HELP! I can't get my 3 HP Briggs to start

#1
hey folks, I'm starting a new thread since my last one was specifically about diaphragm functions. I am trying to trouble shoot my Magnetron 3HP Briggs 80202 that won't start. I just installed a new diaphragm and carb to tank gasket thinking that would get it running. I also cleaned the carb and tank thoroughly checking all the passageways with wire. Next I pulled the flywheel just now to confirm that the woodruff key is in place and not sheared. I have also confirmed that I have healthy spark. I tried a few eye droppers of fuel down the spark blug hole to see if it would run for a second and that hasn't worked either. I don't have a compression tester at the moment but I'm wondering if that may be my issue. I can easily turn the engine over with my hand if the pull start is off.

In theory I have fuel air and spark so I dunno? Any suggestions as to what I have overlooked are much appreciated, thanks!

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#2
Update: I'm able to spin my intake valves with my fingers regardless of where I am in the stroke of the engine. This leads me to believe that the intake valve isn't ever closing. I don't have feeler gauges but am going to grab some tomorrow. I'm not sure this is my only problem as I imagine the engine still would have fired but ran poorly if it was the only thing wrong? Either way I bet ill end up grinding the valve down once I get it apart. Anything else that could be the culprit?
 
#3
I got a set of feeler gauges at Harbor Freight for I think 5$, I had a similar situation on my 5 hp, it had fuel, spark and compression. Finally realized the key was sheared, still wouldn't start. Ended up being my spark plug gap was too small, lol.
 
#4
I got a set of feeler gauges at Harbor Freight for I think 5$, I had a similar situation on my 5 hp, it had fuel, spark and compression. Finally realized the key was sheared, still wouldn't start. Ended up being my spark plug gap was too small, lol.
hmmm i wish it was just my plug gap! I checked it earlier since i do have a lil plug gauge but not the thinner blade style for valves.
 
#7
Yes, timing is fixed, more or less, but, if the coil is installed backwards, it will be 180 degrees out. Additionally, the gap between the coil and the flywheel must be right. There are some good You Tube videos of setting the gap. But, here's a quick and dirty method. Get a business card, or something of similar thickness, bring the flywheel magnets around to the coil. Loosen th coil and lift it up. Slide the card under the coil contacts and let the coil set on the card. Now tighten the coil mounts. Turn the flywheel and remove the card. Have you known this engine to run?
 
#8
Yes, timing is fixed, more or less, but, if the coil is installed backwards, it will be 180 degrees out. Additionally, the gap between the coil and the flywheel must be right. There are some good You Tube videos of setting the gap. But, here's a quick and dirty method. Get a business card, or something of similar thickness, bring the flywheel magnets around to the coil. Loosen th coil and lift it up. Slide the card under the coil contacts and let the coil set on the card. Now tighten the coil mounts. Turn the flywheel and remove the card. Have you known this engine to run?
Hey thanks for the tip n the coil gap! Sounds like a good thing to check. I ended up getting the engine to run! The problem was my intake valve. The gap was non existent to the point where it never closed. I ended up filing the valve by hand until the valve lash was right and it fired up first try after reassembly. My assumpting is that due to the valve leaking there was not enough compression for combustion

Next I need to pick a gear ratio, buy a clutch and sproket and start building. I have some 15inch trailer wheels im hoping to use. I prefer good low end to to a high top speed, any tips are appreciated.
 
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