Prop question

[Esquire]

I have a 360 convertible, 8.2 Crusaders rated at 4400 rpms at WOT. Ran her this weekend with three people, half water and full fuel tanks at WOT and recorded 4500 rpms on the port engine and almost 4600 rpms on the stb engine. I think I understand the problems if you are unable to get to your rated rpms at wide open throttle, what about if you are over them? and is this amount of being over an issue? Any input would be appreciated, I am "prop challenged"...:dunno:

[HisDoghouse]

For a diesel, being able to get up and over the max rated RPMs is a good thing. Good if when you're doing it you are not fully loaded and your bottom and running gear are clean. That way you can be reasonably assured that you will reach the rated RPM when your conditions are not optimal.

Why is that important? So that you are not overloading your engines. Overloading has been described as one of the frequent causes for engines to fail (at least diesels).

Another thing you might want to check is to confirm your tachometer accuracy with a photo-tach (strobe) that is considerably more accurate than most gauges. If the tachs are in fact close to the actual RPMs, I would not be concerned that you are getting slightly over your rated RPMs. Just don't keep it up there too long. And the way fuel prices are going, I doubt you would anyway.

Joe

[Esquire]

Thanks for the info Joe. I think overloading a gas engine is probably just as bad, or worse than a diesel. So at least it is not a bad thing to slightly over rev. and as you said the fact the standard issue tachs may be off a little bit as well. Given the fuel prices it was great to type "full" before fuel... too bad it doesn't stay that way.

[Maximillion]

Hey Esquire,

Are those Crusaders the 502's? I was looking back in our records and the only 8.2 were Mercs.

[Maximillion]

Hey Esquire,

Are those Crusaders the 502's? I was looking back in our records and the only 8.2 were Mercs.

[Esquire]

Hello Maximillion,
Yep they are the 502's, according to the serial numbers they were manufactured in 1998, the numbers are sequencial which is unusual as they rolled off the line one behind the other, they have the Muti Port Fuel Injection as well. Crusader Blue thru and thru. My boat was listed as a 2000 when I bought it but the hull number is a 1999 build. If I gave you the number is it possible to look up the records of the build? That would be interesting, sure hope they don't indicate that Mercs were installed...:blink: