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April 5, 2024 at 12:32 pm #286521
Working intermittently on a 1958 10hp Johnson. Watched several videos and read several forums. Saw that the mag cam should have “top” and an arrow imprinted on the top. Looking at the one I have there is no such imprints. Might it be installed upside down? Should I worry about this issue? I will be using a timing tool when I put the magneto back on, so maybe the arrow isn’t needed.
Thanks
edit: I pulled the cam off and it has no markings on either the top or the bottom and it will fit back on with either side facing up. It had the flatter section just before the “nose” of the cam that would let the point kick open quicker than it closes the point gap. Is this correct? Should the point open or close quicker?
Thx again.
April 5, 2024 at 4:26 pm #286525just follow this fellow’s method
http://www.youtube.com/watch?v=ga1Cjymj6ms&feature=youtu.be
if not tappered try one side or the other but set points per video
1958 Johnson QD-19 10 hp Outboard Motor Parts (marineengine.com)
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April 5, 2024 at 10:21 pm #286528I will tell tou another way that works on any magneto: First locate your two magnets on the flywheel, Use a straight edje to mark the outside of the flywheel. Next disconnert all wires from the points & connect a wire going thru the armature plate, about 24″ long. now mark the laminations on the plate. With flywheel just set on the shaft install a small lamp & battery to the wire. As you rotate the flywheel you will feel the firdt set of laminations, there are three to each coil. It will pass the 1 & 2 laminations, then 2 & 3 with the magnets, at that point your coil has recieved the max electro-magnetic energy & the points should open firing the coil. If these events don’t happen your points cam may be upside down. Try turning it over 7 retest. It’s failproof with any magneto.
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April 6, 2024 at 2:59 pm #286541Working intermittently on a 1958 10hp Johnson. Watched several videos and read several forums. Saw that the mag cam should have “top” and an arrow imprinted on the top. Looking at the one I have there is no such imprints. Might it be installed upside down? Should I worry about this issue? I will be using a timing tool when I put the magneto back on, so maybe the arrow isn’t needed.
Thanks
edit: I pulled the cam off and it has no markings on either the top or the bottom and it will fit back on with either side facing up. It had the flatter section just before the “nose” of the cam that would let the point kick open quicker than it closes the point gap. Is this correct? Should the point open or close quicker?
Thx again.
Usually one side of the cam has some sort of markings on it that should face upwards
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April 7, 2024 at 9:00 pm #286560One more question on the magneto for this ’58 10 horse… When I use the timing tool and adjust the points to open at the right time (begin opening as the tool aligns between the two marks on the mag plate) I see that the point gaps are quite different between the two when they get completely open. I can’t find my feeler gauge, so I’ll have to wait to get a new one in a few days, but I can see a difference. Shouldn’t both gaps be the same? Do I need to bend the part of the point that the wires are screwed onto a bit towards the rocker arm point on the one that opens wider to close the gap that’s too wide, or is there a better trick that I don’t know about? When I get the right tool (feeler gauge) I’ll do it again using the multimeter and the timing tool; not just eyeballing it.
Meanwhile, I’m moving over to change the impeller on a ’57 7.5 horse. It’ll be the first time I remove a powerhead for an impeller change. Wish me luck.
Thx
April 7, 2024 at 10:59 pm #286563Do I need to bend the part of the point that the wires are screwed onto …
NO! use the 2nd off-set screw … just loosen the main screw a bit holding down the points and use the pivoting one to adjust the gap.
but… in fact the gap size becomes more or less irrelevant if the points open up at the mid point of the two bars as in the video.
to set them with no tools just adjust the gap for .020 att he high point of the cam lobe.
7.5hp ph removal …careful with the top carbon seal !! very easy to break if you drop it !! see similar on a 5.5hp
try not to damage the base gasket . if you order a new one make certain the pattern matches yours !! they look the same but….
18-3001C – water pump kit for Johnson/Evinrude 5.5 hp and 7.5 hp 1956- – VintageOutboard.com
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April 7, 2024 at 11:11 pm #286567One more question on the magneto for this ’58 10 horse… When I use the timing tool and adjust the points to open at the right time (begin opening as the tool aligns between the two marks on the mag plate) I see that the point gaps are quite different between the two when they get completely open. I can’t find my feeler gauge, so I’ll have to wait to get a new one in a few days, but I can see a difference. Shouldn’t both gaps be the same? Do I need to bend the part of the point that the wires are screwed onto a bit towards the rocker arm point on the one that opens wider to close the gap that’s too wide, or is there a better trick that I don’t know about? When I get the right tool (feeler gauge) I’ll do it again using the multimeter and the timing tool; not just eyeballing it.
Meanwhile, I’m moving over to change the impeller on a ’57 7.5 horse. It’ll be the first time I remove a powerhead for an impeller change. Wish me luck.
Thx
As the flywheel magnets pass over the coil
lamination, the magnet field changes from
north to south. (or south to north depending
on the motor) This is the where you want
the points to open to get the best spark. The
factory gap setting will get you close if you
don’t have a timing tool. Point sets are far
from identical so the gap will be different
when they are set to open at the proper time.
Its when the points open the matters, not the
gap.
Tubs
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