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I swapped an old pump out with a newer , fresher one . The old one was a very old style JC that sounded like it had a bent shaft and it now has a newer JG and I assumed the old pump had an A imp. The fresh one has an aluminum A . I put it in a 21' hallett with a very stock 454 . The motor now revs up past 5k (according to the 35y/o tach) with no problem which it didnt before. It feels like it lost some MPH though . I'm gonna mess with some wedges to see if it frees up a bit.
The only conclusion I can come to is that the old impellor was an AA. What do you guys think would cause these results .
-beerjet-
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That's what I would think if your RPMs went up.
Try swapping the impeller with the one in your old jet.
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That's what I would think if your RPMs went up.
Try swapping the impeller with the one in your old jet.
I would really hate to take a fresh pump apart since that would involve some down time .
-beerjet-
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Or since you know that your new one has an A, take your old one apart and see if it is in fact an AA. It should be stamped on the impeller somewhere.
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Or since you know that your new one has an A, take your old one apart and see if it is in fact an AA. It should be stamped on the impeller somewhere.
There in lyes the problem . It doesn't say anything. I tryed to measure it but the phockin shaft is in the way to get an accurate measurement.
-beerjet-
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I tryed to measure it but the phockin shaft is in the way to get an accurate measurement.
-beerjet-
Uh...that sounds like a personal problem dude. :crossx:
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What impeller should I be running in my 77 Tahiti ski boat? The 455 never lacks for power or seems like its overloaded, is there a more agressive impeller I could be running? I dont know what is in it now, is it possible to see through the inspection hole?
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Check the tach, would be the first step. The fact you upgaded pumps means nothing, the newly installed pump could be loose, out of tollerance, and the impeller could be worn. You need a few more pieces to the puzzle to get your answer, and yes the impeller could be an A, but it's not likely you pull more then 5k on a stock motor. good luck
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As stated above, you're pissing in the wind on this one. You need to measure the old impeller (I don't see how the shaft would be in the way of a set of calipers), measure the new impeller in the new pump, the verify the clearances in the new pump. The pump being "fresh" shouldn't mean that it will cost you anyting to check these things. Pull the bowl and check the clearances.
Assuming your tach is resonably accurate, I'd bet that the "A" that is supposedly in the fresh pump is either loose or undersized. A stock 330hp 454 won't pull 5k on a tight "A" impeller that is loading well.
Chris
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my "new" pump came out of my other boat which does have more HP and worked perfectly and only has a season on it with little use . I really dont care how much RPM it pulled . I'm more concerned with the fact that is slower. It's not a hot rod anyways but I lost MPH and that's my concern.
-beerjet-