96' Mercury 175 efi sluggish

[dynobo]

Engine has been completely rebuilt and lacks power on cylinders #1 and 2. Checked timing and all six are firing. Have swapped the ECU from a known good 200 efi and has the same results. Checked plugs, coils, wires everything ignition related seems fine. Have removed oil injection, idle stabilizer and oil module. With engine running I can pull the plug wires one at atime and the # 1 and 2 don't seem to make a difference. Would a broken crank seal ring between 1 and 2 cause this.

[T-REX]

How does the mota run on the boat, in the water???

All the cyls don't react the same when a plug wire is pull'd while idle'in on the hose, or idle'in in the water for that matter....

I would run it and see if it ia low on rpm or slow gitt'in up, then if it'z not act'in rite, I would start chase'in tha grimilin.....But make sure ya got a grimilin fo ya go hunt'in one!!:thumbsup:

[dynobo]

Thanks for the reply. The first time it was in the water it ran terrible because I did a dumb*** rookie mistake and emptied1 gallon of oil into the gas tank that I THOUGHT had 30 gallons of gas but actually had about 10 gallons so the fuel/oil ratio was about 10:1 at best needless to say the plugs were quickly fouled. I have since fixed the ratio problem and added new plugs but still the top 2 just seemed to not have any power at idle. I will drop it back into the lake tomorrow and see what she does. Thanks.....................:cheers:

[trashy]

I would do a spark check to see if those two cylinders are actually firing. If you have no spark on either one, then suspect a faulty trigger.

[dynobo]

Yea Ihave tested evrything ignition related. Used DVA to check stator,boxes and trigger and everything checks fine. Timing is about 21* at wot. There is a green wire that goes from the ignition circuit and I believe plugged into the oil module and I see on the wiring schematic that it ties in with the # 2 cylinder, I just left it disconnected assuming that it would alter the firing in the event of an oil system failure, but I no longer have the oil injection connected. This wire wouldn't alter the fuel injection timing would it.

[CharlieB53]

No, the oil module simply uses that signal to compare to the oil pump rotation signal, if the two signals do not match, then alarm.

In your case a cylinder leak down test will give you better indication of any possible seal problem.

[trashy]

Keep in mind, I am by no means an expert or a mechanic, so take it for what it's worth.

You keep saying that cylinders #1 and #2 "lack power" based on removing the plug wires and getting no change in engine sound/performance. If I understand correctly, you verified spark at those cylinders with a timing light.

I would get a spark gap tester to see how strong the spark is on those two cylinders. I suppose it could be possible to have two weak/faulty coils, but I kind of doubt it.

Are you having performance issues other than at idle? Perhaps some of these guys that know way more than me can help you out.