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115 V4 2-Stroke 1978 no Spark at any cylinder

T

Trenchy99

New member
Hello,

So im told i have a 1978 model of above titled engine.
I sunk the boat at the beach a few weeks ago, didnt go fully under as we were close to shore. I got the boat home and dry and got the engine fired up and rinsed out the sea water, it ran a little rough, and i put it down to maybe sea water in the fuel.
a week later i tried to fire her up and was getting nothing, id have a few false fires where the starter cog drops out, but it would not fire.
I tested for spark and was getting nothing on all 4 plugs ( brand new plugs)
So i disconnected the the Kill wire (black/yellow) and to my surprise the motor fired right up.
It now seems that the earth and black/yellow wires, at the key switch, are shorted when the key is in the on/start position. if i disconnect the black/yellow wire from the ignition key switch, the motor will fire and run... then while running if i touch the black/yellow to the terminal on the key switch, the motor will stop.
I found this schematic which is identical to how my engine and remote are set up, but i cant find the actual "engine kill switch" that is on the drawing.

If i disconnect the big red plug, the short at the key switch wires goes.
If i disconnect the plugs going to the CDi units, the short at the key swich wires goes
Ive cleaned the ignition key switch out and tested the terminals and it works as it should

Im at a loss as to how to test the cdi units. im thinking that as the motor runs with the black/yellow disconnected that all the electronics are working fine..

Apart from splitting the harness and checking each wire for damage im at a loss...

Any tips or advice will be greatly recieved
WhatsApp Image 2023-06-12 at 16.40.32.jpeg
 
i cant find the kill switch, its not at the remote and i cant see one on the engine? what does it look like and where should it be?
 
the ignition key has a red surround that a landyard fits into and its rotated and locked in place, when the motor is running and the lanyard is pulled, the key is forced into the off position where it shorts out the black/yellow wire with the earth and subsequently stops the engine
 
i kinda figured that out, the kill lanyard is built into the key switch, it basically turns the key to the off position....
My problem is that the black/yellow wire is shorting to earth and i dont know if its the electronics or a damaged wire.
the engine runs if i disconnect the big red plug from the remote. and the short disappears in the remote wiring with the red plug disconnected.
 
like i said earlier;
When the big red plug is disconnected the remote wiring tests out ok.

When the big red plug is disconnected the motor will run on its own.

its only when the plug is connected the fault comes back....

i'll check the wiring but wanting to know if it could be anything else....
Im an electrician so im able to fault find, but outboards are a new thing for me and i dont want to spend money on CDi units if its not them causing the problem
 
faztbullet said:
I suspect keyswitch has a problem...
Click to expand...
Cheers for responding...
i have cleaned the keyswitch with contact cleaner and tested the terminals with a continuity tester and all the contacts work as they should when turning the key. Also the short im getting between the black/yellow wire and the earth wire isnt there when i disconnect the big red connector between the engine and remote. So im ruling out the keyswitch for now.
I'll be tracing wires next week when im home. ill report back what i find...
 
so i changed the ignition switch and that seemed to do the trick, untill i found out i had a broken spark plug... so changed all four plugs for new ones and she only fired up. The battery isnt that powerful, so was wondering what size CCA battery i should have for the 115HP motor..

any info greatly received
 
so after a lot of fiddling with batteries, kill switches and spark plugs etc, an old boy at the slipway suggested i clean the carbs... so i blew the air ways through on the carbs and the bloody engine runs lovely now... the idle is a little low and sometimes stalls when dropping into neutral... ive noticed that the timing is adjusted as the throttle is applied. the throttle needs to be almost 3 thirds forward before the engine really picks up. is this normal? is there any info somewhere on how to adjust the throttle and timing.... id rather not mess about without some knowlegde first...
Any advice will be greatly recieved...
 
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