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Is it OK to lower floats in a blower motor?

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Old 07-22-2002, 11:21 PM
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Question Is it OK to lower floats in a blower motor?

30' Sonic with Procharged 502s @ 6.5 lbs of boost and 15 lbs. of fuel pressure.

In rough water the carbs flood and both motors will hesitate for a second or two and then clear out. I am assuming it is flooding because there is black smoke when this happens, but not alot. Will 15 lbs. of fuel pressure keep the bowls full if I drop the floats down a little? I have them set now so that if I rock the boat a little gas will spill out. I have not checked them in the water, only on the trailer in a more level position.

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Old 07-22-2002, 11:46 PM
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I would try droping the fuel pressure -- 15 lbs is too much pressure for the carb. You are probably force feeding the carbs. Lower the fuel pressure to about 8 lbs with a regulator mounted as close to the carbs as practicle and get high flow needle and seat for the carb.
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Old 07-23-2002, 12:00 AM
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They regulator is set at 8 lbs. @ idle and climbs to 15 lbs @ WOT.
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Old 07-23-2002, 12:07 AM
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You should never have 15 psi at the carbs. That is way to much fuel pressure. 6-7 PSI maximum just make sure that your pump can keep up with the demand in gph. I also think that if your dumping this much fuel into the motor you might be washing down the cylinder walls thus shortening the life of the motor. Does your oil get dark fast?

Get that pressure down now!!!
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Old 07-23-2002, 12:08 AM
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It should stay at 8 lbs at any rpm. Get that pressure down. You are forcing fuel past the seats and overfilling the bowls. As the fuel pressure goes up the float level screw has to be set lower to compensate for the higher fuel pressure pushing down on the needle. The fuel pressure HAS to stay at no more than 8 lbs.
Replace the regulator with a good one -- racing style.
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Old 07-23-2002, 12:08 AM
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might try dropping pressure to 6# static (plus a 1 for 1 when indexed with boost).

should set float levels in the water at rest. just shy of the holes with the sight plugs out. (if you end up moving the level very much then you may need to verify your mainjet sizes afterwards).
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Old 07-23-2002, 12:24 AM
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Is this a blow through set up?? Carbs are in a box?? If so I stand corrected -- Then you have to get a regulator that is boost referenced. It has a line that goes to the box the carbs are in -or if it is mounted in the box you will still set it at 8 lbs and it will maintain 8 psi on the carb no matter what your boost is since it is in the boost along with the carb. Your fuel pump will have to put out at least 15 lbs pressure though.
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Old 07-23-2002, 08:25 AM
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Assuming the regulator is boost referenced the pressure the carb inlet needle sees is the gauge pressure less the boost. For example, with 10 lbs on the gauge and 4 lbs of boost, the net pressure at the needle is only 6 lbs. I found that dumping the floats when coming off a wave is a problem at anything over 5 lbs. I never run more than that, even with 1000 HP. I will add that any testing or dynoing is done at the 5 lb setting. I use a dual inlet float bowl if I am are worried about adequate fuel supply. You can spot this on the dyno if the engine gets leaner as the RPM comes up.
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Old 07-23-2002, 08:29 AM
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sounds like you have some big pumps with small regulators, I like the regulators that have a return line that helps a lot, also if you have holley carbs they make a tube that goes in the fuel bowl to keep fuel from sloshing around{slosh tube} they work, I have used them on other projects, good luck, and 15psi sounds a little high for myself there
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Old 07-23-2002, 08:44 AM
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Ken

First I would make sure fuel pressure is 6-7 when at idle with the top of the box off the carb. REREAD THIS -- ADJUST FUEL PRESSURE AT IDLE WITH TOP OF BOX OFF CARB. It may be correct now. (Your procharger may be putting positive pressure to the carb at idle & if you adjust fuel pressure with top on you may set pressure too low, mine has 2 psi at 1000rpm in box) Then I would adjust floats while boat is in the water. I had adujusted mine on trailer & when I got in water boat angle was different & had adjustment 2 high) Set idle speed if needed, then reinstall carb box top, don't forget to reconnect hose, & go BOATING!

If you are showing 15 lbs of fuel pressure with 6.5 lbs of boost in intake (maybe 8.5 in box) than the floats are only seeing maybe 7.5 now (not really that high). Some of the people that are responding to this thread are not snaping to that you are procharged & using a blow thru system.

Remember if you lean the motor out you will have bigger
problems that washed out cyln.

If you want to discuss further PM or email me with your phone # & I will give you a call.

Last edited by Turbojack; 07-23-2002 at 08:52 AM.
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