Mercury 3.0 EST no spark

[Yz229]

Hello everyone,

Trying to fix my friends old 1994 Bayliner Capri 1950 with Merc 3.0.

It was running yesterday, did a compression test and now it won't run. First thing I did was checked for spark, and not getting anything, even from coil.

Right now I am running through the service manual "EST Ignition System Check", and I got to step 3:

3) Disconnect distributor 2 terminal "C/+" connector. Ignition switch ON , engine stopped. Check volts at + and C terminal of distributor harness connection.

Well, I did this and I get 0 volts on the C/+ connection. I do have 11.5v going into the Ignition Coil via the purple wire. Not sure why it's not 12.6v from battery.

And so, the next thing it says is "Repair wire from module "+ terminal to "B" terminal of black ingition coil connector or primary ckt to ignition switch."

I don't really understand what this is saying. Looking for any advice someone might have. Much appreciated!

 

[Scott Danforth]

Voltage drop is a bad connection somewhere between battery to ignition switch to kill switch to coil

 

[Yz229]

I tried putting battery voltage to purple wire going to coil, but still no spark from coil.

Still not really sure why C / + connector isn't getting any voltage at all

 

[Scott06]

Is shift interrupt switch tripped?man over board tripped

which wire is C/+ ? one of the two between coil and distributor?

http://marineengines4less.com/images/companies/1/EST%20Ignition%20Instructions%20-%20ME4L.pdf?1431462059320

can you id which one it is in the attached wiring digram ?

 

[alldodge]

3) Disconnect distributor 2 terminal "C/+" connector. Ignition switch ON , engine stopped. Check volts at + and C terminal of distributor harness connection.

Well, I did this and I get 0 volts on the C/+ connection. I do have 11.5v going into the Ignition Coil via the purple wire. Not sure why it's not 12.6v from battery.

Your saying EST but this looks a lot like TBV method
The EST troubleshooting is done with an ohm meter in most areas

 

[Yz229]

Is shift interrupt switch tripped?man over board tripped

which wire is C/+ ? one of the two between coil and distributor?

http://marineengines4less.com/images/companies/1/EST%20Ignition%20Instructions%20-%20ME4L.pdf?1431462059320

can you id which one it is in the attached wiring digram ?

None of them seem to be tripped. This has the two C / + wires I am talking about.

 

[alldodge]

Getting 0V on C+ means the module in the dizzy is not passing voltage and needs replaced

 

[Yz229]

Getting 0V on C+ means the module in the dizzy is not passing voltage and needs replaced

Ok thanks for the info. Wonder what happened In a day to make it go out and not getting spark. Also, when you say not passing voltage, is it getting 12v from 4 pin on distributor?

 

[alldodge]

I like this test


Coils rarely go out. Normally not seeing 12V on the + side of C would mean the coil is blown, but they just don't go very often but the module does

Just going from what your posting

 

[Yz229]

Thank you, I tried the pickup coil test in your last post and it seems to be fine.

Tried to measure the + side of C again and get .5v.

Really wish I had another module to test!

 

[Yz229]

Thank you, I tried the pickup coil test in your last post and it seems to be fine.

Tried to measure the + side of C again and get .5v.

Really wish I had another module to test!

Does anyone have a good source for the module?

 

[alldodge]

Don't know where is best price, but I would just look for delco EST module, they are all pretty much the same. That said, aftermarket is hit and miss

Looking at your pic again, I'll offer this. Using your pic, note the Purple brings in the 12V supply, if you don't see 12V on the Pink wire, the the coil is not passing the power, or the module is shorting it to ground.

Disconnect the 2 prong connector to the Dizzy to see if 12V shows back up. If it does then its the module.

 

[Yz229]

I checked it like you said, 12v going to coil on purple wire but nothing coming back out on 2 wire cable going to dizzy

 

[Yz229]

I ordered cheap aftermarket coil and ignition module, so we will see which one fixes it. Whatever was bad, going to order new OEM.

 

[Yz229]

Playing around with it more, all the sudden I have 12v on the C/+ wire. Still no spark. Next step in the service manual is to check the Tach for voltage, which I am getting. I don't have a test light, but while cranking, voltage to tach drops from 12'ish volts to 8-9v.

According to service manual, next step

"REPLACE IGNITION COIL AND
RECHECK FOR SPARK WITH
TIMING LIGHT. IF STILL NO
SPARK, REINSTALL ORIGINAL
COIL AND REPLACE
DISTRIBUTOR MODULE."
.

Good thing I ordered those two parts! Thanks alldodge for the assistance, much appreciated. Will update this post when I get the parts.

 

[Yz229]

Ended up going to O'Reilly's and found any GM Ignition Module. Found one for $37, and it runs again!

It ran really bad when I got it, so I cleaned the carb which was filthy, sonic cleaned, blew out the jets. Still ran the same. Tried it again to make sure, still terrible. Accelerator pump has a nice stream of fuel.

Problem is it will seem to run ok for a bit, then it idles for a bit and stumbles all over, back firing a bit through carb. Idle mixture seems to be happiest at about 1 1/8th turn out which is factory. 600-700 RPM idle and it diesels for a good 5 seconds turning off the ignition. Tried the old water down the carb trick, didn't seem to help much. If I take throttle linkage off and give it some rev's by hand it seems to be ok. I did put accelerator pump on the setting to give most fuel, may try to back that down.

Timing was at correct.

One of the issues is it has a full tank of gas. It was about half tank and I just filled up last week to the top, so at worst it's terrible gas mixed with fresh so it shouldn't be that bad.

 

[alldodge]

The way it keeps running its bad gas and/or compression
What were your compression numbers?

 

[Yz229]

The way it keeps running its bad gas and/or compression
What were your compression numbers?

About 170 each cylinder. Sure seeing a lot of white smoke from exhaust, maybe their is water in it.

 

[alldodge]

New motor should be 150, at 170 and white smoke I would agree water is present

 

[Yz229]

Trying to do some more digging on this carb. In seeing S/N 15396A4, but I can't seem to find anything on this carb. My engine serial is 0F076166, but it's not listing this carb being on it. Am I reading carb wrong? Pic attached.