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Old 08-27-2019 | 02:29 PM
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GPM
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Some people drill small holes in the throttle blades so you're not adjusting the idle screw out of the idle circuit.
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Old 08-27-2019 | 02:46 PM
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That's what I'm kinda thinking..Just watched a video on you tube about it actually....my question to that is...in that video he says an indicator that you are outside of the idle circuit is the low speed enchrichment adjustments won't do anything when adjusted...well mine do a ton when adjusted so does that mean I'm good and should look elsewhere or is it something could still be an issue?
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Old 08-27-2019 | 03:01 PM
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Boost referencing would give you a true vacuum signal versus what you'd get directly under the throttle blades. It would help the tuning process. There's a lot posted in the forum about the process.

I never got to it with mine, but had planned to. I ended up selling the boat before the next season got underway. Locking the timing at 30 degrees helped some too. Still, it would roll a good 500-600 RPM at times. People thought it sounded bad ass, but for me it was a big pain. Mine was a much smaller 250 with 850 Nickersons (dual).
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Old 08-27-2019 | 04:10 PM
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Do your carbs have 4 corner idle adjustment ? how far are the blades open now ?

Last edited by GPM; 08-27-2019 at 04:12 PM.
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Old 08-27-2019 | 04:13 PM
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Yes 4 corner on both carbs and the slightest adjustment of any of the 8 screws can either be heard and seen in the engine or at a minimum observed on the A/F gauge

Wasn't aware that boost referencing had such a big impact all the way around...thanks for the info!!
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Old 08-27-2019 | 04:16 PM
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Are you seeing major changes to the A/F ratio when it surges ?
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Old 08-27-2019 | 06:11 PM
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Id like to know how having a boost referenced carb which opens a power valve after it sees boost has anything to do idle
??
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Old 08-27-2019 | 09:38 PM
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It was explained to me that the power valves would be more in line with the actual needs of the engine. That’s all from reading and seeing others have good results vs my own practical application. I do know that the boost referenced carbs on the engines in my buddy’s Bullet have worked very well... a little bit of roll but nothing like what I had with mine.
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Old 08-27-2019 | 09:46 PM
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I disagree with all of that . I have 3 years of playing with power valves , boost referenced carbs , and checking EGT and AFRs` . The fuel curve got a lot better when I threw the power valves in the garbage and plugged the boost reference crap.
Does your buddy monitor AFRs thru out the entire RPM range? Running great , not sure what that means. Youd never know mine was pig rich after the power valve opened and dumped a bunch of unmetered fuel . I even played with the power valve restrictors, what a waste of time
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Old 08-27-2019 | 10:30 PM
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I hear what you’re saying. With the Bullet it’s very old school. The work was done a long time ago with a couple of refreshes in the mix. It’s been run without changes for over ten years. I will say that they’re being changed to a different set up and will be run on the dyno to get them right.

I’m not an expert here... just passing on what many have mentioned about the carbs working better all around when boost referenced.
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