Boat won't Rev passed 3800

« **on:** April 13, 2016, 05:30:40 PM »

Bought eliminator day cruiser with blown motor, put rebuilt motor in and can't get more than 3800 rpm. Mild 454 dominator jet not sure what impeller or how to check! 850 double pumper! Hei ignition! Any info would be appreciated. Kinda stumped at this point

« **Reply #1 on:** April 13, 2016, 06:03:29 PM »

Have you checked to see if anything is stuck in the pump

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« **Reply #2 on:** April 13, 2016, 06:42:18 PM »

Quote from: placecraft jess on April 13, 2016, 06:03:29 PM

Have you checked to see if anything is stuck in the pump

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That'll do it. Lol

More information about the tune.

What cam?
What ignition?
WOT timing?
Run rich, lean?
Secondaries opening?
Tach correct?
What exhaust system?
Temperature?

I could go on forever, but you get the idea.

GT

« **Reply #3 on:** April 13, 2016, 06:58:32 PM »

Crane534 lift 226 duration Hei 8degrees 34 total seams lean just changed from edelbrock 750 to 850 holley has logs runs at 150 degrees and new hardin marine gauges with same results as s old. Kind of thinking pump but know 0 about them. Kind of scratching my head now

« **Reply #4 on:** April 13, 2016, 07:10:46 PM »

Quote from: 77 - eliminator on April 13, 2016, 06:58:32 PM

Crane534 lift 226 duration Hei 8degrees 34 total seams lean just changed from edelbrock 750 to 850 holley has logs runs at 150 degrees and new hardin marine gauges with same results as s old. Kind of thinking pump but know 0 about them. Kind of scratching my head now

Might be time to pull the pump apart.

Where are you located?

« **Reply #5 on:** April 13, 2016, 07:13:01 PM »

Kind of what I was thinking. I live in orange county damn money pit

« **Reply #6 on:** April 13, 2016, 07:30:00 PM »

First things I would do would be climb under the boat and look in the intake see if you see anything obvious then if you can take the inspection plate off and look in there you might just have a rope are something stuck

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« **Reply #7 on:** April 13, 2016, 10:19:41 PM »

I had a similar issue when I replaced my gauges... it sounded like my motor was running fine but the tach only read 3500rpm. turns out I just forgot to set the back of the tach to "8 cylinders".. damn thing had me stumped for a few trips.

« **Reply #8 on:** April 14, 2016, 07:17:51 AM »

Thanks for the reply pump is clear and gauge is set to 8 cylinder think I'm in for pump work guess you can't believe what people tell you when you purchase supposed to have been fresh with the new transom

« **Reply #9 on:** April 14, 2016, 07:40:00 AM »

Fuel filter... just an idea.

« **Reply #10 on:** April 14, 2016, 09:11:19 AM »

Quote from: 77 - eliminator on April 14, 2016, 07:17:51 AM

Thanks for the reply pump is clear and gauge is set to 8 cylinder think I'm in for pump work guess you can't believe what people tell you when you purchase supposed to have been fresh with the new transom

FYI, it would be very rare for a messed up pump to hold the engine back.

If there are no rocks in it, the problem is elsewhere.

JMO

GT

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« **Reply #11 on:** April 14, 2016, 09:14:07 AM »

Quote from: 77 - eliminator on April 13, 2016, 05:30:40 PM

454

Think I found the problem!

« **Reply #12 on:** April 14, 2016, 09:16:06 AM »

How about empeller size if wrong for my application not sure what it has and don't know how to tell

« **Reply #13 on:** April 14, 2016, 09:24:43 AM »

Quote from: 77 - eliminator on April 14, 2016, 09:16:06 AM

How about empeller size if wrong for my application not sure what it has and don't know how to tell

With a meager 300 horsepower you should be able to spin even an AA over 4k.

High Helix maybe not, but you don't have one.

Have any details on the pump build?

He should have been able to provide some insight.

What impeller as an example?

I had a 355 cubic in. mouse spin an AB at 4,200 rpm. Having a hard time believing a big block with 100 more inches couldn't to at least the same with even an A.

JMO

GT

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« **Reply #14 on:** April 14, 2016, 09:26:00 AM »

I'm thinking the carburetion is off or the fuel pump is falling behind.

What makes you say it's lean?

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« **Reply #15 on:** April 14, 2016, 09:28:29 AM »

Quote from: el mojado on April 14, 2016, 07:40:00 AM

Fuel filter... just an idea.

^^^ This, as well as fuel pressure, fuel volume, tanks vented (creating a vacuum), cracked fuel lines sucking air, the list goes on...

In my experience, something in the pump, or a loose pump = high rpm, not low rpm. 3800 rpm & AA= ~225 hp, and an A is ~200 hp, depending on your build, you are missing ~200 hp, or so or about 1000 rpm.

Definitely check the tach accuracy. 1-2% is livable, 10% is 380 rpm, witch is either 4180 (hi side) to 3420 (lo side), still dismal for a BBC.

Check all the things GT said, too

Dan'l

« **Reply #16 on:** April 14, 2016, 09:34:05 AM »

Quote from: GT Jets on April 14, 2016, 09:24:43 AM

I had a 355 cubic in. mouse spin an AB at 4,200 rpm.

GT

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Glenn-

Bone stock sbc?

My ZZ4-ish motor spins a AA (American Turbine) at 4200. swapping it out for an A (Berk)

Dan'l

« **Reply #17 on:** April 14, 2016, 09:46:47 AM »

Thanks on pump info know nothing about them at all first one I've owned. Sorry outboard convert like in earlier post switched from 750 edelbrock to 850 holley with better overall performance but still only 3900 rpm boat doesn't stumble at all just stops pulling will check fuel pressure next sure would be nice not to have to do a pump before the season

« **Reply #18 on:** April 14, 2016, 09:52:45 AM »

Quote from: mash on it on April 14, 2016, 09:34:05 AM

Glenn-

Bone stock sbc?

My ZZ4-ish motor spins a AA (American Turbine) at 4200. swapping it out for an A (Berk)

Dan'l

Very few GM parts.

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« **Reply #19 on:** April 14, 2016, 10:11:22 AM »

Quote from: GT Jets on April 14, 2016, 09:11:19 AM

FYI, it would be very rare for a messed up pump to hold the engine back.

If there are no rocks in it, the problem is elsewhere.

JMO

GT

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I agree I was thinking something was stuck in the pump. are you sure your getting full throttle. Did you spin the pump over by hand before hooking it up to the motor.

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« **Reply #20 on:** April 14, 2016, 10:25:43 AM »

Can't see anything in pump did spin fine and do have full throttle. Is a head scratcher for sure probably be something easy I'm overlooking that's why I'm consulting the pros

« **Reply #21 on:** April 14, 2016, 10:29:09 AM »

whats your timing set to?

Check fuel pressure

Check fuel filter

Verify theres nothing int he fuel lines or tanks/no cracked lines

try running it with a gas cap off see if that helps

« **Reply #22 on:** April 14, 2016, 10:36:28 AM »

Will try all these tips hopefully on Sunday at Elsinore

« **Reply #23 on:** April 14, 2016, 10:41:54 AM »

Quote from: FordLover on April 14, 2016, 09:14:07 AM

Think I found the problem!

Probabley right my powerstroke runs bitchin maybe I should put that in it almost spins as high and fuel is cheaper

« **Reply #24 on:** April 14, 2016, 05:30:47 PM »

So,you replaced motor,was it ok and running??

850 d/P carb,rebuilt and was it ok and running??

HEI ignition, checked and running??

3800 rpm.....is that in the water or on the trailer without any load.

Otherwords,you've tried your boat/pump on the trailer with the garden hose hooked up?

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