OMC Cobra failure to start .

ab59

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I have got my boat to the point where I need to start and run the engine as well as test the shifting adjustments that I have made after a new transom cable was installed.
I set the Tsm cable up with the OMC jig but after assembly would not shift into reverse . I thought I had solved that problem by adjusting the controller cable to fit the bracket . It does shift into forward and reverse fairly smoothly and I thought the problem was solved.
Now I have an engine that will not start and after repeated inspections I believe the wiring is connected correctly and it started and ran with no problems Before I replaced the Tsm cable.
I am now looking at the interrupter switches on the bracket as the possible cause. Everything looks ok to me but I'm kinda in the dark here on what is and is not the correct position for the switches . A little help for those who know would be great.
I will post a couple of pics of the bracket , the shift lever is in Neutral Position .

i bought a new cybershot 21.1 mp camera as the old 7.1 mp CS quit working and I can't seem to upload the pics here for some reason . File size says 124 kb but iboats says that they are over 2 mb ? I dunno​​​




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Bondo

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Ayuh,...... What motor,..?? What vintage,..??
 

Lou C

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Does it crank over and not fire?
Or does not even crank?
You might check the large cannon connector which is right on that shift cable bracket, I put a hose clamp on mine to keep it from getting loose. If you think it has something to do with the ESA system you could always uplug it as a test. On the OMC it does not short the ignition like on the Merc, it just lowers the idle. So it should not stop it from starting even if its engaged when it should not be.
 

ab59

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Hey Lou good to hear from you. The engine turns over fine and tries to start but when I let off the key it just dies out. Never had a problem starting before I pulled it out the second time. Funny thing is when I pour a little gas in the carb to prime it a little it does not try to start at all until it has more or less sucked all the gas through the engine.
I remember that mine had a hose clamp on the big plug as well but I did not put it back on so I will put it back tomorrow if the never ending storms permit it. I will also disconnect the ESA and see if that helps.
thanks for your reply Lou I appreciate it .
 

Lou C

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You’re welcome! Have you checked for spark? That model originally had a points distributor; if you have no spark you might need to put in a new set of points and condenser. Sometimes the condenser just goes bad.
if you have spark the comment about it not trying to start till all the gas is sucked thru the engine could suggest that either the choke pull off is not working or the carb float is stuck flooding the engine. Is it a 4bbl Quadrajet?
 
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Bondo

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The engine turns over fine and tries to start but when I let off the key it just dies out.

Ayuh,...... The Ignition circuit is powered 2 ways, 'n it sounds like yer missin' the 1st connection, at the motor,....

When crankin' on the starter, the ignition is fed battery voltage from the outside tiny terminal on the starter's solenoid,.....

When ya let go of the key, the ignition circuit is powered only from the key switch,......
 

Lou C

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I thought of what Bondo said and pulled out my OMC wiring diagram. The positive terminal on the ignition coil is fed by two wires: a purple black wire that goes to the small outer terminal on the starter and a purple red wire that goes to the excite (E) terminal on the alternator. Try checking voltage between the + and - terminals on the coil when you are cranking it & report back...
first thing I always do in a case like this is make up a ground wire with large alligator clips. Then disconnect one plug wire and plug a good spare spark plug into it. Use the ground wire to ground the body of the plug to a good ground on the engine. Then have someone crank it (or use a remote starter switch and watch for spark beteeen the electrodes. This tells you if the primary and secondary ignition systems are working,
 

ab59

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Thanks for your replies guys- We are in the middle of another week long storm with rain and wind blowing about 30 mph so will have to wait until the weather is a little more cooperative to get much done.
I keep thinking about the problems I had with the starter solenoid a couple of weeks ago and now after reading your posts about the ignition wire at the starter I am wondering if that is not where the problem may lye .
As suggested , I will have a good look and test the wires to see if this is the case.
Will post the results when I can get back out there.
thanks again----
 

Bondo

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I am wondering if that is not where the problem may lye .

Ayuh,..... I'd start with a test light, 'n see if there's voltage at the coil's (+) tiny terminal, with the key "On", 1st,.....

The fact that the motor tries to start, while crackin' on the starter, says that circuit Is, in fact, Workin',.....
 

ab59

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Been storming here for days on end . 45 mph winds and rain yesterday and the day before 60 mph winds and rain today . Just don't have the starch left in my shorts to get out there and try to work in that kind of weather . Soon though , I hope.
 

ab59

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OK guys , back in the saddle---
I climbed into the boat and tested the + side of the coil with the key in the ON position and got NO reading. I then checked the back of the ignition switch and found that there was current there in the on position with one blade being hot continually ie key " off " position.
From there I traced wires and then pulled the MAIN harness plug and found it full of some kind of protective jelly that may be preventing a good connection to the coil wire. Is this jelly common to all these main harness plugs to prevent corrosion ???
I have a can of electric connection cleaner that I could use to clean some of the jelly out but not knowing for sure about the reason for it being there I am hesitant to use the cleaner.
What would you guys think about this ?
 

Lou C

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On your igniton switch there should be 3 terminals: B for battery, has battery volts when battery switch is on (red wire)
I for igniton, has battery volts when you turn the key to the 1st notch (ignition on) (purple wire)
S for start, gets battery volts only when you turn the key to start (yellow red wire)

go down to the starter and check for battery volts at the small purple/black wire on the solenoid when you turn the key on to ignition on. If not there could be a problem between this terminal and the coil +.
 

Lou C

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What's up with this buggy software! I wanted to correct what I wrote above. Looking at the wiring diagram, the coil positive gets fed by black/blue wire from the small terminal on the starter solenoid when you are cranking it over. Once the engine starts, the coil should be powered by the purple/red wire that feeds into the alternator wiring harness, it gets current from the alternator E (Excite terminal) but this does not provide current till the engine is spinning and the alt is generating current. That's why you have the black/blue wire from the solenoid connection to power it during cranking. When you let key go and the engine starts, the alt should be powering the coil.
 

ab59

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I am wondering if I had the plug , plugged in wrong now . I don't see a notch or alignment groove anywhere on the plug halves and when I was looking at it yesterday it looked like it could be plugged in at least two different ways . I will look it over a little better after I test the plug for juice today and them plug everything back together , then re test .
 

ab59

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Success --- I cleaned everything up, tested and plugged the harness back together and when I hit the key the engine fired up immediately and ran smoothly.
Thank you all for your interest and input --------
 

Lou C

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Great glad it was simple just put a hose clamp around where the 2 halves meet
 
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