I bought a 1998 scarab that has 4 gas tanks,the boat was in storage for 3 years!the 2 small 25gallon tanks seem to have bad gas in them .I have drained them several times and refilled them,every time I switch over to these tanks my right 525sc backfires threw carb,otherwise it runs fine,HOW DO I GET RID OF THE GAS THAT I CANT SEEM TO PULL OUT OF VERY BOTTOM OF TANK?TAHNKS FOR THE IDEAS!

Man, dat zum baaaaddddd gaz. I would think with a few flushes that you would be OK. Could it be a restricted flow problem (filter, pick-up, plugged line, etc) causing the backfire (lean)??? How are you draining the tank(s)? Under what conditions does it backfire (idle, cruise, WOT)? Some more info and these guys will figure it out.

Sounds like restricted flow. The 525's will pop pretty loud when leaned out. What kind of speeds r u running? Props? stepped? I hace a 96' with 525sc's with over 300 hrs and still runs strong. I assume u have a 38'?

It I S A38,at 4000 Rmp It Seems To Be Most Occuring,im Running 25 Mirage Props,it Doesnt Backfire On Any Other Tanks,i Pulled The Filters And Found While Looking Down In It A Swirle Of Almost 2 Differant Fluids That Wont Mix,then After I Drained It The Fuel Was A Yellow Color.this Boat Was In Storage For 3 Years,the Main Tank(150gal)was Dry,the Second Tank(50gal)was Alwso Dry And The Boat Seems To Run Fine Off Of These Tanks,these Tanks Also Feed Both Motors,the Two (25gal)tanks Feed Each Motor Seperatly,it Is Only The Drivers Side That Has The Problem!i Did Find The Way The Boat Is Set Up Is A Little Differant Than A Standard 38,mine Is A P38,on The Standard The Water Tank Fill Is Located Were The Fuel Tank Fill Is On Mine And I Think Somebody Might Of Filled The Fuel Tank With Water At One Time,thanks For Helping,i Sucked The Tanks Dry From The Fuel Pickup That Feeds The Motor!

If you think it could be water, maybe an additive ( dry gas ) would help ?

How about putting it on the trailer and raising the bow as high as you can , and then trying to get the water or whatever the mystery fluid is out? May be a turkey baster (no jokes), or a syphon?

sounds like a case for lots of valvetech dry gas and stabilizer. probably have to mix few gallons of gas and do several times. Need to mix and siphon b4 it has a chance to settle. My boat has 2- 25 gallon tanks and a 150 gallon. where is your 50 gallon tank?

JJONES,
Try pulling out the sender or inspection port on that tank, tip the trailer up or down depending on which way you need to go. You can pump the bad fuel out with a small exectric fuel pump. Holley makes one that is will do the job. You can route the plastic or rubber fuel line down to the very lowest point as long as you can see what you are doing.
Be real careful with the fumes, people don't realize how dangerous they are, use caution when hooking up the electric pump and do it in a well ventilated area.
You may find water at the bottom tank.
Good luck
Post what you find and do so we all know.
Thanks Brian

thanks for all the help!