Fuel additives ???

Got a question for ya all. Would it do any good to put a gas additive into your gas tank of a hit miss like you put in your car to clean the fuel system? Something like GUMOUT or STP aditive. Just wondering if it would help clean the varnish off of sticky check valves and clean carbon off valves, clean carb orphasis and needles and such? Just wondering if anyone else has tried this with any success or whether it made there engine run poorly? Let me know your thoughts on this one. I get tired of having to clean check balls and everthing all the time.

Tom Winland Ohio

Tom, I'm a firm believer in Stabl or like product. Haven't tried STP , Gum out, Etc. Since these engines were produced before the advent of foam floats, etc. I say ----Try it. Dave in Holt.

I use and have had excellent luck and no problems with Sea-Foam. It keeps the check balls clean and the mixer orffices and needle valves clean also. It works for me!

Cheers Paul Hokanson

I have the same question? I addition does anyone know what the ingrediants are in fuel stabilizer?? It looks and smells like some other product that is worth 1/10 the price?? thanks dave from omemee

Tom,

From personal experience (cars only) the best fuel system cleaner seems to be Techron. It's marketed by Chevron (and used in their gas from the pump) but it's also available at most chain auto parts stores as well as WalMart.

I've been using it for 10 years with very good results. The local Mercedes dealer adds a bottle to the gas tank of every car (gas and diesel) that comes in for routine service checks.

It's not cheap though...about $6 for enough to treat 12 gallons

This also sounds like it could wash off the carbon buildup in an older engine and start it to haveing loss of compression and blow by. Just a thought. Joe Morris

I have found since I started using stabil several yrs. ago that rarly have to clean carbs. or check valves in any of my engines Hit&miss, weedwacker, chainsaw ect.And no more draining gas!! BobRR

stabil works well until it too goes bad, and go it does! When the fuel it is in does degrade, it makes a godawlul mess of the carb, and internal workings! As a tip - if you use it- keep the fuel tank full to to tippy top - to prevent oxidation. I do not believe it is a good idea to use a stabilizer along with a carb cleaner - the 2 chemical compounds will work against each other.

In years past I would leave gasoline in my engines, so that I could demonstrate them to visitors. This year I have been forced to drain the gas out everything that is not going to a show within a few weeks. This modern goat urine that is called gasoline will go bad in a very short time. Al Wait

I have used av gas for a long time. It doesn't do all the bad thing that automotive gas goes. Don't know how long it will last without turning to varnish and gumming everything up. I've left it in there for long period, can't say exactly but I know more than 6 months and no problem.

Good old Coleman or Wal Mart camp fuel wont go bad. Have had a bit of a rust problem with the Wal Mart brand if it drys up in the tank. Gets expensive if you run it all weekend in a big engine. D. Smith

I still use coleman lantern fuel and a little Marvle Mystery Oil. Lantern fuel is about 55 octane. When these engines were made octane was about 40. Lantern fuel doesn't seem to go bad and Marvel Mystery Oil helps lube and clean. Heard that it is the only additive the F.A.A. allows in airplane fuel.(Might get corrected that statement). Also have heard that Marvel Mystery hasn't changed since it beginning. (Might get corrected again). Don't have any references on the MM oil but do have info on the gas. LOL Fred

Gumout would do what you want, generic walmart brand is the same chemical. Mostly xylenes with some methanol and/or acetone. Stabil is only an anti-oxidant. Aviation gasoline 100LL is more refined than modern auto gas. Will never need anything added and lasts for years if kept topped off.

For removing gum and varnish, I use B-12 Chemtool. It is a xylene-type product. I use Wal Mart camp fuel in gasoline engines to avoid the revolting stink of government-adulterated fuel. It is also much more stable than pump gas. It is very dry, that is, it seems to evaporate completely without leaving any residue. I don't think there is any alcohol/methanol in it to absorb water, either. Someone mentioned adding a little Marvel Oil to camp fuel. That sounds like an excellent idea. That would give some lubricity and rust protection, and a small amount of Marvewl oil would not cause any smoke or odor problems in the exhaust. Marvel Oil has been around since these old engines were new, and it is great stuff. I wish they hadn't quit using the steel cans, not that it matters. I haven't noticed any problems from cleaning gum or carbon out of old engines, but I suppose it could happen. In a case like that, using a heavier oil, like 40W or 50W non detergent instead of 30W after cleaning the engine out would probably get you back to where you were before as far as compression. Such an engine probably needs some repair work anyway if it is going to do much running at all.

Aviation gasoline if I am not mistaken is high octane? Add this to your low tension ignition engine if you need a good work out because it probably won't start for you. High octane fuel requires a very hot spark to ignite. A spark plug engine would love it but I am afraid the 4-8 volts created by my Associated magnetos just isn't enough to ignite it. Just some thing to think about.

~Keith in Delaware, oHIo

Good point Keith, I never had an igniter engine. If I had one I would have used av gas and might have had to do a little head scratching before I figgered why it didn't start, that is if it didn't.

You know most people would think, high octane, easier ignition. Yep most haven't a clue as why high octane helps prevent pre-ignition in older cars.

I was under that the impression octane of aviation fuel was in the 80's .A friend of mine used to use it in his hit and miss engines.It also is leaded.Dick in central Pa.

I am no expert on Av gas, but I know that some of it is 80 octane, and some is higher, like 100 to maybe 110 octane. I think an igniter would handle the high octane gasoline OK as long as the vapor pressure was suitable for the engine's mixer and the ambient weather, but I haven't tried it. I have an idea that high octane gasoline could be a problem in a hot tube engine though. You would likely have to run the tube very hot to get good results.

The old engines I got don't have enough compression to run aviation fuel. Compression is not (If you're lucky) 4 to 1. Just ain't feasible to run premium or aviation fuel. A lot of people found the hard way premium and high octane fuels won't even let most of these engines start let alone run. LOL Fred