Mercury 90hp No spark when spun over??

moss2029

Recruit
Joined
Mar 1, 2014
Messages
4
I have what i think is a 1978 mercury 90hp with a new stator and has carburetor, when i go to spin the motor over i have no spark from any coil, i also have no idle stabilizer is this required for spark? ive tested my mercury switch and everything is good and grounded. If you guys know anything to help please let me know!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,623
Re: Mercury 90hp No spark when spun over??

A 1978 90HP Merc would be an inline six cylinder, with a distributor ignition. is that what you have?
 

moss2029

Recruit
Joined
Mar 1, 2014
Messages
4
Re: Mercury 90hp No spark when spun over??

A 1978 90HP Merc would be an inline six cylinder, with a distributor ignition. is that what you have?

im pretty sure it is, i have a couple of books on this type of motor but im not to sure if 1978 is the correct year.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
39,401
Re: Mercury 90hp No spark when spun over??

Pictures or serial # is required here.----Does it have a belt driven distributor with one coil ?----Or 6 seperate ignition coils ?
 

moss2029

Recruit
Joined
Mar 1, 2014
Messages
4
Re: Mercury 90hp No spark when spun over??

photo (2).jpg

and the serial number should be 5594657 and above
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,623
Re: Mercury 90hp No spark when spun over??

OK, ADI ignition, six coils. Likely late '79 or newer. Disconnect the mercury switch and disconnect the black/yellow wires from the two switchboxes. Crank her and see if spark returns. If not go on the CDIElectronics web site and run the ignition troubleshooting test.
 

moss2029

Recruit
Joined
Mar 1, 2014
Messages
4
Re: Mercury 90hp No spark when spun over??

OK, ADI ignition, six coils. Likely late '79 or newer. Disconnect the mercury switch and disconnect the black/yellow wires from the two switchboxes. Crank her and see if spark returns. If not go on the CDIElectronics web site and run the ignition troubleshooting test.

Tried that no go on that one, I went through the Cdi troubleshooting and after disconnecting the yellow leads from the rectifier I got a spark on the first coil pack but none of the others, while checking the voltage on the other coil packs the first coil pack quit sparking
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Mercury 90hp No spark when spun over??

How fast is it cranking? There is a minimum cranking speed of 300 RPM or the stator will not generate sufficient voltage to operate the switchboxes.

Make sure the battery passes load tests and is fully charged. Also ensure all battery cable connections are cleaned bright and tight, BOTH ends as well as the starter cable.

Then use a DVA meter and test stator output to the switchboxes while cranking. Compare your results with the chart for your ignition contained in the CDI Ignition Guide

ISSUU - CDI Electronics Practical Outboard Ignition Troubleshooting by CDI Electronics
 
Top