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Old 10-15-2018, 05:30 PM   #1
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Performance numbers

Hoping some fellow members running a 30' Pilot II 2003 or newer with the 315 Yanmar can post some performance numbers. Looking for RPM on the top end with knots or mph. Thanks in advance.

regards Holty
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Old 10-17-2018, 09:37 AM   #2
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Holty,
I have a 2006 rag top, 315hp. I run 3000-3200 at 16.5 -17.5 knots. I hit 20-20.5 knots wide open, 3800 rpms.
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Old 10-17-2018, 07:31 PM   #3
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Thanks jskinner. I have very similar speed numbers but my top end rpm only shows 3450. It is my understanding the 315 should turn 3900 to 4000 on the top end. Now wondering if my tach is off. I had planned to pull the wheel this off season thinking I was over propped. I am going to have my mechanic use his hand held strobe tach to check it out.

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Old 10-17-2018, 07:41 PM   #4
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Greetings,
Mr. h. @3450 what is your speed?
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Old 10-17-2018, 07:45 PM   #5
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Definitely check wot rpms with a photo tach before doing any thing else. In my limited experience, Mainship propped their boats pretty good, ie high rpms as opposed to others who overpropped them straight from the factory. Is it possible a PO changed the prop?


That much difference between expected wot rpms (3,800+) and actual if verified is cause for serious concern.


Also I am aware of one other Pilot 30 who trashed his turbo due to sea water backing up in the exhaust. If your exhaust turbo throat is corroded that will result in less power and lower wot rpms, but so will fouling on the bottom or prop.

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Old 10-17-2018, 08:17 PM   #6
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Greetings,
Mr. dj. ALL valid points. IF the tach is off, he should still be able to achieve close to the 20 knots Mr. jsk posted thereby confirming a low reading tach, given, as you mention, clean bottom and good turbo.
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Old 10-18-2018, 07:46 AM   #7
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Yes, I am hitting the same 20.5 knots at wide open throttle (3450 rpm). I will be checking the tach. thanks

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Old 10-18-2018, 10:07 AM   #8
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Not surprising as engine wot power curves usually are pretty flat for the upper few hundreds of rpms. But if the engine is putting out the same power at 3,450 vs 3,800 then the engine's internal stresses are 10% higher at the lower rpm and even more at rpms lower than that. That is why you want to rework your prop to get back to the engine manufacturer's designed stress levels.


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