1977 Mercury 1500 not firing correctly

[Tweety285]

I have fire on number 1 spark plug but the other 5 only spark when I let off the switch. Help with the problem please.

 

[CaptnKingfisher]

"Only spark when I let off the switch". Can you explain that bit a little clearer? Are you saying they fire when key is in off position and you jump the starter?

 

[racerone]

Tried a new battery ?--------Or have your battery load tested.------Inspect starter for high amperage draw as well.

 

[rcb130]

If you have a distributor with a trigger, check the trigger.

 

[Chris1956]

Run the CDI Electronics ign test on your battery powered ignition system. You likely have a bad trigger.

 

[rcb130]

Chris1956, Did that already. All voltages normal except for DVA on green wire. 3.99 DVA. New trigger installed at same time as second CDI unit. I am looking for infor on what would cause a CDI Electronics unit to blow after a week. This is the second one.
rcb130

 

[rcb130]

Disregard above post. Thought it was for another listing.
rcb130

 

[Faztbullet]

Send it back to CDI and get another one. Had a customer go thru 3 units before he got it going.