Bob Shores Eagle Hit/Miss Engine Build Thread

Flyinfool said:
That exhausts my ideas for now. I hope the new one works out, I am as anxious to see this run as much as you are.
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Yeah, I decided to stop trying to cheap out on this electrical system. The nice part is the new system is 6v, so I only need 4 AA instead of 8 :) So I'll have backups! I was still doing ~12.5v when I gave up btw, for anyone interested.
 
Hmmmmmm....
I wonder if AA batteries just could not supply the amps needed for a strong spark??? Try connecting to a lead acid battery just for testing?
I had to build an ignition system for a model aircraft and it took a healthy battery to make it work.
 
Flyinfool said:
Hmmmmmm....
I wonder if AA batteries just could not supply the amps needed for a strong spark??? Try connecting to a lead acid battery just for testing?
I had to build an ignition system for a model aircraft and it took a healthy battery to make it work.
Click to expand...
Not a bad thought. I might give it a try if the shipping from the UK takes too long :)
 
We made a see's candy shock box with motorcycle coil and vibrator from old tube radio.

Required d cells.

If 6 volt coil use 4 d batteries.

If your points has not great contacts then it also may be poor.

For rpm of this engine a relay can be used controlled by points to allow for higher switching current.

Transistor works too but relay may be handy, for testing anyway.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
Good News:
Alright, the ignition came today, and the good news is it works! Even with the old spark plug. SO, I guess it was the ignition. Even off of only 3 volts, I got plenty of spark, so I'm pretty sure that part is done. Additionally, it is much smaller/neater of a package.

Box it came in:
IMG_20200811_143511.jpg


AND installed, it only took a few minutes! The +/- battery connections go in two of the screw-terminals, and the contact goes in the other. I'd already had the contact wires done, so that was not a problem.

it ALSO came with a separate ground wire (likely for the spark plug, which I just hooked up to the edge of the motor for now. The one downside is the spark-plug connection is an alligator clip, rather than something nicer. Otherwise, it worked a charm! It says it can go from 3-6v, and the battery pack it came with uses 2 batteries, so I'm at ~3.2v.
IMG_20200811_144732.jpg



Bad News:
No Fuel. The carb doesn't seem to be carburating. My check valve is doing something odd as well, I manually 'sucked' fuel up, and it seems that the check-valve keeps a vacuum behind it, but doesn't stop the fuel in front of it from going 'down'. I'd tested it in advance, so I don't know what is wrong with it.

That said, the carb isn't sucking fuel at all. Do I just have to figure out how to get the check-valve to do its job and 'prime' the carb in some way? Anyone have ideas? Or did I just screw up making the damn'ed carb?
 
Glad to hear you got the ignition figured out . Can't even make a suggestion on the carb
 
You could plug the carb inlet with your finger and then turn the flywheel briskly 1/2 turn on the intake stroke it should suck gas into the engine.

Ray
 
rdean said:
You could plug the carb inlet with your finger and then turn the flywheel briskly 1/2 turn on the intake stroke it should suck gas into the engine.

Ray
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This actually worked for getting fuel in! I still couldn't get it to fire though, it didn't seem like it was trying. I might have to give setting the timing another try next time I'm feeling up to it.
 
I'm completely out of ideas now. I spent two solid afternoons, 3-4 tanks of gas, and 1 bench fire trying to make this thing work, and it won't even make an engine noise. I've tried messing with the carb needle, I've tried messing with the exhaust valve opening, I've tried messing with when the spark happens, I've tried everything I can think of. I drew out the 4 cycles of a 4 cycle engine to double check, and nothing.

So far, I get ZERO engine noises/behavior/etc. I've tried running it with my drill as well! I have compression, I have spark, and I have fuel. I can tell fuel is getting into the cylinder, as I am getting ring-blow-by after running it with the drill for a while.

I'm about 99% of the way to just throwing this damn thing out, and never trying again :/

EDIT: I even removed a few coils from the intake valve spring, I can see it moving, and it seems to seal. Just nothing that even resembles combustion.
 
This may sound silly but you have the engine in from of you with the head on your left hand side. You spin the flywheel with your right hand is it CW or CCW?

Ray
 
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