Weak Spark

[Rkymtn57]

1956 J Qd-17 10hp.

Is it possible to see spark on a tester , but it be weak enough not to ignite a lubricated starting fluid or gas sprayed into the cylinder ?

It wont even pop.  I can see the plug firing when laid against the powerhead ?

How can i improve spark after completely rebuilding the coils , condensers , points  , ive learned how to set the points correctly everything is wired correctly ???    Thank you , D

 

 

[green-thumbs]

Compression, Carburetion and Ignition, a motor that has all 3 has to start. Does REBUILD mean all new ignition parts or something else.

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Rkymtn57

[fleetwin]

OK, well laying the plug against the block and looking for spark is not the most accurate way to test.  Usually most OMCs with universal magnetos should be able to jump a 1/4″ air gap.  So, if you were to report that the spark jumped a 1/4″ air gap, then I would be more inclined to say that spark is not your issue.  But, just because it jumps the small spark plug gap does not guarantee it is doing that inside the combustion chamber under compression.

So, the engine doesn’t even pop, or try to fire?  Are you sure you have the wires on the right plug, easy to mix that up.  How about if you prime the cylinders through the plug holes with some fresh fuel/oil mix, then try cranking it…

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Rkymtn57

[David Bartlett]

Are the spark plugs new? Correct for the application?

David Bartlett
Pine Tree Boating Club Chapter

"I don't fully understand everything I know!"

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Rkymtn57

[Rkymtn57]

Green-thumbs , yes just all new ignition parts.

Yes , Fleetwin   fuel in plug ports  , upper wire to upper cyl.

David , Yes , new plugs.

Magnet in flywheel is strong and looks good.  Ive gapped it with the coils as close as possible.

???

[Rkymtn57]

The old plugs in this motor are Champion J4C

The recommended plugs on Marine Engine are RJ8C or J8C.

The cross reference i found said , NGK R    BR6S

Am i wrong ?

[elgin2]

Front coil to top cylinder. Some new omc points don’t adjust correctly or at all. Make sure the points move when trying to adjust.

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Rkymtn57

[labrador-guy]

Well here is my two cents on this problem.  Are your points clean?  I mean new points that have been cleaned and polished?  Points come with some kinda gunk on’em the contacts must not be touched with your finger or anything else but a feeler gauge.  Condensers new?  I have been having problems with new condensers that are junk.  If all this is well I would tape the plugs to the side of the block and spin the motor with an electric drill.  There is something going on in the ignition systems that a mechanic has to get the polarization correct.  There are people on this website that can explain polarizing better than me.  Hope this helps!

dale

get’em wet…don’t let’em set

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Rkymtn57

[Steve Martin]

Make sure the points cam is not upside down.

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seakaye12

[fleetwin]

J6Cs are the correct plug for this engine.   J8Cs are too hot.

Nonetheless, the engine should start up just fine on the J8Cs.

Again, the engine makes zero attempt to fire/pop/putter, anything, correct?

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