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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 07-07-2021, 12:21 AM
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Now on to the next question suggestions on high flow fuel separator just to get it out of the way? Going to see what's going on with the pickup see if that is hindering it.
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Old 07-07-2021, 11:54 PM
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I guess I lost everyone after the leveling for the telling my carb is junk and belongs on a mustang. Maybe I know a little bit more then I was letting out about carbs and hot rods in general. Sorry if I offended anyone.

Back to ringing every last hp, ftlb, and mph out of a vortec 350....why....because I can. If it burns a piston, valve, kicks a rod or what ever it was the poor unsuspecting small blocks time.....what happens then we build better one. It is almost ill handling like it is anyway was wanting to chine walk right off the trailer till I realized it was having fueling issues and had to be nicer to it till I could do some more diagnosing. So come back with me.

So after a couple maybe questionable changes to the carb setup (depends on who you ask....just saying). It still boils down to fuel supply. Floats up, floats at stock made about a 2 second change in having lean issue. So tonight I did what I should have done from the start. Take the rest of the fuel system off and lay it on the bench and check it out. Found 3/8s pickup perfect except for the cheesy screen stuffed in the end of it 👎 (never seen that in any of my other boats). Next (I know it was mentioned just ran out of time to mess with it) fuel seperator off and apart (I know should have looked at it for what I am doing) one look it hit trash can where it belongs.

I didn't get any replys on fuel seperator going to go 33405 wix seperator (readily available if it gets pluged) Give all the sharp edges inside the mount a tune up. 8an off the tank to seperator to 175gph 100 micron strainer, 100 gph (about 50gph at pressure) pump 6an to 100gph 40 micron filter 6an to carb, regulator, then back to tank. Should cover it and cover it if I dig up a blower for it....weather I should or not.

Constructive thoughts?









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Old 07-08-2021, 12:21 AM
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Waste of time to run 8 AN from the tank to sep filter. 3/8 will support 550 hp
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Old 07-08-2021, 10:42 PM
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Originally Posted by Griff View Post
Waste of time to run 8 AN from the tank to sep filter. 3/8 will support 550 hp
Reason for the 8an feeding the pump is that it needs larger feed line then it does on the outlet because your compressing the fuel. The bigger pump you have the bigger feed line you need if you want it to live a long and happy life. Few 90 degree fittings 180s and a to small of feed couple other restrictions and 550 hp potential quickly becomes 350 hp potential. Other side is if you have a monster pump with a good sized feed it will make enough volume and pressure to make it through all the restrictions and still have enough volume left to make 7psi and still flow 50-100 gph and support the horse power. If that makes sense.
My boat is a fine example of all of this. I started with a 70 gph free flow pump making 6.5 psi at about 40 gph. Holley with with 110 needles needs 4.5-5 psi WOT to keep the jets fed. I'm good for 475 to 500 hp.... 400-450hp being conservative with some left on a dead head system. Same system put bigger pump on 100 gph free flow right around 55 gph at 7psi capable of up to 15psi with a return regulator after the carb so the needels can see full potential of the pump say 40 gph at 4.5-5 psi still good for 450 hp at a bare minimum. Bigger pump sucking on same straw same problem. All adds up the not enough feed to the pump if that makes sense. Probably get away with 6AN now that I got other restrictions out of the way. 8AN is just extra insurance, if I wanted to take the tank out and weld in a bung it would have a 10an feed line.

thanks for the input





Last edited by Tfmech; 07-08-2021 at 11:20 PM.
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