2000 mercury 150 efi xr6 wont run on cylinders 2 and 4

[Merc 2.5]

Ya I wasnt think ecu anyway. Without reading thru again , what all have changed or tested

[eli]

If you have not done a leak down ,its time and should of been done first ,compression means nothing except what fuel to use ,i have had many motors with good even compression numbers and fail leak down ,last one had broken rings on 2 cylinders and would not run on the 2 cylinders with broken rings it was a 1995 evinrude 115 ,your rings and cylinder’s could be toast

[Capt.Insane-o]

Looked at reeds yet?

[FMP]

at this point ona computer last resort for me.. run it at night with cowl off.. take a well insulated screwdriver and start with tha plug wires and every wire associated with those two cylinders and see if got got any "leakage" anywhere

don't drop new plugs on the floor and use them

[zookimota]

reeds are good, new cdm's, new triggers, new plugs, have swapped ecu and swapped injectors around and it still doesnt run on 2 and 4.
i havent done leak down yet

[FMP]

Swap cdm , or "custom tuned" plug wires on 2,4

[zookimota]

swapped cdm from 2 and 4 and still the same

[Motv18]

Are you sure it’s missing. Some of the mercs can run smoothly like a v4 or or such

check all the plugs are on the right parts like before the electrical is the plug to the cdm is swapped between 2-4 it will fire and look good all day. Same with injection plugs. But never run.

[zookimota]

you can take plug wires off 2 and 4 while running and it makes no change in sound or rpm

[zookimota]

Still can’t figure out the problem with cylinder 2 and 4.
when first started after setting a day it idles great on all 6 cylinders for about 30 to 45 seconds then drops cylinders 2 and 4

[Merc 2.5]

Dont no enuff bout cdm stuff to help , but if u got good compression /leak down , then its fixable , maybe u should do leak down. Without reading thru again. U say its firing all 6 when u check ?spark

[zookimota]

it has spark on all 6 cylinders
when first started it runs on all 6 cylinders for less then a minute then drops 2 and 4
2 and 4 still have fire but wont run on those 2 cylinders