SoCal Jet Boats

Tech Talk => Jet Pumps => Topic started by: jamiemwedmore1234 on June 26, 2014, 12:05:40 PM

Title: Rpm question
Post by: jamiemwedmore1234 on June 26, 2014, 12:05:40 PM
This is for a buddy's boat. Has a brand new A impeller new main bearing new shaft and a fresh 400 hp bbc  boat only spins 3400 rpm thought a. A impeller was pretty standard it's a jc pump ans a 18 ' boat


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Title: Re: Rpm question
Post by: jamiemwedmore1234 on June 26, 2014, 12:11:55 PM
3400 rpm seems a little low boat gps at 62 mph  @ 3400rpm


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Title: Re: Rpm question
Post by: GT Jets on June 26, 2014, 12:13:06 PM
This is for a buddy's boat. Has a brand new A impeller new main bearing new shaft and a fresh 400 hp bbc  boat only spins 3400 rpm thought a. A impeller was pretty standard it's a jc pump ans a 18 ' boat


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Not enough information, but doubting the 400HP thing.

Something is wayyyy off.

I have a small block Chevy that will turn that pump to 4200.

GT

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Title: Re: Rpm question
Post by: jamiemwedmore1234 on June 26, 2014, 12:17:17 PM
I told him the same thing but from what I no it's a 468 with a 750 carb 34* timing open header large oval port heads  I told him to hook up a diff rpm gauge


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Title: Re: Rpm question
Post by: SNiC on July 01, 2014, 02:19:08 PM
3400 rpm seems a little low boat gps at 62 mph  @ 3400rpm


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62 sounds about right but the 3400 RPM????..... I would verify the tach is correct......
Title: Re: Rpm question
Post by: jamiemwedmore1234 on July 02, 2014, 12:30:08 AM
Yes it was the tac rev it on the trailer and would only rev to 3500


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Title: Re: Rpm question
Post by: eliminator18 on July 02, 2014, 03:02:58 PM
I had the same problem, found it to be the stock ignition module, replaced it with a flame thrower module and that did the trick!


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Title: Re: Rpm question
Post by: 396bbc on July 02, 2014, 06:32:36 PM
Mine wont turn over 4500 on my 396

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