Ok please bear with me. I am totallynewto this. I watched a video on YouTube then went and built a potato gun. Its all PVC with with a grill igniter. I loaded it and sprayed starter fluid in, screwed on back hit igniter several times and nothing. After I took the back off I did eventually get it to catch fire inside combustion chamber. I don't knw what I'm doing please give ,e some guidance.
Posted: Tue Oct 11, 2011 11:01 am
by Moonbogg
Probably using too much fuel. it takes only a quick spray and thats it. Try venting the chamber with fresh air and then do just a single, quick spray. People tend to think that by adding tons of fuel it will be more powerful. All that will do is starve it of oxygen and it won't fire.
Posted: Tue Oct 11, 2011 1:09 pm
by Kdmann64
Good call, I got it fire. It's jot firing every time though. In think my combustion chamber may be too small or my igniter sucks. But at least I can make it fire. It will be a constant work in progress.
Posted: Tue Oct 11, 2011 1:23 pm
by jackssmirkingrevenge
here's a helpful pointer in the right direction
[youtube][/youtube]
the size of your spark gap might also be an issue.
Posted: Tue Oct 11, 2011 1:30 pm
by 03cumminsguy
Sounds like too much fuel to me as well. Think Charmin "less is more"
Posted: Tue Oct 11, 2011 2:59 pm
by saefroch
Meter. Spray 'n' prays are inherently unreliable... hence the name.
EDIT: Fixed for most epic typo ever.
Posted: Tue Oct 11, 2011 3:04 pm
by jsefcik
try adding in a chamber fan to help venting, i put one in my spray and pray and helps alots, never had a miss fire!!
Posted: Tue Oct 11, 2011 3:34 pm
by Kdmann64
Yeah my spark sucks, it's jumping all around and not going the way it is supposed to
Posted: Tue Oct 11, 2011 4:31 pm
by Gun Freak
Spray 'n' prays are inherently reliable
lolwut
Posted: Tue Oct 11, 2011 4:43 pm
by mattyzip77
try aqua net hair spray for a full 5 second blast of it into the chamber. My bet is your using way too much fuel or to little. Also the potato gotta be packed in the barrel so its air tight. good luck n let us know how you made out!! You do not need to add a fan, and your spark gap should be 1/4 of a inch to 1/2 of a inch. Are you using screws for your spark electrodes????
Posted: Tue Oct 11, 2011 4:49 pm
by saefroch
Doesn't matter where the spark is, so long as it's there. Middle of the chamber is ideal, but the difference is relatively small.
Posted: Tue Oct 11, 2011 5:27 pm
by Kdmann64
Where can I get a better spark generator. Mine is really rigged up and sucks actually.
Posted: Tue Oct 11, 2011 5:50 pm
by mattyzip77
try a flint sparker from a camping lantern, like 4 bucks at walmart, but a grill ignitor is 100 times better and should work!!!
