressure. Of course
if I found myself in a potentially dangerous situation, where WOT would be the order of the day... then, as needed. In 50 years of boating I only had to do this ONCE!
 
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