White Gas in Gas Hydros

[FlyinFinn]

OK, I am a relative newbie to the GAS boat scene and i have questions regarding the NAMBA rules on fuel for gas hydros. A member of my local club is running white gas, or Coleman fuel, in his gas hydro with 8 ounces per gallon of Amsoil of some kind. A few reasons he likes this is that there is no stinky gas smell, white gas is very clean burning, and the diaphrams in his zenoah carburetor last much longer. Now, I heard white gas has a octane rating of 55 or so and gasoline of course has much higher octane ratings like 85 to 120 or so. My question is : is white gas legal with regard to NAMBA rules? Also, to run white gas, what modifications would you need to make to a Zenoah motor to run it well?

Jeff

 

[j whiddon]

Its NAMBA legal and no mods necessary.

 

[Andy Brown]

I hold the IMPBA LSG36cc Oval record using Coleman in a QuickDraw 30.5cc engine.

Back to back test showed no difference in speed. A very small adjustment to the needle valve was required.

 

[Bradley Maglinger]

I like Crown Camp Fuel, no issues winning heats with it, and it only $8.99

https://www.academy.com/shop/pdp/crown%C2%AE-camp-fuel#repChildCatid=26114

 

[FloridaScaleBoater]

I hold the IMPBA LSG36cc Oval record using Coleman in a QuickDraw 30.5cc engine.

Back to back test showed no difference in speed. A very small adjustment to the needle valve was required.

Andy,

The small adjustment, are you going richer or leaner?

Hi needle or low or both?

 

[LohringMiller]

We did a comparison of legal and illegal fuels and oils on an M&D Zenoah. We only compared power. Below is the full article.

Lohring Miller

Gasoline and cheating.pdf

 

[photohoward1]

Can’t open in taptalk

Sent from my iPhone using Tapatalk

 

[GeraldClark]

I am interested in getting into gas boats. I do not like monos. With that said what would be the best class to start out with. I ran .21 outriggers in Germany.

 

[Dennis Somers]

Finn, white gas ( Coleman ) is a good choice for most of our marine gas motors. Higher compression billet models may need more octane.

The reason people may worry about low octane is detonation damage. Two things that detonation need to exist are time, and space. Mostly detonation developes at lower RPM and high loads. Our engines idle at 6 to 8K ( redline for a lot of other engines ), and run 90% of their time at 18 to 20K+. Our combustion chambers are around 1.2 to 2cc. and a 10mm. plug takes up a lot of that. Detonation is 2 or more flame fronts developing within a chamber, that collide to produce uncontrolled violent explosions. At 18 to 20K, inside that tiny chamber, there is no time or space for that to happen, UNLESS other criteria are out of whack. Overheating, advanced ign. timing ( most of ours are pre-set ), lower speed lugging from a too-large prop, or lean mixture from settings or restricted fuel flow, can cause detonation, outside of the octane requirement.

A lot of modellers look at octane and relate it to other much larger motors. Our little gassers are in a field of their own. Those larger engines run much lower RPM, and their combustion chambers are huge ( giving them the time and space ).

I hope that helps to understand "why".

 

[Dennis Somers]

Mr. Clark, if you want to wet your feet in gas boats and don't like monos, the gas cats are fun. I would suggest you get a stock Zenoah of whatever displacement would fit into a given race class in the future. It can be modded by any number of guys afterwords, if that's what you wanted. The stock motor would get you used to the gas boat handling, as well as the general use and maintenance of the gas motors, at a fraction of the modifieds. In some cases, you can use the same props and have them pitched up as needed.

 

[Ron Olson]

I've been running Coleman fuel for years. No additives for a cleaner burn, no nasty gas smell, a shelf life that's very long, possibly years and I didn't have to touch a needle from gas. The only downside is the price compared to pump gas. The best price I found on it locally is at Menard's, cheaper than Wal-mart. With pump gas I was constantly changing diaphragms in the carb because of ethanol.

 

[DON MAHER]

Hey Ron,

I to ran Coleman for long time. I have made the switch to Crown with no difference, but the price, about half!

 

[LohringMiller]

I am interested in getting into gas boats. I do not like monos. With that said what would be the best class to start out with. I ran .21 outriggers in Germany.

Contact the Voodo club and see what they run. Carlo Catalanotto is CC Racing Engines and should know what's popular to run. Gas riggers are a lot larger version of your rigger but run the same way. I think you will find that gas boats are the most popular in your area.

Lohring Miller

 

[Richard Hartley]

Pump Gas