SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: eliminator18 on March 15, 2014, 03:32:54 PM

Title: Carb jetting help?
Post by: eliminator18 on March 15, 2014, 03:32:54 PM

I have a stock 454 with edelbrock intake, It had a holley 600cfm carb on it, I swapped it out with a brand new holley 750dp, when I had it at the river, it starts fine and runs good if you don't mash on it, the current jets are 72/80 with a 65 power valve, can someone help with the jetting size


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Title: Re: Carb jetting help?
Post by: beerjet on March 15, 2014, 03:41:48 PM

IMO.....your jetting is too far apart.
And what size squirter is in it?
Make sure the accelerator pump are adjusted properly too.

-beerjet-

Title: Re: Carb jetting help?
Post by: eliminator18 on March 15, 2014, 04:11:02 PM

Squirter says 28 and the other I think says 31


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Title: Re: Carb jetting help?
Post by: eliminator18 on March 15, 2014, 04:12:34 PM

Can anyone recommend a better jetting size


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Title: Re: Carb jetting help?
Post by: crewchief22 on March 15, 2014, 10:43:36 PM

Quote from: eliminator18 on March 15, 2014, 03:32:54 PM

I have a stock 454 with edelbrock intake, It had a holley 600cfm carb on it, I swapped it out with a brand new holley 750dp, when I had it at the river, it starts fine and runs good if you don't mash on it, the current jets are 72/80 with a 65 power valve, can someone help with the jetting size


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What is it doing when you get in the throttle hard?

Holley used either 70 or 71 primary jets and 80's secondary.   The first thing I'd do is change the 6.5 power valve to a 3.5.  That'll slow down how quickly it starts dumping fuel through the power valve.

Inspect your plugs or install a fresh set then get a plug reading after a full throttle pass.  That'll help you determine if you need to adjust jetting or start looking for another issue.
 

Title: Re: Carb jetting help?
Post by: eliminator18 on March 16, 2014, 02:08:24 AM

When I get on it, the engine stumbles and just about dies out, I have to ease into the throttle for it to run. It revs fine when it's out of the water, but in the the water under load it is a different story. I'm going to check the vacuum reading to see if the power valve is the right one


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Title: Re: Carb jetting help?
Post by: beerjet on March 16, 2014, 02:38:07 AM

Accelerator pump maybe....
Why not just square the carb up and plug the power valve?

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