8.1 power issue

Is there a certain cylinder that fouls or is it random? My plug fouled on cylinder #3. I also wonder if winter fogging is a factor.
 
I do not Fog for winter and still have had to replace plugs. the tunes are just super rich.... also I think lower RPM trolling kills them quicker personally comparied to 3500+ on plan running.
 
I believe that it should be .060. There should be a sticker on the top of your engine that has the proper gap listed, so double check me.
 
the plugs are gapped at that form the factory...
 
copb8tx said:
How did you determine you had a bad/clogged injector? What did you have to do to replace or clear it?
Click to expand...

Swapped wire, coil, and injector over to the starboard engine and the problem followed. Next ride out I swapped the wire and coil back and the problem stayed with the starboard engine. Replaced the injector and performance returned. I'm going to see if I can clean the bad injector to keep as a spare. Overall not too hard to replace. Release the fuel pressure, unplug a few connectors and unbolt the fuel rail. There is a clip that holds the injector to the rail. Just neen to work it off with a screw driver.
 
saopm said:
Swapped wire, coil, and injector over to the starboard engine and the problem followed. Next ride out I swapped the wire and coil back and the problem stayed with the starboard engine. Replaced the injector and performance returned. I'm going to see if I can clean the bad injector to keep as a spare. Overall not too hard to replace. Release the fuel pressure, unplug a few connectors and unbolt the fuel rail. There is a clip that holds the injector to the rail. Just neen to work it off with a screw driver.
Click to expand...

Thanks Tim. I'll be changing all my plugs this weekend and see where it goes.
 
saopm said:
Swapped wire, coil, and injector over to the starboard engine and the problem followed. Next ride out I swapped the wire and coil back and the problem stayed with the starboard engine. Replaced the injector and performance returned. I'm going to see if I can clean the bad injector to keep as a spare. Overall not too hard to replace. Release the fuel pressure, unplug a few connectors and unbolt the fuel rail. There is a clip that holds the injector to the rail. Just neen to work it off with a screw driver.
Click to expand...

So I replaced my plugs on my starboard engine with no joy. I'm still no quite sure what process you used to get down to the specific cylinder that had the clogged injector.
 
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Do you have a plug that looks like this?

IMG_4001.jpg
 
copb8tx said:
So I replaced my plugs on my starboard engine with no joy. I'm still no quite sure what process you used to get down to the specific cylinder that had the clogged injector.
Click to expand...

Simplest way with no tools is to unplug a spark plug wire one at a time and check the performance. There should be a significant drop in performance unless that cylinder isn't working well to start with. We use the Rinda software to duplicate the same thing through the ECM.
 
Thanks. I guess that'll be my next path.

Is there an easy way to disconnect the plug wire from the coil-pack instead of the plug? After a test run it's going to be awfully hot down there.
 
Yes. When I changed my plug wires I could reach them readily with the exception of one. Start with the easy ones...Or, find someone to borrow the software and cable from.
 
copba8tx, When you say "no joy", what specifically are you talking about? Is it running rough? Still can't get to full power?

The reason I ask is that I changed my plugs on 8/1. When I first pulled away from the dock, it was running very rough, worse than before I changed the plugs. I turned back, went below, and verified that all the wires were snug on both ends. I pulled away again and it was running a good bit better, but still a little rough. I decided to run it like that for a bit thinking that the ECU just needed a little time to adjust the air/fuel mixture table to account for the new plugs. It ran on plane just fine. Plenty of power, good fuel burn, clean exhaust smell. At idle speed it was still a little rough. I ran it that way again the weekend before last. When I got back it was still a little rough, so I decided that I might have gotten a bad plug. I was going to pick up one new plug and replace one plug at a time until I found the bad one. I didn't have time to get to Pep Boys to pick up another plug this weekend, so I ran it again that way. She ran smooth as silk all weekend. Smooth idle, no hesitation leaving idle, excellent power, smells normal. So... Maybe there was something else going on, but I'm starting to believe that it really was that the ECU a little time to adjust itself to account for the new plugs.

Has anyone else seen this before? Is it normal?
 
It's exactly the same as it was running prior to changing the plugs. It has a hesitation, slight pop and will only spool up to 3700rpms.
 
No idea about compression although I'm not too concerned about that. Boat has been perfectly maintained and only has 407 hours on it. Always run reasonably and not flogged.

I haven't changed the wires yet, that'll be my next move.
 
Are both your throttles at the same level at cruse? If not, then you probably have a dead cylinder. If they are equal at cruse and the problem is only at idle, then it could be your IAC starting to go. What are your idle RPMs? Do both engines match?....650 RPM?
 
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