Mercruiser 3.0 no spark at coil

[Justfishin1113]

Hello everyone! First, I wanted to say thank you for this forum and the great help it has been to me in the past, just reading through the resolved issues others have had.

I have an 87 Mercruiser 3.0l I/O. It will not start for me, but will turn over. First thing I checked was the fuel, and it is getting to the carb and seems to be flowing well. Second I checked for spark on the plug against a good ground, and there is no spark. Next I removed the wire from the coil to the distributor cap, placed a plug and wire where they should be and grounded it, still no spark. I am getting 12 steady volts to the positive side of the coil, and 12 on the negative when not cranking the engine. I figured this was a bad coil, and just replaced it without resolution to the problem. Any thoughts, or obvious things I am missing?

Thanks

 

[Bt Doctur]

Guessing you have points, and there oxidized preventing contact

 

[Justfishin1113]

I do have points in the distributor. They looked fine to me and are making good contact when I crank the engine. Should I take them out and sand them down?

 

[Justfishin1113]

I do have points in the distributor. They looked fine to me and are making good contact when I crank the engine. Should I take them out and sand them down, or would you suggest replacing them?

 

[Bt Doctur]

you cant tell by looking, put an ohm meter on the black wire going into the dist. cranking the motor will produce a pulsing effect on the needle if the points are making contact with each other.If nothing is seem on the meter, run some fine sandpaper
or a nail file across them and you should now have spark.

 

[Starcraft5834]

Guessing you have points, and there oxidized preventing contact

+1 what the Dr said....ive got the same engine.. after every winter sitting idle for 6 months, ive got to install new points/cap/rotor/condensor, don't bother sanding anything that's a "band aide",, might work, for a while, you can buy a tune up kit for less than $20.. I did,, installed parts in 10 mins and fired right over...

http://www.amazon.com/Sierra-Interna...ly+tune+up+kit

installed this.. perfect..

 

[Justfishin1113]

Thank you to both of you! Sanded down the points and is now running great. I will go ahead and order a tune up kit and install as well. Thanks for the quick replies and incredible help!

 

[Bondo]

I do have points in the distributor. They looked fine to me and are making good contact when I crank the engine. Should I take them out and sand them down, or would you suggest replacing them?

Ayuh,.... Welcome Aboard,... For testin' purposes, leave the points in place, 'n just drag a small piece of fine sandpaper 'tween 'em, 'n try startin' the motor,....

Points are an annual maintenance thing,....
Clean or replace, set the dwell, 'n timin',....

 

[achris]

If you have 12 volts at coil '-' when the points are closed, you have dirty points contact faces.