1984 Johnson V4 140hp Outboard dies durin planing.

[We Ride...]

1984 Johnson V4 140hp Outboard
It was failing to advance the timing so I could plane. So I took some penetrating oil, and spraying it up into the collar under the flywheel, got it all loosened up. Now it planes effortlessly.
However, twice I have been towed in since.

The boat operates at start up and 200 rpm increments up to planing. It planes for a minute or two, but then shuts down.
By that I mean, it doesn't cough or sputter or surge. It simply dies.
Can't start it again.
After a nights rest or after cooling, it starts.
Fuel is ample.

In my experience, that means a circuit is breaking down under heat?!?
Plugs replaced.

Any ideas?

Thanks


Kyle

 

[racerone]

How long have you owned the motor ?-------Have you tested the overheat horn ?-------Is the motor running with VRO in service or are you mixing at 50:1 ?

 

[We Ride...]

owned it 6 years. Running 50:1

 

[boobie]

When it dies on you and won't start, check your spark. It should jump a 7/16" open air gap on a tester.

 

[1NewBoatGuy]

I would suspect an ignition problem if you are certain of good fuel supply to all carbs. It really sounds like a flooding issue. Running rich or fouled spark plugs.I would pull the plugs and check there condition. Check for good spark from wires then check that all carbs are operating balanced. When you have multiple carbs this get's tricky if you have been doing work with them. But easy to check.
Pull off the covers off and check that the butterflies are seated with the throttle all the way back. Now move the throttle to Wide open and check that the butterflies are parallel with each other.
If your carbs are set properly, you have an ignition problem or improperly jetted carbs. If the carbs have not been rebuilt I would suspect ignition problems.
Check the gasket colors as well. Orange rubber gaskets would indicate a more recent rebuild, cork gaskets indicate original setup.

 

[emdsapmgr]

Weak ignition components tend to fail once the engine heats up to normal operating temps. May fun fine when cold, then crap out when warmed up. Next time the engine quits, put a timing light on each plugwire and check for spark when cranking. The flashes from the gun will show intermittents, weak firing, no fires, etc. If you have a no spark condition, it's unlikely all 4 coils went bad all at once, and that both power packs failed- so you'll need to verify the other ignition components. Stator and timer base.

 

[V153]

Timer bases on these rarely go bad. I'd lean toward the stator overheating. The aftermarket ones run cooler because they're not encased in epoxy like OEM.

(CDI pictured.)

 

[daselbee]

Piston seizing in cylinder shuts down engine. do compression test. if it is a seizing piston, when you try to restart, it will sound like a dead battery. If this is what it is, the damage is already done. You have a lean cylinder.

 

[emdsapmgr]

Daselbee offers up another slant on your problem that you'll need to look for. An overheat lockup. When a piston gets to hot, it expands and will actually lock/sieze up inside the cyl. The engine won't crank again till it's cooled down. Usually when this happens, other bad internal things have already occurred. You can clarify this by re-stating your problem: "it won't restart." Can you be more specific? Does it crank over-but does not restart, or does the starter not even turn over the flywheel? Big difference in a solution. The first issue could be ignition, the latter issue is the problem he addresses in his comment. Been there, done that.