1981 Johnson 70 , storage dramas

[andrew j cox]

Im working on my current project, the 70 on him hasn’t run in years, guesstimate 5-10 years, had a brief look at it, starter was seized, bit of wd40 and a spanner and it freed up, engine winds over, I hooked the ears up to it, put fuel too it, and great big bugger all not even a fart,
I left it at that, now I need to get it going, I guess I should compression test him first, if that’s ok, need to find out why there no spark, these are a magneto system? Could be the CD units cactus, what’s under the Flywheel that might cause probs?
no doubt the carbs will need a tickle up and a new fuel pump, probly the impeller is shot too.
Im new to OMCs people say these motors are God’s gift to boaties,
What stops them? What to look out for with them?

 

[Joe Reeves]

Sitting for that length of time... the carburetors are fouled... clean and rebuild them.

The engine, keeping it simple, has a magneto capacitance discharge ignition system..

Check the compression with all s/plugs removed.

Plugs still removed... check the spark which should jump a 7/16" air gap with a strong blue lightning like flame... a real SNAP!... Does it. Note that the 7/16" air gap is important!

Let us know what the psi compression is on all cylinders.... and the results of the spark test.

 

[andrew j cox]

Compression come it at 100 for top 95 for middle 90 for bottom, i guess its got stuck rings what will free it up? Wait till its running get it hot give it a good long run and try again? Or fill it with a tranny oil and acetone mix and let it soak.
What it did was clean a spot on the jacket cover to bare alloy, I then earthed each plug one at a time while the wife turned the key I got a crack, my eye sight is not much chop I couldnt see a flash but I got 3 cracks, I do got a Toledo spark tester when I did my mates Suzy I had to unscrew the tip to go into the Suzy leads I lost the lil end screw all my spare plugs are fixed tips, after I have stripped the starter and solved its issue Ill dump the carbys off and clean them out ill try get some action from it, if it starts, then ill do the waterpump up and service the gearbox, all should be good fingers crossed