Lost spark on cylinders 1, 2 and 5 (2001 mercury 150 carb)

[Jon1229]

Last week I noticed my WOT rpm drop from 5500 to 4800 so I checked for spark and compression. All 6 cylinders were between 120 and 125, and every cylinder had spark. Today, I was out on the water and lost spark in cylinders 1, 2 and 5. I assume these problems are related. On my way back to the dock (idling) I noticed the boat gain a little of its pep back and the three cylinders had spark again. What do we think? Power pack? Trigger?

thanks!

 

[GregCO]

Last week I noticed my WOT rpm drop from 5500 to 4800 so I checked for spark and compression. All 6 cylinders were between 120 and 125, and every cylinder had spark. Today, I was out on the water and lost spark in cylinders 1, 2 and 5. I assume these problems are related. On my way back to the dock (idling) I noticed the boat gain a little of its pep back and the three cylinders had spark again. What do we think? Power pack? Trigger?

 

[Jon1229]

Greg,

I can only see that you quoted what I posted but I cannot view your reply message. Would you mind reposting it for me? Thank you for your help.

 

[GregCO]

It sounds like the pack is possibly beginning to fail. It’s not uncommon for them to work while cool and start to fail as they heat up during use. Turn them off and let it cool and it suddenly works again for a bit. Have you checked voltage to the system?