Engine won't stay running

mattss

Cadet
Joined
Jan 5, 2014
Messages
6
Engine was running fine. Sat a week and then start and stop
Put new kill switch in same issue, start and stop. 2nd try ended no spark at plugs. Today I bypass kill switch, and start and stop. Difference is have spark to cylinders. Won't start
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,612
contaminated fuel? Fill a glass jar and let it set -- any water will settle at the bottom.

[DUPLICATE POST]
 
Last edited:

CaptnKingfisher

Petty Officer 1st Class
Joined
May 14, 2017
Messages
259
What does "start and stop" mean, how long did it run for before stalling each time, a couple seconds?

I'm still suspicious of the ignition circuit. 1st you had a Killswitch that you suspected went bad, then wired a new Killswitch and still had a no spark condition. Bypassed switch and saw spark and assumed it was fixed. I would spend some more time going over the ignition circuit and verify you are consistently getting strong spark. If it's not a spark issue start diagnosing fuel. Inspect and clean fuel lines, filter, verify good gas or try a second tank that you know is good. Spray a little gas into the carb and crank. Let us know what you find
 

JDusza

Ensign
Joined
Apr 21, 2009
Messages
981
66 views with 2 responses. Woefully inadequate.
What engine are we talking about? What's your serial number?
Disconnect the kill switch circuit to leave it out of diagnostics. It's confusing you. Leave it out for now. If by some miracle the engine starts and runs you can kill it by choking it.
Have to go back to basics:
Fresh, clean premix fuel on hand for when you're ready for it. Put it aside for now.
Compression test should show greater than 85 psi. You are probably okay but good to know as a gauge of power head health.
Air gap spark test (must jump 3/8" air gap), cleanly and consistently.
As per CaptKingfisher, you need to verify solid ignition before you go any further. Forget the kill circuit, disconnect it. It's confusing you. Forget the carburetor, you're not ready to evaluate it yet.
Put a timing light on the spark plug wires. Easy test. Mark the flywheel at each cylinder TDC. Find TDC by using a little straw in the spark plug hole feeling the piston arrive at the top of it's stroke. You ight be able to see it with a flashlight. Mark the flywheel for that cylinder 1, 2, etc... Remove the park plugs and ground them to the engine block with a little wire, so there's no compression, no chance of starting and no damage to your electrical components. Spin the engine with a drill attached to the flywheel. Look at each cylinders timing results: no firing, misfiring, crosstalk, etc... Each cylinder signal should be clean and consistent, no random flashing stuff. This will tell you the next level of symptom and where to go troubleshooting.
Only when you have consistent ignition operation do you move on to the fuel system.
Post results so we can help you.
J
 
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