1974 Johnson HP6 - what have I done?

[Scubaseas]

When I was using my 1972 the part #24 would break so you couldn't shift it but you could still move the throttle. I don't think it's an issue for you but maybe check it.

[jimbunyard]

Was going to suggest wear/corrosion allowing the linkage to overextend (or some permutation of that), til I watched the latest video. Damn that thing looks in good shape for 46 years old

Anyway, still think it might have to do with overextension, my first try would be to reverse what caused it in the first place; spray some oil on all the linkage pivot points you can see, hold the flywheel from turning and try and throttle it up. If you're worried about using the twist throttle, find which way the advance plate is supposed to move, and figure out a way to move it in the correct direction manually.

If it pops loose, I'd still want to remove the flywheel to make sure something's not going on under there that needs to be addressed, it's pretty simple, all you need is a steering wheel puller, 3 bolts to screw into the f/w and an impact driver and socket to remove the flywheel nut.

[Scubaseas]

The plate advances the timing. Flywheel turns clockwise, plate goes anti clockwise as the throttle opens. Do not force the throttle too hard as most of the parts are no longer available. Most of the parts of the plate and mechanism are pot metal/cast aluminum so careful if beating or prying on them.

[Nicholson58]

I suggest you remove the plugs and observe the Proper motion of the pistons while you rotate the flywheel. If this is all OK then internal issues of piston, pin, crank, connecting rod are eliminated.

These oldies are really easy to work on and easy to trouble shoot.

[keylime]

Had a closer look and notice that one of the cables is pinched under the throttle plate. Can anyone tell me if it should be like that?


https://youtu.be/Oo0s09a707M


I'm gonna try with some liberal use of CRC556/WD40 and see if it loosens up.

[Scubaseas]

Those are the spark plug cables or secondary ignition wires. They are supposed to be held up by clamp #29. They should not lay on top of the linkage. Try gently pulling the wires towards the plug and see if that frees up the plate. They really shouldn't move though. The clamp #29 is supposed to hold the wires snug up to the plate

[jimbunyard]

The wires, shown in your video are as they should be, as advised by Ss above, the clamp 29 above retains them to avoid abrasion damage.

I really think you should just try and reverse the force (while holding the flywheel) that caused it to jam, after spraying liberally with whatever 'miracle' juice you have. I prefer sprays that have oil in them; their effect lasts longer.

Chances are very good that it will just pop free, the key is to know how much force to use; my description would be firm to very firm, with a combination of slow, steady application and rapid 'jiggling' from zero to whatever-you-feel should be maximum pressure.

If that doesn't do it, time to pull the f/w...