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  Mercury 7.5Hp Outboard. No spark.

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Author Topic:   Mercury 7.5Hp Outboard. No spark.

pepperpot posted 04-30-2008 04:08 AM ET (US)
Soooo...
Guess I need some helping out here.
Yesterday I brought home my very first out board engine.
Not new but looking ok clean and neat.
I guess its app 15 years old but seems to have been running only a few hours.
But no spark from none of the two spark plugs.
Tried out:
Two new spark plugs.
Cleaning the spark plug wires at both ends.
Widened the upper end of spark plug wires in order to get better connection.
To eliminate the possibility of a short cut in a switch I removed the black wire from the stopswitch from engine.
Still no spark.
What could possibly be wrong here ?
Thanks
PP

pepperpot posted 04-30-2008 04:39 AM ET (US)
Hey again.
I just uploaded 3 pictures of the engine to
http://gearhiker.eu/baadmotor.htm
PP
jimh posted 04-30-2008 09:29 AM ET (US)
The most common cause of no spark is the absence of the safety lanyard in the safety lanyard switch. Without it in place, there will be no spark.
pepperpot posted 05-01-2008 08:09 AM ET (US)
Thanks J
Since the two wires for the safety lanyard switch are the tvo orange wires from the box 2 in my photos
( http://gearhiker.eu/baadmotor.htm )
it would probably be ok to cross circuit those with a piece of wire directly at the box ?
(For the test only of course !!)
Or would that ruin anything hidden in the box or elsewhere ?
PP
jimh posted 05-01-2008 10:48 AM ET (US)
On my motor, the safety circuit is CLOSED to suppress ignition. I do not know how it works on your motor. If may work in the opposite sense.
pepperpot posted 05-01-2008 10:30 PM ET (US)
Thanks Jimh
Yesterday I found an old local guy who practically breathes through these old Mercury engines.
He has promissed to help me out here. He has several scrap engines for spare parts and says that my engine will be up and running in a day ... Let´s se that ...
I will for sure be back and check this site from time to time.
Many thanks here from Denmark
PP

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Author	Topic: Mercury 7.5Hp Outboard. No spark.
pepperpot	posted 04-30-2008 04:08 AM ET (US) Soooo... Guess I need some helping out here. Yesterday I brought home my very first out board engine. Not new but looking ok clean and neat. I guess its app 15 years old but seems to have been running only a few hours. But no spark from none of the two spark plugs. Tried out: Two new spark plugs. Cleaning the spark plug wires at both ends. Widened the upper end of spark plug wires in order to get better connection. To eliminate the possibility of a short cut in a switch I removed the black wire from the stopswitch from engine. Still no spark. What could possibly be wrong here ? Thanks PP
pepperpot	posted 04-30-2008 04:39 AM ET (US) Hey again. I just uploaded 3 pictures of the engine to http://gearhiker.eu/baadmotor.htm PP
jimh	posted 04-30-2008 09:29 AM ET (US) The most common cause of no spark is the absence of the safety lanyard in the safety lanyard switch. Without it in place, there will be no spark.
pepperpot	posted 05-01-2008 08:09 AM ET (US) Thanks J Since the two wires for the safety lanyard switch are the tvo orange wires from the box 2 in my photos ( http://gearhiker.eu/baadmotor.htm ) it would probably be ok to cross circuit those with a piece of wire directly at the box ? (For the test only of course !!) Or would that ruin anything hidden in the box or elsewhere ? PP
jimh	posted 05-01-2008 10:48 AM ET (US) On my motor, the safety circuit is CLOSED to suppress ignition. I do not know how it works on your motor. If may work in the opposite sense.
pepperpot	posted 05-01-2008 10:30 PM ET (US) Thanks Jimh Yesterday I found an old local guy who practically breathes through these old Mercury engines. He has promissed to help me out here. He has several scrap engines for spare parts and says that my engine will be up and running in a day ... Let´s se that ... I will for sure be back and check this site from time to time. Many thanks here from Denmark PP