Float adjustment

roblenderman · #1 (**permalink**) 04-08-2004, 05:51 PM

I have a Street avenger 770 on a 351W stroked to 392. The engine is new from Roush. I checked my float levels after having a hard time once the weather turned warm and they were so high fuel was coming up the air horn. I turned the adjusting nut clockwise to lower the float and fuel level. I started the engine and let it idle for five minutes before stopping and rechecking the level by removing the brass screw in the sight window. After a few turns the level was just below the threads and a slight rock of the car would cause some fuel to escape. After driving a few miles and everything running fine I gave it hard gas. It made a small backfire and ran horribly like it was running really rich. The same way it was running before any adjustments. I took it home and opended the sight window to have fuel pour out again. I tried to lower the float some more but it is all the way down. The adjusting nut will not turn the inner needle any further down. What could be the problem?

Excaliber · #2 (**permalink**) 04-08-2004, 05:59 PM

Fuel pressure to high.

Needle/seat damaged.

Floats "heavy".

Occasionally the floats will "break down" in compostition and become fuel ladden internally and as a result become "heavy". If this is the case the only soluition is to replace them. IF they are the old bras type should be easy to tell. With the compostion material type it's more difficult.

Edley Rondinone · #3 (**permalink**) 04-08-2004, 06:14 PM

On a Holley, The nut just holds the adjusting screw in place. Loosen the nut, turn the screw, rock the car until gas gomes out the little hole, then tighten the nut, and put the little screw back in, where the gas came out the side of the carb.

Randy Gallagher · #4 (**permalink**) 04-08-2004, 06:38 PM

On a Holley and Demon the nut adjusts the needle&seat,the screw locks all in place.With motor off remove screw,turn nut counter clockwise to remove needle&seat look for a piece of debri between needle&seat

RedBarchetta · #5 (**permalink**) 04-08-2004, 06:46 PM

What Randy said. It doesn't take much to hang-up a needle/seat and cause a small flood in the bowl. I also used to get the viton tipped needles...they were more durable.

Excaliber was dead on regarding the floats as well. Sounds like to me it's either one or the other.

roblenderman · #6 (**permalink**) 04-09-2004, 11:37 AM

Turns out we had two problems. The first was that the float was a little high so it was running rich with the weather change. The other is that it had a large rubber shaving from a hose in the needle valve. Since it would float it would run fine once I set the float level but if I juiced it the fuel flow would cause it to get stuck in the needle value. Sometimes it would clear and the problem would disappear which seemed to happen every time I let it sit for some time. Thanks for all the help.

Rob