1970 merc 800 only starts with key held on

[macstang99]

ive got a 1970 mercury 800. While woking on yet another problem with the throttle control, i started the motor up two or three times and everything worked perfect. the battery died while doing this, so i charged it over night, hooked it back up, turned the key, it turned on, but as soon as i let go of the key to return to on position, it shut off. thought maybe i had a bad primer bulb so i went and put a new one on but it still does the same thing. it will only run off the starter. bad fuel pump possibly? please help!!!

mac

 

[Texasmark]

Re: 1970 merc 800 only starts with key held on

I'm going to go for a bad ignition switch and say that it is just circumstantial that it occurred when it did. Ignition power is supposed to be (has to be) supplied in Run and Start. Apparently the only time you are getting it is in Start. Nothing else makes sense. :%

Mark

 

[ricksrster]

Re: 1970 merc 800 only starts with key held on

the ignition switch in the on position supplies + 12 to things that require power from the key on position. The off position of the ignition switch connects the Engine kill wire to ground. Your on position might be shorting out with the engine kill.

 

[macstang99]

Re: 1970 merc 800 only starts with key held on

the ignition switch in the on position supplies + 12 to things that require power from the key on position. The off position of the ignition switch connects the Engine kill wire to ground. Your on position might be shorting out with the engine kill.

 

[macstang99]

Re: 1970 merc 800 only starts with key held on

ya, that sounds like a good possibility. could it also just be a bad ground?

 

[ricksrster]

Re: 1970 merc 800 only starts with key held on

Yes it could! Check all the wire connections for loosenees and corrosion.

 

[rickdb1boat]

Re: 1970 merc 800 only starts with key held on

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[macstang99]

Re: 1970 merc 800 only starts with key held on

thanks for the info. it was very helpful. ended up being a bad trigger, starts up great now! thanks again