Strike Rate

[mike_is]

This is my first spud gun so excuse me if i don't use the correct terminology

Basically, it's a typical spud gun for beginners, the Ignition system is just a square hole, big enough to fit a BBQ lighter.
1) after putting the potato in, i spray the combustion with good smelling gas
2) screw up the bottom cap
3) insert the BBQ lighter
4) light away
But... It doesn't seem to work, it has worked 3times out of 20trys (all the times it worked, it has gone about 70m), and they're probably either luck or we did something out of the norm. any who I'm ask how can i increase the strike rate of making her work?
I was thinking about drilling a hole for oxygen to be able to mixed in with the gas thing(sorry lol).
Just some info, the combustion is about 40cm long and the hole for the BBQ lighter is roughly 15cm from the bottom cap.

Thankyou in advance, once again, sorry about not using the correct terminology

[TwitchTheAussie]

Its probably just your "ignition system". Get a BBQ lighter replacement, sleeve the chamber or get a new one and put two screws in and hook the wires to it. Also a chamber fan helps.
Another problem you could be having is too much fuel and not enough air. Yet again a chamber fan should help that. Either way just restart you chamber and you'll be right.

[hi]

like aussie said, you probably have too much fuel. If you are using deodorant, then about 1 to 2 seconds is probably enough. any more and it just wont work.

EDIT- when i made my first i developed a technique that work very well and was almost, not quite but almost, as powerful as a mid-size mapp gas cannon. what i did (i used axe as fuel) is i put the tater in, then would up-end the cannon (so that the barrel is resting on the ground) and open the cap, then spray in about half the fuel (about 1/2 second), then put the cap on, not screw it on, just cover it for about 3-4 seconds, then open it and spray another second or so. this worked VERY well and was VERY effective. you might want to try it.

[Bubba05]

Cheak your spark? and go easy on the fuel.....You can "flood" these things. the propelant could also be powdery if you know what i mean? try and get a deoderant that is "wet" and you should be rite!!

Bubba!

[Smiley]

I am having the same problem. Is the loctaion of the sparker important or is the mixture just not right?

[Pete Zaria]

The #1 cause of combustion guns not firing is people use too much fuel.

Honestly, 1-2 seconds of aerosol whatever is usually enough. Half a second spray of carb starter fluid worked for me when I still used spray propellants.

TRY LESS FUEL! Try other types of fuel.

A chamber fan, as others have mentioned, helps to mix the gases in the chamber, induce turbulence, and all-around enhance combustion.

Move up to metered propane and you'll never have that problem again...

Peace,
Pete Zaria.

[Bubba05]

@ Smiley yes and no. you have to make sure your not spraying the ignitor coz that can cause no go too.
Where abouts have you got the ignition mounted?

Bubba