No spark - MerCruiser 5.7 lt '86 Alpha 1

DTM

DTM

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Motor just died at idle, could not restart. Electronic ignition. Plenty of fuel to carby. Thought it was the coil, changed coil, still no go. Is there a master fuse? Any suggestions? Thanks
 
achris

achris

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

One of the problems I've seen with those ignition systems, especially in the Indian Ocean :) is the terminals on the modules get corroded and loose electrical integrity...

Chris.......

If you want to pull the module out of the dissy and bring it to my place (near Jandakot), I'll resolder them for you (free).
 
DTM

DTM

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Hi

I'll check on youtube how to remove it because I can't get the roator button off. Thanks for your help.

- Danny
 
DTM

DTM

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

I just put a multi-meter onto the coil and there's nothing. I also pulled the harness and there's power on the motor side of the plug.
 
E

ENSIGN

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Before you start replacing parts check for 12volts on the positive side of the coil with the key switch turned on(purple wire)Also make sure the lanyard switch is on.
 
DTM

DTM

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

I put the multi-meter on both the positive and negative sides of the coil but there are no volts at all. The lanyard switch was on. I have a Quicksilver 3000 shifter and it has a run and off switch only.
 
achris

achris

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

There is a TB-IV trouble-shooting chart in the service manual. Follow that to determine where the problem is...

attachment.php


Just click on this and it will download (It's the TB-IV flowchart)

View attachment TB-IV flowchart.pdf

Chris......
 

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Don S

Don S

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

DTM said:
I put the multi-meter on both the positive and negative sides of the coil but there are no volts at all. The lanyard switch was on. I have a Quicksilver 3000 shifter and it has a run and off switch only.
Click to expand...

Put the red meter test lead on the + terminal of the coil, and the black test lead on a good engine ground, NOT the - terminal of the coil.

Does the engine still crank over ok? If so, there are no fuses causing the problem.

If you have no power to the purple wire on your coil with the key in the run position, you need to check voltage at the following places as shown in the picture below. (just a generic ignition system picture, not exact to yours)
This is done with the red test lead on the terminal being tested, and the black test lead on a good ground.
If the engine cranks over ok, check terminal 5 on the ignition switch to verify you have a good ground for your meter. Then check 6, 7, 8, and 9. to find out where the voltage is missing.

ign wiring.jpg
 
grewvin1

grewvin1

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Have twin 5.7L 1987 alpha 1, had bad coil got new one, engine then would not start just crank, bad new coil got another one, then decided to put new coil on other engine as well, that engine would not start put old coil back on, engine runs fine. Never had such bad luck with coils in my 40yrs of boating will be a while before I trust em again. They seem quirky.
 
DTM

DTM

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

I have checked the way you have told me, I have 12 volts at the coil and I removed the purple wire from the coil and tested it on its own and have 12 volts there as well. Shall I remove the rotor and the module - is that the next step?
 
Don S

Don S

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

DTM said:
Shall I remove the rotor and the module - is that the next step?
Click to expand...

No, now you are past the first step in the troubleshooting guide. Chris posted the troubleshooting chart, perhaps you missed it. Here it is again.

attachment.php


TB4.jpg
 
DTM

DTM

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

I tested for spark, grounded the white/green wire and have spark at the coil. Have removed ignition sensor, is very corroded. Whats the best way to clean it up or can Chris salvage it?
 
Don S

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Pull the whole distributor and take it to Chris to have a look, he's only around 45 minutes away.

Personally, if it's that corroded inside the distributor, then it's probably due for a new module and some cleanup. Make sure the distributor bushings are in good shape while you have it out.
 
DTM

DTM

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

I think it's time for a new module. I've cleaned the distributor. All looks good except for the module. I'll try that. I don't trust this old one...
 
achris

achris

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Bring it to me and I can have a look at it. I have successfully resurrected them in the past. :)

Chris....


Don S said:
take it to Chris to have a look, he's only around 45 minutes away.
Click to expand...

Been playing with Google Earth again???
 
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Don S

Don S

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Actually, just Google maps.
Went there and found this.



Across the street looks more like I would expect your place to look like. With a boat
 
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achris

achris

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Take a step to the south and then look west, that big shed in the back, that's where my boat is (sometimes) :D :D

Tom's boat (over the road) hasn't moved for about 6 years... (It's got a 470 in it :facepalm:)
 
Don S

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Ahhhh, got it. Now I can find you when I get there.
 
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DTM

DTM

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Re: No spark - MerCruiser 5.7 lt '86 Alpha 1

Thanks Chris and Don. Bought a new module, she's a goer :))) Only problem is the distributor has moved so I have to retime it. Is it 8 or 10? Thanks Chris for the offer of resurrecting the old one but happy with the new one as it is all sealed with metal parts exposed.
 
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