1958 Johnson 10hp Seahorse Outboard (QD-19) running on one cylinder

[MikeW25]

(i.e. engine is running on one cylinder) So I’m looking for help on my grandpas 1958 Johnson 10hp outboard. Couple weeks ago I pulled the engine out of the garage got it in a barrel and got it running after 15+ years of sitting. That was all I did to it, 24:1 gas mix no carb clean or absolutely anything done to the inside. This week we went up to the lake and I put it on our little 12 ft aluminum. When I got it in the water it idled okay at the most throttle I could give it in neutral, when I tried to give it less and put into reverse it almost died until I revved it up and pulled out a bit. When I shifted into forward and slowly went up to full throttle, the boat felt very sluggish and the motor felt extremely underpowered, not even able to plane out. Went back to the dock and couldn’t get the motor to idle anymore so I checked spark, good spark in the top and nothing in the bottom, during this time I also replaced the plugs with champion J6C plugs and it runs a little better at full speed (about 6.5 mph). I’m thinking it is an ignition problem but maybe someone knows a little more than I do (I’m a young tinkerer) any help would be appreciated!

 

[hardwater fisherman]

If ignition coils are original then they will be cracked and need replacing..

 

[racerone]

Remove recoil starter.-----Remove inspection plate to look at coils.------Clean breaker points and test spark.

 

[Crosbyman]

what to expect if never changed... and for father's day buy grandpa a new impeller and change the gear oil for him. easy job.

btw... splurge on a set of condensers and points and maybe you grand children will go fishing with it.

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Troubleshooting outboard

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[MikeW25]

If ignition coils are original then they will be cracked and need

Is that a difficult job?

 

[hardwater fisherman]

Is that a difficult job?

Is that a difficult job?

Depends on your ability. Do what racerone posted in post #3.

 

[hardwater fisherman]

The inspection plate looks like this. Rotating the flywheel clockwise will allow you to see the coils ect.

 

[racerone]

I will be teaching the 12 year old grandson to maintain this magneto on a 59 model 5.5 HP.----I was repairing these magnetos at a shop when I was 18 years old.----So in my opinion it is not difficult.-----Visit ----leroysramblings----- to learn everything about these simple motors !!

 

[Crosbyman]

Is that a difficult job?

yes no...

it involves lifting the flywheeel with a small puller to gain access to the coils for removal (3 bolts each)

then it requires unboltingt the mag plate to disconnect the plug wires from under the coils ......and you really should buy 4 feet of 7mm solid core wire to the replace the old plug wires.

the new wires screw in the coils.... then the coils sit in the FW coil cavities. the end boot s for the plugs can be reinstalled.

utubes are available to show you how... including adjusting timing wit 100 % accuracy

it is a learning process ,not hard but you do need some tools patience and etch. ability.

then it becomes a lifelong hobby visit the AOMCI site where old motors are the reason for their addiction.... then neighbors will come see you

Forum: Ask A Member – Antique Outboard Motor Club,Inc

aomci.org

 

[MikeW25]

it involves lifting the flywheeel with a small puller to gain access to the coils for removal (3 bolts each)

then it requires unboltingt the mag plate to disconnect the plug wires from under the coils ......and you really should buy 4 feet of 7mm solid core wire to the replace the old plug wires.

the new wires screw in the coils.... then the coils sit in the FW coil cavities. the end boot s for the plugs can be reinstalled.

utubes are available to show you how... including adjusting timing wit 100 % accuracy

it is a learning process ,not hard but you do need some tools patience and etch. ability.

then it becomes a lifelong hobby visit the AOMCI site where old motors are the reason for their addiction.... then neighbors will come see you

Forum: Ask A Member – Antique Outboard Motor Club,Inc

aomci.org

Thank you all so much, will be using this information when I get back to give it the rebirth it deserves. After running the boat for a little while on one cylinder it decided that it finally wants to go on two! Still won’t get it to idle properly as the bottom cylinder doesn’t fire but in the higher rpm’s she runs on both great! Definitely needs a new impeller and gear oil.

 

[Crosbyman]

sometimes plug wires are frayed and ground out or go open depending on the rotation of the magneto ending up causing faulty operation.

at a given speed setting the wires bend and may go open

 

[racerone]

Do you have spark on both leads that will jump a gap of 1/4" or more on a test device ?----Sparkplugs are not used for testing maximum spark output !----For an experiment remove bottom sparkplug.-----Close the gap on that plug to 0.020" then test run.------You may have a bad coil that is shorting out to the magneto plate.----Remove flywheel and inspect coils.

 

[Crosbyman]

"the new wires screw in the coils.... then the coils sit in the FW coil cavities. the end boot s for the plugs can be reinstalled."


ooops... make that magneto plate coil cavities !