late 1970s mercury 50hp thunderbolt wont stop

richrally

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Joined
May 24, 2009
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4
Hi I have just been given a merc 500 thunderbolt, I have got it started to my supprise, but I dont know how to stop it, It has one coil on it and a distributor.The only way it stops is to cut the fuel off. Does anyone have any idea how its meant to stop thanks.
 
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AMD Rules

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Sep 23, 2004
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Re: late 1960s mercury 50hp thunderbolt wont stop

Re: late 1960s mercury 50hp thunderbolt wont stop

If you'll post your serial number, I can determine the model year. From there, we can then discuss ignition circuit logic specific to your motor.
 

richrally

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May 24, 2009
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Re: late 1960s mercury 50hp thunderbolt wont stop

Re: late 1960s mercury 50hp thunderbolt wont stop

Hi Im not sure where the nimber is, I have looked, Do you know where it would be?
 

AMD Rules

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Re: late 1960s mercury 50hp thunderbolt wont stop

Re: late 1960s mercury 50hp thunderbolt wont stop

Should be on the round steering tube just above the transom clamps, front & center... or, on some models it will be on the transom brackets left or right side down near where the tilt pin is located, on a nameplate.

Last resort, if you look on the bock itself you may see a round silver disk (welch plug) that often has the serial number on it.

Should be a 7 digit number, if its late 60's era.
 

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richrally

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May 24, 2009
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Re: late 1960s mercury 50hp thunderbolt wont stop

Re: late 1960s mercury 50hp thunderbolt wont stop

I cant seem to find anything on it. Ive been looking at pictures on internet and ive seen a couple that look the same model and they are 1970's. looking at one of the pictures,which is identical and thats a 1978 model
 

richrally

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May 24, 2009
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Re: late 1970s mercury 50hp thunderbolt wont stop

is there anyway I can cut the spark off by installing a switch? Is it possible I could splice the earth wire from the coil to cut the spark?
 

rtpassini

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Nov 27, 2008
Messages
508
Re: late 1970s mercury 50hp thunderbolt wont stop

look around on your block. the serial number will be stamped on there.
 
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