3.0 L Mercruiser no spark

[harleysilo]

Hi everyone!

1988 Celebrity 19.5' open bow v-hull typical family recreation boat.
3.0 liter Mercury engine

The boat

TWO REAL PROBLEMS

Problem #1 Slave or "assist" solenoid clicks 9 times out of 10 that you turn the key, on the 10th time engine cranks
Problem #2 Engine Cranks but will not start up.

Here's what I've done so far.

Solution for #1 Remove all connections to Assist solenoid, sand then till all pretty and shinny, and then reconnect them, cleaned post to. Did exact same thing for the Starter solenoid. I have a brand new battery, and my battery wires are clean and shinny and screwed on tight.

Solution for #2 Use following diagram to trouble shoot....

I could not generate a spark, so I followed the left side of the tree first (ignoring position of the points) and ended up with voltage present.

Then I tried the right side of the flow chart and found voltage as well.
So I bought a new coil. Installed it, cranked it, nothing.

I repeated the testing and could not generat a spark from the coil wire. Got no voltage with my tester on the coil wire either.

Anyone have suggestions?

Thank you!

Thought the coil was bad, according to my manual trouble shooting tree,

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

After reading some other threads here...

My saftey lanyard is in place.

I sanded between the points, pulled spark plugs, cleaned and guaged them. Distributor lobes are clean and shinny.

I have the same amount our voltage going to both the + and - terminals on my ignition coil with the key in the ignition.

 

[Haut Medoc]

Re: 3.0 L Mercruiser no spark

Welcome to iboats......
Replace the assist solenoid......
How long has the boat sat?...
So you have 12v at the + side of the coil with the key in the 'run' position?.....
You should probably get a real Merc manual for your engine & toss that Clymer's in the garbage.....​

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

Thanks, glad to be here.

Yes, just went out and tested in this manner....

Points open, everthing wired up, key in on position (guages giving me readings)

Voltage present at pos and neg terminal of new coil

Dissconnect neg wire on new coil that is supposed to go to tach, re check and pos voltage to both terminals of new coil.

Does the assist solinoid affect voltage distribution to coil, meaning if its bad could that be why i have voltage to both terminals of the coil.

Can I by-pass the assist solinoid?

Thanks again for you assistance.

Oh,and I keep writing pos voltage cause believe it or not I don't know how to read this particular voltmeter, I take a pic of it and maybe someone can tell me what it is displaying....

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

Welcome to iboats......
Replace the assist solenoid......
How long has the boat sat?...
So you have 12v at the + side of the coil with the key in the 'run' position?.....
You should probably get a real Merc manual for your engine & toss that Clymer's in the garbage.....​

On a side note, i'll be in seattle this Wednesday, and after noon i'll be looking for a half day charter boat to take me fishing, anyone have an outfit they recommend?

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

O.k. so here is my test,

and a close up...

Everyone be sure and get your laughs in.....

 

[Haut Medoc]

Re: 3.0 L Mercruiser no spark

O.k. so here is my test,

and a close up...

Everyone be sure and get your laughs in.....

OK,
I think the dial should be in the 'Black" 50 range....
I'm thinkin' that black would be for DC voltage......
Salmon season is closed except for catch & release......
Can't reccomend a charter, but Everett or Edmonds, (north of the city) have some.....
I don't think that sneaking in a half day is doable.....
There is no charter that leaves from Seattle itself to my knowledge....

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

Guess I'll need to get online for the fishing stuff then....

And changed the dial....

Testing the neg side of coil and this is the reading....

10 volts i'm guessing....points open, everything wired up...

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

So does anyone know what and or how I need to test now to figure out why i'm still not getting a spark?

 

[Haut Medoc]

Re: 3.0 L Mercruiser no spark

Your shift interupt switch is centered in the detent?...
When was the last time this engine ran?......​

 

[Coors]

Re: 3.0 L Mercruiser no spark

And a meter that didn't come from Harbor Freight, and is better, might give you a leg up

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

Your shift interupt switch is centered in the detent?...
When was the last time this engine ran?......​

I guess I'll have to look in my crappy manual to figure out what the shift interupt switch is to determine that it is centered first.

It ran last Fall, and at the beginning of last summer got new points/rotor/cap and condensor.

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

And a meter that didn't come from Harbor Freight, and is better, might give you a leg up

Well please do elaborate on how my Lowe's voltmeters reading, which according to your opinon may be off a volt or two, is causing an issue with my troubleshooting. Would you advise me to test something else is you saw a more accurate voltmeter testing the coil, or do you just want to make fun of my voltmeter and not offer any helpful advice? Many of the other threads I've read here suggest that all that is really neede is a test light.... such as this one.... http://forums.iboats.com/showthread.php?t=167035

 

[Coors]

Re: 3.0 L Mercruiser no spark

Well please do elaborate on how my Lowe's voltmeters reading, which according to your opinon may be off a volt or two, is causing an issue with my troubleshooting. Would you advise me to test something else is you saw a more accurate voltmeter testing the coil, or do you just want to make fun of my voltmeter and not offer any helpful advice? Many of the other threads I've read here suggest that all that is really neede is a test light.... such as this one.... http://forums.iboats.com/showthread.php?t=167035

it was a joke, son , it was a joke (Foghorn Leghorn) Chill; we all do it

 

[Haut Medoc]

Re: 3.0 L Mercruiser no spark

Actually, the interupt switch is in your first picture just above the red tag.....
Its function is to momentarily ground the coil, & that is why I'm asking.....
!0 volts is enough for spark, btw....​

 

[Coors]

Re: 3.0 L Mercruiser no spark

Digitals are better, but a pain to learn; as even humid air between the probes constantly burbles.
It was a joke; sorry.

 

[Reel Poor]

Re: 3.0 L Mercruiser no spark

With the points open check for voltage at the point contacts. If no voltage work your way backwards thru the wire connection at the points then on to the negative side of the coil. The black wire between the coil and the distributor could be broken.

If voltage is present (should be present on only one of the point contacts) close the points and check voltage again. If voltage reading is the same as point open reading, the points are not grounded. Causes: glazed point contacts, breaker plate (the plate the points mount to) ground wire broken, no distributor housing ground.

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

Actually, the interupt switch is in your first picture just above the red tag.....
Its function is to momentarily ground the coil, & that is why I'm asking.....
!0 volts is enough for spark, btw....​

O.K. so here is my interupt switch, to my knowledge it has not changed positions during this whole process, as I have not shifted the boat into gear, only pumping the handle to get gas flow in attempts at starting while it was in neutral....

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

points open check for voltage at the point contacts.... If voltage is present (should be present on only one of the point contacts)

This is the case, voltage present on the point connected to a black wire going to the neg. terminal of the coil.

close the points and check voltage again. If voltage reading is the same as point open reading, the points are not grounded. Causes: glazed point contacts, breaker plate (the plate the points mount to) ground wire broken, no distributor housing ground.

Once I finally got the points fully closed,I got a slight voltage reading, maybe 1 or 2 volts. It took me several tries to get points fully closed, discovered they can look closed but still was getting the same reading as when they are obviously open.

Here is a pic of my distributor....

and close up of points fully closed when I got the 1 to 2 volt reading....I had previously sanded between points...

Finally, regarding the clicking in the assist solenoid, when I jump the two large posts with a screwdriver it turns over immediately, so I am assuming that assist solenoid is bad (i've cleaned all posts and connections)

 

[harleysilo]

Re: 3.0 L Mercruiser no spark

Well, it's running. I don't know what was the problem, put in one new plug to check for spark again, and as it was cranked sounded like it tried to start with the on plug wire disconnected. Pluged it up and cranked it and it started.

So I guess I'll put the other three plugs in now, and pick up a new slave/assist solenoid tomorrow.