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Calling the boat carb masters, lots of fuel still lean.

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Calling the boat carb masters, lots of fuel still lean.

Old 06-21-2021, 11:34 PM
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Default Calling the boat carb masters, lots of fuel still lean.

Hey guys first post but have read alot just always found my answer with out having to ask. This one has me stumped maybe just not being egressive enough. Start off (before the coast guard shows up its got j tues and a sealed base plate). Here is what I have is a 89 baja 210 sport 2005 vortech roller motor, healthy cam, behive springs, roller rockers, air gap dual plane, super sucker combo spacer, hardin risers, DUI HEI, MSD wires, 36 total advance. 420-425 hp Swings a 23 pitch mirage plus runs low to mid 70s.

Carb is a 650 hp center, billet fully adjustable blocks, emulsion circuit is stock .028 in all three. IFR s are .033, 7.5 pv (mid cruise vacuum is 9-10), .0047 pvcrs, front squirter 40 blue cam, rear 37 pink cam, 71 idle bleed, 31 high speed bleed, 75 primary jet, 82 secondary jet. Carter pump 6.5 psi idle WOT.
In my world that all means a bunch of fuel especially for a small chev but this is the first one I have had hopped up in a boat.
WOT it sounds good and runs like it. The rest of the time it sounds lean and the plugs show it. My question is how does my setup look for a boat carb first. Second I bring the power valve in sooner or make it worth less jet and run it richer on the primary main? Third plug the power valves and square jet it? Fourth plug power valve square jet it and put a 1:1 linkage just go all in on useing lots of premium......just say mid 70s with a small block isn't free lol.

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SB (06-22-2021)
Old 06-22-2021, 06:28 AM
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How does it sound lean ? A pop or two here and there thru the intake and carb ?
Do the plugs look unused , mistaken for lean ? This can be some water mist at idle from 'the big cam' that you never mentioned what it is and it's spec's. Let us know this.

Speaking of which, is this a 350 or 383 or ???? Compression ? Plugs ? Pics of used plugs ? Wideband readings ?

Also, hard for us to help with jetting specs , unless someone has used the same as you, because all carbs are different.

Without a wideband, I would add two jet #'s frt and back and see if performance picks up. If it does, try two more #'s higher. So on and so forth.

Case in point, a 9:1 350 I have worked on with Comp 218/224 at .050" HR with BrodixIK180's has a Barry Grant 650 VS card and uses 75/85 jets primary 6.5PV and is pretty well dialed in. Seems like a lot of jet for 350 with Holley type 650 carb, but it is what it is. Many other 600-650 Holley's or Holley types would be somewhere around 68/76 or so on that engine.
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Old 06-22-2021, 07:30 AM
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With out wideband o2 you are throwing darts at the wall . With a blow through set up you have to raise the fuel pressure when you increase the boost pressure with a boost referencing fuel regulator .
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Old 06-22-2021, 09:09 AM
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350 cubic inch, 9.8:1, I will dig up the cam card at lunch. When I say it sounds lean it sounds raspy at say cruising 2500 rpm. Then shut it off check the plugs and they are crispy white no color. They are not rounding the edges or have any signs of detonation. Goose the throttle and it cleans up for just a second when it gets the pump shot then back to lean. I will take a couple pics of the plugs tonight.

I thought about putting the wide band on it....just don't best way to go about it. Think it will get too much water with a block under the riser. Then there is put it right up next to one of the ports where there is no jacket or go through the jacket with a sleeve.
Really what to try and do it with out messing around putting the O2 sensor on it.


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Old 06-22-2021, 09:58 AM
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Originally Posted by green lightning View Post
With out wideband o2 you are throwing darts at the wall . With a blow through set up you have to raise the fuel pressure when you increase the boost pressure with a boost referencing fuel regulator .
Agree on the wideband.
On the blow through. I see he typed Vortech. I think he meant Vortec.
OP, you don't have a Vortech supercharger on it do you?
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Old 06-22-2021, 10:07 AM
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probably Vortec heads
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Old 06-22-2021, 10:35 AM
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I would think that is what he has he must have misspelled Vortec .
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Old 06-22-2021, 12:13 PM
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Sorry did spell vortec wrong it is a NA vortec hydraulic roller cam motor.
I think it telling me it just needs some more fuel from the transition circuit. Then make the PV worth less right now flow area is right on 7 jet sizes. Maybe it needs to be like 4 jet sizes then bring in the power valve sooner say 8.5 9.5 or so. Basically making it all richer and more sensitive. But the constant load boat thing maybe messing me up. How close to cruise vacuum should the PV be? Problem i just can't get past that i know if I took the thing off the boat and put it on big block truck rich as it is now it wouldn't even run but its truck not a boat.

Guess I am trying to get it closer faster with some knowledge from you guys that might have setup a boat carb from scratch like this.

Thanks for your help guys
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Old 06-22-2021, 01:51 PM
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O2 sensors are easy to install, I made the spacers for mine, and with an extension like the Innovate motorsports one, they should stay dry.


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Old 06-22-2021, 04:45 PM
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What size are the boosters and angle channels? I am thinking they should be around .140. If they are too small you can throw more jet at it and it won't help.
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