Spark Plug Question

[mjr119]

I replaced my plugs a few weeks ago (AC Delco, not sure of the part nubmer, I think I got it out of the manual, will need to double check).

The boat immediately started running kind of rough. Like it has a slight miss. It is only noticeable at idle or barely cruising below about 10 mph. If you throttle up to wakeboard speeds you cant feel it. it may still be happening, but it isnt noticeable like at idle.

When I had the boat weighted heavily for surfing, it was extremely noticeable! I could hear it cutting out while surfing.

Any ideas what could cause this? I did not replace the plug wires. Could it be the plugs?

Which plug is everyone else using?

[gregski]

What gap did you set?

[mjr119]

I did not change the gap. The plug specs were the same as what the manual calls for. I realize that they could be off from the factory. I didn't check them. Could this be the issue?

[gregski]

My experience with regular plugs is that the gap is not set by the manufacturer. I guess I don't know for these. I never install new plugs without checking.

Also, were the new plugs the same length as the old plugs?

[mmandley]

If you made sure the same gap was used for the new plugs as the boat manual calls for but you now have missing, you might have a damaged plug wire. This happens quite a bit when replacing them. If any of them were hard to remove, you might have broke the connection point from the wire to the connector on the plug.

My bet would be to replace the wires as well.

[brain_rinse]

Post the specific plugs you used and check the gap on one of of them.

[brain_rinse]

They will not have what you need. The plug wires are extra long.