73 johnson 20hp ignition coil question?

[noppy]

hi, im restoring in a word a 73 johnson im already replaced the plugs, cleaned the carb, pistons are moving freely, selects gears but ....
only getting a spark in one plug so today took the top off to check the points to find the ignition coil that had no spark with cracks all in the casing.... i have two questions
1) how do you check if they work?

2) i have found what i believe to be a replacement on ebay brand new is it as simple as that do they just swap or are the specific?
http://cgi.ebay.co.uk/JOHNSON-EVINR...VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

thanks Gav

 

[Joe Reeves]

Re: 73 johnson 20hp ignition coil question?

If the coil is cracked, replace it. If unsure, switch the coils. If the problem follows the coil, then you're sure the coil is faulty.

(Magneto Coil Alignment)
(J. Reeves)

To align the coils properly, have the metal vertical portion of the coil yokes aligned with the inside edge of the bevel that exists on the top portion of the aluminum seat upon which the coils sit. This creates the proper distance between the coils and the flywheel magnets. Faulty alignment creats friction and the yokes of the coils heat up, turn blue and expand.

(Point Setting Of Magneto Models)
(J. Reeves)

Set the points as follows. Have the flywheel key aligned with the fiber rubber portion of the ignition points. Adjust the gap so that a .020 gauge will pass thru but a .022 will not. Should there be any question of the points being dirty (touching the contact with your finger would cause them to be dirty), clean them with a small brush and acetone or lacquer thinner.

NOTE: Should the operating cam have a small portion on it with the word "SET" imprinted, align this portion with the fiber rubbing portion instead of the flywheel key.

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

cheers for the quick reply i shall do as you said and report back im 99% sure its faulty an will need replacing but theres no harm in testing.

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

i have another question about my outboard, where is the zinc anode ? i cant find it ? is it inside the leg?

 

[Joe Reeves]

Re: 73 johnson 20hp ignition coil question?

If there'a a zink anode, it was an added item. It would be attached to the outside of the lower unit, usually on the cavitation plate. If you don't see it, it isn't there.

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

switched the coils round and its dud iv ordered a new one from the states so could be a while yet for it to arrive. thought this probably a stupid question but am i assuming rightly that it would be a good idea to change the oil in the lower leg ?

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

YAY my new coil arrived today i shall fit it after food touch wood it will start with a new coil

 

[Joe Reeves]

Re: 73 johnson 20hp ignition coil question?

Always a good idea to check the lower unit lube.... BUT.... do not remove that philips screw that you'll see there. That's a long pivot pin for the internal shift lever.

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

well still no spark so il replace the HT lead if that doesnt work it'll have to be a new condenser

 

[Joe Reeves]

Re: 73 johnson 20hp ignition coil question?

Always a good idea to replace points and condensers when restoring, repairing, tuning a engine.

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

Yay it started, but wont idle just cuts out must be something to do with fuel, it will run for a few seconds at very high revs. any suggestions as to my next move?


gav

 

[iwombat]

Re: 73 johnson 20hp ignition coil question?

First, don't run it at high revs unless it's in the lake and in gear. Thermal runaway is a bad thing.

Second, have you tried choking it to keep it running? What about pumping the bulb?

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

havnt tried pumping the bulb but tried choking

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

the engine is now running pretty much properly just a few fine touches left, engages gears aswell,

i have one concern there is scummy oil (i think) coming from the side of the engine half way up where there is a little plate, should i be concerned

 

[Joe Reeves]

Re: 73 johnson 20hp ignition coil question?

Supposed to be a gasket in back of that plate but no need for concern.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note 1: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

 

[noppy]

Re: 73 johnson 20hp ignition coil question?

cheers thats great info i shall do it tomo