Symptoms of bad gas ?

[infotraker]

The Sanger hydro 468 BBC is acting up badly. NYD at CFW it started running bad, backfiring when slowing down to idle. thought there may have been water in the gas so added stuff to get rid of the water. Next time out it ran worse (2 months later). Would quit when put into gear. Put new fuel filters in , ran better but would not run faster that about 3000 rpm. Gas may be the problem, I'm also rebuilding the 750 holly carbs. Guess i'll siphon out the 91 octane and put in new fuel. Can bad gas (old) cause these probs ? I need to get it running this week as going to Eagle Lake for a weeks vacation. I know we just got back from a 2 month trip to Alaska but gotta get out in the boat !

[vdrivedenis]

I have a one month rule with my Ultralight Airplanes. The new gas with menthanol or alcohol in it is eating our gas lines from the inside out, and will sour in as little as one month. I recently had a fuel line discenigrate that looked perfectly good from the outside-this happened shortly after I landed! I have noted that the current Avgas is also going sour almost as quick. I have a beater forklift that will run on anything, and is the reciprient of all of the gas that is over one month old. I do not store gas anymore either. See if your fuel lines have rotted on the inside and if any of that mess has made it to the carbs.
Good luck,
Denis

[Terminal Velocity]

The Sanger hydro 468 BBC is acting up badly. NYD at CFW it started running bad, backfiring when slowing down to idle. thought there may have been water in the gas so added stuff to get rid of the water. Next time out it ran worse (2 months later). Would quit when put into gear. Put new fuel filters in , ran better but would not run faster that about 3000 rpm. Gas may be the problem, I'm also rebuilding the 750 holly carbs. Guess i'll siphon out the 91 octane and put in new fuel. Can bad gas (old) cause these probs ? I need to get it running this week as going to Eagle Lake for a weeks vacation. I know we just got back from a 2 month trip to Alaska but gotta get out in the boat !
With this statement i'd check your timing as well. I had a distributer come loose once and i chased a similar situation for weeks. I've also seen the lead on the rotor come loose and move inside.

[jimthetoolman]

How many pounds is your fuel pump pump putting out? You might want to check that. Had the same problem.

[Willis]

This kind of filter will help
81794 High Performance Filter Head
• High Performance up to 25 GPM
• Dual Inlets and outlets allows choice of flow direction
• Ideal for dual fuel pumps or dual carburetors
Kit features cast aluminum filter mount, Perma-Cool®24,000 mile filter element, two pipe plugs.
Port size:1/2 NPT(int)
http://img.villagephotos.com/p/2002-10/61269/PerMaCoolWaterFuelSeparater.jpg

[infotraker]

Put new fuel in. Rebuilt both carbs. Started engine, flames in both carbs, put out the flames with a rag !. Reset the floats and no gas overflow but still some backfire. Adjusted the roller cam valve setup, some were off a bit. Started the engine again and checked the timing. Should be total of 38 degrees with 13 showing on the crank. Way retarded, reset and things got very much better ! Starts quick, no backfire and ready to go to Folsom in the morning for test run ! # days till leaving for Eagle Lake. Hope it runs or I'll have to take the backup 68 Schiada flat this year.

[DUCKY]

I was just going to say that your problems sound like late timing. If you have points, you should check the dwell. It should be right around 30-32 degrees for single points. If you have a dual point distributor, you can either adjust one set for about 20 and the other for 12-15 (best for high rpm) or set the distributor up to run off of one set, and set them both at 30-32 then check the timing on each set of points individually and mark the distributor/manifold accordingly. Many people do it this way so if you happen to burn a set of points, you can swap to the other set with almost no tools in a couple of minutes.
PS, if just a reminder, if you do have points, you must use a ballast resistor, or resistance wire to keep the points alive.....