mercury 90hp inline 6 no spark?

[jay_61074]

i have a 1977 mercury 900 90 hp inline 6 that i was preparing to get ready for the year..had it running days ago and now it will turn over but not start....dont think im getting any spark pulled plug and didnt get any spark to ground..........not much knowledge but can do a little any help im frustrated!!

 

[Faztbullet]

Re: mercury 90hp inline 6 no spark?

Check kill switch if one was installed, check for voltage at red and white wire at switchbox with key on. Have you boosted battery or reversed leads?

 

[jay_61074]

Re: mercury 90hp inline 6 no spark?

i dont beleive there is a kill switch...if there is i dont know where it is...battery is charged and polarity is correct...i hade it running fine 4 days ago...i checked power to red and white leads @ switch box with ign. on i have 12.5 v to both with ign. off i have power only to red terminal...

 

[Gomer50]

Re: mercury 90hp inline 6 no spark?

I would recomend going to cdi electronics website,they have a trouble shooting section for your type of ignition.Coil on your motor seldom go bad.On the distributor side of the switchbox is a mercury switch which grounds out the switchbox if the motor is tilted up can be defective.Check inside your distributor cap if the carbon thingy and spring are in good shape.Also take a good look at your three wires coming from the distributor to your switchbox.

 

[jay_61074]

Re: mercury 90hp inline 6 no spark?

well i found the tests online and ruled out tilt switch...and did not get any spark on the jumper wire test..not sure how to check the high tension lead (special tool needed?)...and i was getting 7.5 v on brown trigger wire, it says below 9v is bad switch box...i dont think im able to check the dva on the last step...i also took apart distributor and found traces of sand, slightly corroded contacts, and some gunk on carbon thingy...i put back together and still no spark...i now have a switch box from cdi but not exactly sure how to in stall it this step worries me--->11. Connect the new high tension lead from the distributor to the new coil mounted on the plate. WARNING: DO NOT
CONNECT THIS CDI MODULE TO THE OEM COIL AS SEVERE DAMAGE TO THE CDI UNIT WILL RESULT. i think im close to figuring this out!!

 

[jay_61074]

Re: mercury 90hp inline 6 no spark?

with all that said i attempted to put in the new cdi switch box..it was a little more complicated than i thought...couldnt just switch wires over and i figured out that it also had a new ignition coil mounted on with the new switch box..it you are doin this change over make sure you use the high tension wire which runs from the ditributor to the new ignition coil...i also took out mercury switch...and discarded the red wire from the wire harness as directed...after installing it started right up!!!!! sooo happy now hope this helps others....thanks guys for all the insight....

 

[Jeff Lindquist]

Re: mercury 90hp inline 6 no spark?

i have an 82 80hp mariner and i am experienceing similiar problems. would your mercury switch happen to have been a small blue sealed unit on the starboard side of the motor and mounted on about a 45 degree angle?