1974 85 hp mercury problems runs but not

[DIE FOR FUN]

need help lots of help with this one. 1974 85 hp mercury . installed new distributor cause trigger was bad.new fuel pump. new plugs.rebuilt carbs. new ignition switch. has got good compesion. good spark. BUT.... when i start it . it will fire up as long as the ignitoin switch is turning the starter motor over. let go of switch to run position an it dies. tried removing power 2 starter an it dies.tried giving power 2 white wire 4 ignition circut still dies took an old harness cut control box off . used red power lead. white lead 2 ignition and yellow 4 starter. starts up till u disconect yellow 4 starter can some one show me i am dumb and missing the obvious thanks.

 

[sc00ter78]

Re: 1974 85 hp mercury problems runs but not

I will look more tomorrow at my book and get back to you. Have you tried pulll starting it? The key has to be on the on position to pull start.

Sounds like a faulty kill switch or switch box. An electrical issue of that type. Somehitng is iterupting the power to keep it running.

 

[Chris1956]

Re: 1974 85 hp mercury problems runs but not

That dissy ign motor needs to have power to the red wire on the switchbox at all times. The white wire next to the red wire gets power from the ign switch, when it is in the on position. I would check these two connections and see what is happening.

 

[Moody Blue]

Re: 1974 85 hp mercury problems runs but not

Sounds as though the ignition switch is wired incorrectly.

Can you identify each of the terminals on the switch and what color wire is attached to it?

 

[DIE FOR FUN]

Re: 1974 85 hp mercury problems runs but not

2 merc dealers later and and i still feel dumb lol. so far ive changed the coil , solinoid, switch, harness, key switch, distributor, cleaned any and all connections. gave the engine a new ground from the battery.used meter 2 check for shorts open wires anything 2 no avail. still engine dies when ever the starter power is shut off. used an old harness with control box cut off does the same. wiggle test on wireing while running. what could the starter motor have anything 2 do with the engine running ?

 

[Moody Blue]

Re: 1974 85 hp mercury problems runs but not

See my post above. Likely you wired the ignition switch incorrectly. The original switch performed a number of different "operations" in the different positions.

Did you record the terminal letter and wire color information when you replaced the ignition switch?

 

[DIE FOR FUN]

Re: 1974 85 hp mercury problems runs but not

LOL read my post above used another harness with the control box cut off. no start switch no nothing just a bare set of wires in my hand. touch the red wire to the yellow to engage start solinoid white wire to red to give ignition power engine starts and runs till u remove the yellow or the power wire on side of starter and the engine dies.

 

[DIE FOR FUN]

Re: 1974 85 hp mercury problems runs but not

well im on the water now an flyin faster than i should lol . the new distributor was a bad one all along. thanx 4 the replys.

 

[Moody Blue]

Re: 1974 85 hp mercury problems runs but not

Thats good news. Thanks for posting back with your results, it helps others.

A classic symptom of a bad trigger is that the motor will only run with the key in the start position. I overlooked the obvious when you stated you installed a new distributor. Duh !!!!