1973 9.5 johnson coughs and dies out

dfrants

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Jul 26, 2008
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picked up a real clean looking 1973 9.5 Johnson. She starts and runs but will cough and die after a minute or so. adjusting the rich/lean doesn't help. took the carb apart expecting it to be dirty but it was clean. replaced the plugs, fuel pump, valve needle, coils, points and condensers. still runs the same. I missed something. at a loss. seems to smoke too much even at slower speeds(before it kills). plugs are wet with fuel.
 

dfrants

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thanks, found it.
Also noticed that at one time the head gasket was replaced. could that be an issue?
 

tomhath

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Dec 5, 2007
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814
Sounds like it's flooding out. Is the float adjusted correctly? Try it a bit lower.
 

racerone

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If spark does not jump a gap of 5/16" or better you have ignition problems.----Easy to test.------Pull the flywheel off.-----You will find 2 cracked coils or 2 newer replacements already.
 

ultra353

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Jun 21, 2009
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Make sure the 3 microscopic holes in the carb throat are clean. Their your idle circuit. There hard to see , shine a light down the the throat and you'll see 'em. Spray carb cleaner through all the passages and you should see it come through those holes.
Could be a bad carb, I had one on a 9.5 that I must have cleaned 10 times, same result. Put a known good carb on and ran perfectly.
Could be Leaky crank seals, crankcase halves leaking, check your compression for even #. Plus what others have said above
 

hardwater fisherman

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Mar 19, 2010
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If spark does not jump a gap of 5/16" or better you have ignition problems.----Easy to test.------Pull the flywheel off.-----You will find 2 cracked coils or 2 newer replacements already.

He has said he replaced several things including coils.
 

dfrants

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just did a spark test...I believe it is a weak spark problem.
 

hardwater fisherman

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Mar 19, 2010
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You said you replaced the points. Did you also clean them? And are they correctly gaped? Did you remove the mag plate to properly screw the plug wires in the new coils? Also you could clip a little bit off the ends of the plug wires and reinstall the springs and boots.
 

dfrants

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Jul 26, 2008
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thanks for all the tips....went back all double checked everything, did the snip the end of the wire trick and made sure the points are clean gapped that .020. still no luck. thinking one of the components is defective. or I somehow fried it. ordered a new ignition kit.
 

dfrants

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Jul 26, 2008
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what are the little red capsules included in the ignition kit for? cleaning the points?
 

Crosbyman

Rear Admiral
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Nov 5, 2006
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it is grease not oil. oil comes in a can this capsule is just like a pill you pull it apart and squeeze the grease out for the point pivot posts

the felt rub pad is oiled with 2-3 drops
 

hardwater fisherman

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Mar 19, 2010
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It may very well be grease. But I do know that the Sierra ignition kit I ordered last year had oil in the capsule and not grease.
 
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