Setting Points & Timing 1976 Johnson 15 hp Model 15 R 76 A

kcrow

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Oct 12, 2015
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I am setting points on the above motor for the top cylinder .The cylinder is at "TDC" .On the top of the cam i have the stamping"s "SET/TOP". I have set the points using the "SET" mark to 0.20 per the plate. When i drop the flywheel back down onto the the keyed shaft the timing mark for the top cylinder is no where within the range on the stamping or casting line of the flywheel in relation to the plate . Am i missing something? Or do i have another problem?.
 

racerone

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There are 2 timing marks on the bottom of the flywheel.---There are 2 vertical timing marks on the magneto plate.-----Have you found these marks ?
 

OptsyEagle

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The timing marks and the set point are not supposed to be aligned. The spark fires when the points JUST open, not when they reach a gap of 0.020". The engineers at OMC designed this so that if you set the points at 0.020" when the rub bar is at the SET point, then the point will JUST open when the flywheel is at the timing marks (and the piston is close to TDC). I hope that makes sense.

The other way to set the points is to hook up a multimeter to the point (need to disconnect the driver coil and the condenser). Set the multimeter on continuity. Now turn the cam very, very slowly and when the circuit JUST goes open as read by the multimeter, stop turning. Now grab the flywheel and align it to where the flywheel key is. The timing marks should be aligned at that point. Now turn the cam a little more to the SET mark and measure the point gap. You will find that the gap will equal 0.020". The engineers at OMC did know what they were doing.
 

flyingscott

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Just set the points where the set mark on the cam is to .020 . You should be replacing those points and condensers with brp parts that motor is really hard on points and condensers. Put the flywheel on and see if it runs.
 

kcrow

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Racerone yes i have found those machined marks on the flywheel and the mag plate. I guess my real question should have been once the points have been set at 0.20 and the flywheel is dropped on the key way. should the timing mark for the top cylinder be within the mark of the mag plate in relation to the points being opened ? But it sounds like OptsyEagle pointed out "THE SPARK FLYS WHEN THE POINTS JUST OPEN.So i think i"m good and will see what happens. So Thank you "ALL" for taking the time for the information and answer my questions...........
 

HighTrim

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What Optsy said. You are trying to set them using 2 different methods. Setting them at 020 when the rubbing block is aligned with the SET will get you close enough if all you have is feeler gauges. If you want them exact, and exactly 180 degrees apart, set them with a timing fixture or with the timing marks as described. This will get you a better idle, and better starting properties.

After setting, clean well by running paper dipped in acetone through them and then blow dry with compressed air. You want them spotless.
 

OptsyEagle

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Yes. The timing fixture method or my multimeter method is a little more accurate, but every time I beat it to death and used the more accurate method and then measure the point gap after. It always read extremely close to 0.020". So I don't bother with the elaborate methods anymore. I figure soon enough a little gap will be lost to rub bar wear anyways so lets not get to technical.

I wouldn't say those motors are hard on points, but if you don't use the motor for a couple of seasons, almost for sure point corrosion will kill your spark and they will need to be filed and cleaned again.
 

HighTrim

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Check idle characteristics though after. The timing fixture gets the fire exactly 180 degrees apart. You cannot do that by feel, unless you are Spiderman! lol
 

flyingscott

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you don't need the timing fixture most dealerships will set the points with the set mark on the cam. If you want to be accurate use the go-no go method. Take a .019 feeler gauge it should go through the open points without touching. now take a .021 gauge and it should go through with some friction. I have changed a lot of points and never had a complaint about how they run different. I would be curious how many people actually own the timing fixture or if it is even available.
 
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racerone

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The timing fixture is nothing but a " dummy flywheel "------With some care you can use the flywheel timing marks along with the 2 marks on the magplate.
 

HighTrim

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Nope, don't need a timing fixture, but definitely much better with one, that's all. I went many years using feeler gauges with great success. But once I bought F__Rs fixture (find him on this forum), I never went back. Im assuming you do not have one? I can promise you that if you invest in one, you will not go without it. As Racerone said, you don't even need the fixture on many motors that have the marks embossed on them, just much easier with it as you don't have to take the flywheel on or off, or drill a hole in the may plate for the test leads. To add to that, getting a buzz box, or a meter that can read under an ohm, makes things easier still as you do not need to remove the leads.

Flying Scott, Im not sure what you mean by that motor being hard on points and condensors? What am I missing?

For my own motors, and I am talking 60s vintage and older, I like the original points. For years, I thought replacing was necessary, but have quickly learned that they don't make em like they used to. The original points in them are of much better quality than what you will buy today, even OEM. Unless the rubbing blocks are worn beyond use, but that is pretty rare.

When I restore a motor for a customer, I replace the points, as they feel like I should, even if the originals are better than new. We live in a wasteful society. So, I reluctantly replace them, but keep them for myself and my personal motors.

I test all condensors, I don't just replace them because. I find the originals from 50s or 60s are about 50/50 if they have the red paper top. So, if they have the original red paper tops, and you don't have the ability to properly test them, I can see replacing them.

If they have been updated to the black rubber caps, they are almost always good, but there are still the bad ones out there.
 

flyingscott

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The 1974-76 9.9/15 hp ignition systems are specific to that model. It is not the same as the older style with the coils under the flywheel which was a great ignition. The coils are external and it has a single spark pick up under the flywheel with the points kind of a hybrid system. It's known for being troublesome but most of the trouble I have found with them is the aftermarket points and condensers don't hold up to it. I also find some people just convert them to the cdi ignition. It's not a great ignition system but if you can get them dialed in and they still have the original head on them some of the fastest 15s you can find.
 

dln0302

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Oct 12, 2015
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I am trying to get a 1997 9.9 hp 4 stroke Yamaha going for a 92 yr old man. He was a bomber pilot in WWII. I want him to enjoy his pontoon one more time. It ran fine 10 yrs ago but now has no spark. I know the plugs are good. I checked them on a lawnmower. Everything looks like new so no mice have been eating wires. Working backwards I would not think that 2 coils would both go bad. I'm not a boat person. What is a safety lanyard? Would that apply here? Please help.
 

flyingscott

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Dln302 you need to post this in a yamaha forum starting a new thread will get you better answers. The lanyard is a safety switch on a red cord if it is pulled it will kill the ignition. If it is on a pontoon boat the lanyard switch should be on the control unit.
 

tanuki

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Just as a side note with regard to drilling a hole in the plate for the test leads?. On my 1975 rude 9.9, instead of drilling a hole I used a guitar string (like an electrical snake) to run a thin wire up thru the wiring harness to use as a test lead. The test lead is permanently in the harness and when I am done static timing with a meter. one end is tucked under one of the coils and the other end is capped externally. I use the flywheel as my ?fixture?. May take a little longer than using feeler gauges but my 40 year old motor really idles and runs fine this way. Just my 2 cents,,,
 
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