Bob Shores Eagle Hit/Miss Engine Build Thread

Are you getting WAY to much gas and it to flooded for the plug to spark?

Try disconnect the fuel line, removing the plug, spinning it up with the drill to blow out excess fuel, dry the plug off good and double check that you have spark somewhere around TDC on the compression stroke. (be sure you are spinning it in the correct direction). try to start it on just the residual fuel left in it. If it is still nothing try puting in just one drop into the intake, (or a VERY TINY bit of starting ether). See if that at least gets you some noises like it is trying to start.
 
rdean said:
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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I'm spinning it clockwise, and I believe I have the timing set that way as well.
Flyinfool said:
Are you getting WAY to much gas and it to flooded for the plug to spark?

Try disconnect the fuel line, removing the plug, spinning it up with the drill to blow out excess fuel, dry the plug off good and double check that you have spark somewhere around TDC on the compression stroke. (be sure you are spinning it in the correct direction). try to start it on just the residual fuel left in it. If it is still nothing try puting in just one drop into the intake, (or a VERY TINY bit of starting ether). See if that at least gets you some noises like it is trying to start.
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I can try that... I've tried with the carb needle all the way closed, AND without fuel, but I'll try that. I would think that even flooded, I'd get SOMETHING.
 
Update: I tried the flood solution that Flyinfool suggested. No dice there either. I ran it without a plug or carb on the drill for about 2 minutes. THEN, I put the plug back in and put a touch of gas on my finger next to the intake, it sucked up a little, but still didn't try to run at all. I also tried about a dozen configurations of the carb as well :/

I'm totally out of ideas on this thing. I re did the timing about 20 times. I've tried 2 spark plugs (both from the factory ~17 thou gap), every configuration of timing I can think of, every gas configuration I can think of, with/without the muffler, everything.
 
Did you check to see if you are getting spark at the plug at about the right time? Check it with the plug out and grounded against the head. It should spark at or slightly before TDC.

When you say you redid the timing, are you referring to the ignition timing or the valve timing?

I sure wish you were close, I would love to mess with this. There is always a reason when something don't work. The challenge is in finding it. I love a good challenge.
 
Flyinfool said:
Did you check to see if you are getting spark at the plug at about the right time? Check it with the plug out and grounded against the head. It should spark at or slightly before TDC.
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I've tried just before, just after, and AT TDC. I did check that I'm getting spark with the plug on the side of the head (not installed), and it seems to be firing immediately when the contacts connect. 1 interesting thing (that I don't think should matter?) is that the contact design fires every cycle, rather than every-other. So it ALSO fires at the top of the exhaust stroke. But thats how it is designed...

Flyinfool said:
When you say you redid the timing, are you referring to the ignition timing or the valve timing?

I sure wish you were close, I would love to mess with this. There is always a reason when something don't work. The challenge is in finding it. I love a good challenge.
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Both! I've been messing with the value and the spark plug, but I'm about 99% sure both are about where they should be. I replaced the head gasket as well, but I don't think that was a problem at all either. I've tried re-lapping the valves, I can feel suction in the intake when its running, etc. I'm just sorta out of ideas. I wish you could help too :) Hopefully it would be something simple that I'd kick myself over.
 
Wasted spark ignition is very common in 4 stroke engines. It is a lot easier to let it spark on the exhaust than it is to get it to fire every other time up. Yamaha does that on their 4 stroke engines.

Try feeding it a drop of starting ether to if something easier to ignite will hep to at least get a pop out of it.

You said you can feel suction on the intake, that is good, can you also feel pressure comming out on the exhaust?

With the plug out can you feel compression in the cylinder?
 
Flyinfool said:
Wasted spark ignition is very common in 4 stroke engines. It is a lot easier to let it spark on the exhaust than it is to get it to fire every other time up. Yamaha does that on their 4 stroke engines.

Try feeding it a drop of starting ether to if something easier to ignite will hep to at least get a pop out of it.

You said you can feel suction on the intake, that is good, can you also feel pressure comming out on the exhaust?

With the plug out can you feel compression in the cylinder?
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I'll try both of those!

1 more thing I decided to try, is my ignition system supports 3-6v. I've been running on 2 AA batteries (which came with it), but I ordered a 6v NiMH battery to try out as well. Perhaps it'll do a little better.
 
Video attached with the pump like sounds not makes when I spin it. I feel exhaust pressure, but I can't get a finger on the spark plug.

I'm using an evolution 1/4-32 spark plug. I noticed googling he calls for a 15 thou gap (I'm a little higher), so I tried that and no improvement. I tested the plug in the head (backed it off a few turns on the bolts) and confirmed I'm not shorting there either.

I also tried butane sprayed into the intake, but got no change.

It is just super odd to me... I would think even a flooding would give something resembling combustion, but I'm getting nothing of the sort.
 

Attachments

  • VID_20200819_143203.mp4
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Just tried a 9 thou gap as well, nothing again.
 
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