SeaKing

Ron Boyle

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Joined
Mar 5, 2006
Messages
14
I have a '73-'75 SeaKing 5 horse motor. It wasn't getting what I thought any "fire" coming from the spark plug. Since that time I've replaced the coil, condenser, points, and a new plug. I have a faint shock when holding the plug in my hand but no "ark" across the electrode of the plug when spinning the motor. All the wires are connected properly; points are set properly; plug set properly; and no wires being grounded out. The bottom line, it won't start. BTW, it has clean gas and I used starter fluid.<br /><br />Ron
 

WillyBWright

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Dec 29, 2003
Messages
8,200
Re: SeaKing

Welcome to iboats. :) <br /><br />Sounds like you covered all the bases. That leaves a weak flywheel magnet. Have a look and see if there's rust between the laminations. That kills them.
 

steelespike

Supreme Mariner
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Apr 26, 2002
Messages
19,069
Re: SeaKing

If the flywheel key or keyway is damaged it could throw off the timing between the flywheel magnets and the points causing a weak out of time spark.Also be sure the stator is not wobbly and the coil is placed correctly.
 

Texasmark

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Dec 20, 2005
Messages
14,778
Re: SeaKing

Agree on both points. If the laminations of the magneto are shorted, it will put out a weak spark due to excessive eddy currents (loss) within. Cleaning off the surface probably won't help as the problem will be lam to lam and you can't see down in there without disecting it.<br /><br />The Woodruff key aligning the flywheel has to be perfectly square. Remove the flywheel nut and look down at it and if it is partially sheared, from a timing point it is as good as sheared. BTDT. <br /><br />But, I'm going to go for the lams in the mag because the woodruff key has nothing to do with weak spark. It only causes the spark to arrive at the wrong time if damaged or broken. BTDT<br /><br />Mark
 

JB

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Mar 25, 2001
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45,907
Re: SeaKing

How about a model number so we know what you are dealing with, Ron.
 

Ron Boyle

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Mar 5, 2006
Messages
14
Re: SeaKing

JB<br /><br />These are all the numbers I have:<br /><br />Sea King J 500 11068<br /><br />S/N 35 3440 60 27005<br /><br />Year 70-71
 

Ron Boyle

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Mar 5, 2006
Messages
14
Re: SeaKing

As I mentioned, I have a brand new coil. It was doing the same with the old one. Everything is tight. No slop in the flywheel or keyway. No corrosion on the flywheel. Points are new and set properly. I put a new condenser in as well. "No visable spark in the sparkplug when spinning the engine.<br /><br />Ron
 

Ron Boyle

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Mar 5, 2006
Messages
14
Re: SeaKing

JB.......correction on those numbers:<br /><br />Mod # J500 1106B<br />Type: 60 27005R<br />S/N: 35 3440<br />Year: 70-71<br /><br />Thanks, Ron
 

Texasmark

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Dec 20, 2005
Messages
14,778
Re: SeaKing

Ok only one thing left. <br /><br />The magneto is just a coil of wire wrapped around some thin, insulated, soft Iron laminations. As the magnet on the flywheel passes the coil it introduces a current in the coil which produces magnetic flux which is energy...vit...(Volt-Amps-waiting for the time to be released)....Lenz's law or Maxwell or one of those smart guys of ancient times....<br /><br />Anyhew, to get current to flow in the coil, the circuit must be closed (a complete loop). <br /><br />The closed circuit comes from the points (tied to the flywheel...mechanically and supposedly electrically) which, at the proper time, close and tie one side of this coil to engine chassis (ground).<br /><br />This causes the other side (of the magneto) to immediately provide high voltage to the cap of the plug which builds higher and higher until it jumps the plug's gap and you have ignition. (All this takes place in thousandth's of a second)<br /><br />The energy in the coil of the magneto is dissipated in the heat of the spark across the plug's gap. <br /><br />Now if you have 2 or more gaps, you have to overcome both and usually the magneto is not that powerful. <br /><br />Where do you get 2 gaps? Corrosion in any part of the conduction path.<br /><br /><br /> Hence the points are attached to the flywheel which is attached to the crank, which is tied to the engine block by either internal sleeves or roller bearings, from the block to the threads of the plug thru the plug to the high voltage lead and back home.<br /><br />If current can't flow it will not work. On an engine that old, the "insulation" preventing current from flowing could be anywhere I mentioned. Any interface<br /><br />Point to flywheel mating surface and or screw threads.<br /><br />Flywheel to crankshaft<br /><br />Block to plug threads.<br /><br />All are dissimilar metals in contact with one another, carrying current (electrolysis) and aluminum is involved which loves to corrode.<br /><br />Clean up all your interfaces and see if it doesn't improve things.<br /><br />Mark
 

BillP

Captain
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Aug 10, 2002
Messages
3,290
Re: SeaKing

Recheck you wire connections and make sure they are correct. About 30 yrs ago I bought a 1940 SeaKing single cyl that the seller couldn't get spark on. It was otherwise in A1 condition so I bought it for $25. I popped the flywheel off and found a wired hooked up wrong but it "looked" right if you just glanced at. I can't remember exact details but I think it was the points or condenser not being grounded properly. Anyway that took care of the problem. It's a long shot but worth a double check.
 

WillyBWright

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Dec 29, 2003
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8,200
Re: SeaKing

Looks like a Clinton number. They made those for Wards. Single cylinder, air cooled. Check the shut-off to make sure it's not shorting out.<br /><br />This probably isn't it, but look for extreme wear on the points cam. Or rust. Rust can wear-down the arm of the points quickly and leave no gap. But that takes a few minutes of running.
 

Ron Boyle

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Mar 5, 2006
Messages
14
Re: SeaKing

hmmmmm, as I mention; I bought a new coil, points, condenser, and the bracket it all mounts on from "Discount Marine Parts." The points are set at 20 thousands; the fly wheel is clean with no corrision or oxidation anywhere. The wiring is new and correct. The spark plug is new as well. NOW, the motor responds the same now as when it had to old parts. I can feel (with my hand) some fire/spark in the plug......but no ark is present when I spin the motor.<br /><br />Ron
 

Texasmark

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Dec 20, 2005
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14,778
Re: SeaKing

Okay. Do you have an ohmmeter? If so, measure the resistance from the coil wire "terminal" (that connects to the points) to the metallic shell of the spark plug....with everything hooked up and the points closed. You should read like .4 ohms for your lead resistance and not more than 1 ohm additional for circuit resistance.<br /><br />Then go to the flywheel and take a screwdriver and see if the magnet sucks the screwdriver in indicating that you have a good magnetic field. <br /><br />Then how far is the magnet from the lams of the coil. Never worked on a Clinton, but most magneto's are about the thickness of a grocery store paper sack from the flywheel.<br /><br />Let us know your answers.<br /><br />One last thought. How do you stop this engine? Do you shut off the fuel via a throttle, or does it have a kill switch, pushbutton type of thing. If it has a kill switch, there will be(should be) an additional terminal on the coil. Disconnect the wire from this terminal and see if it will start. If it does, your kill circuit is shorted out somewhere.<br /><br />Mark
 

mfbear

Petty Officer 3rd Class
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Mar 22, 2003
Messages
77
Re: SeaKing

I checked a Sea king service manual I have on J motors and the first thing it mentioned was compression. You might want to check that, if you don't have enough it won't fire. Sounds like you have checked about everything else. My K900 sometimes won't fire either I found if I lightly sanded the inside of flywheel it would fire right up. Most times every looked fine but guess not.
 

Texasmark

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Dec 20, 2005
Messages
14,778
Re: SeaKing

Ok mfbear. Compression has nothing to do with fire. Lighting off and running, yes, but fire, no.<br /><br />Would you elaborate on your sanding the inside of the flywheel. You may be onto what I said about needing a ground return path to the plug that is not corroded up due to age.....even though it may not be visable to the naked eye from outside prior to disassemby. The ohmmeter check, however would tell the story.<br /><br />Mark
 

mfbear

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Mar 22, 2003
Messages
77
Re: SeaKing

Texasmark, I said the manual said compression, this is the exact quote from manual "The energy required to fire a spark plug under compression depends on the compression, the spark plug gap and the circuit conditions." end quote.<br />As to sanding the flywheel I found when my Clinton would not fire that if I sanded the entire inside of flywheel not just the magnets with 120 or 180 grit it would fire. Did not see any rust but must have had slight film that I could not see.
 

mfbear

Petty Officer 3rd Class
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Mar 22, 2003
Messages
77
Re: SeaKing

Just looked again and think that motor is suppose have some sort of kill switch as it should have a shorting wire.
 
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