Excalibur 330 misfire

I’ll try these suggestions tomorrow. Thanks guys for all the ideas!

Yes the miss is between 24-3400 rpms. Throttling up and slowing down, load or no load give the same results.

Same result testing #4 at the cap.

I will try a third cap today. I just don’t get it

Another new cap, engine surging now, gauge is saying knock sensor. Guess I’ll throw one of those at it.

All wires are where they belong, simple on this setup

Okay is there anything at all I can do with the dizzy without diag equipment?

I’ve never had the misfortune of chasing a problem like this. Your right, forever post with many different problems.

Do you have a knock sensor in place? It originally would have been in the water drain hole on the starboard side. They get removed for winterization, if removed and replaced with a pipe plug that could lead to the error.

Next step would be to make sure it is working- no breaks in the wiring and the threads are complicating the circuit (no excessive Teflon tape).   

if you have reliable spark now you might want to move onto cleaning the fuel injectors.

Is it worth trying a new knock sensor? Or is that just a stored code?

Knock sensors are relatively cheap - you could however test it before you replace it. I didn’t do anything other than replace my knock sensor to make the code go away. If the boat has been sitting cleaning the injectors- maybe replacing the orings and filters is a decent idea and not much more difficult than swapping them around.

Still chasing this problem. Put a new knock sensor in with no change. Been running non ethanol and seafoam thru it, changed FCC filter. Tried new wires, guess it’s time to drive it on the trailer and bring to New England Correct Craft.

Glad you figured it out.  

I scratched my head for days, sitting looking at this engine thinking wtf else could possibly be wrong? I’ve swapped everything to do with ignition, three caps, two sets of wires, coil, dist pick up, and fcc filter. Decided to try another set of plugs before pulling it out. Only thing I haven’t tried twice! Sure enough that was it. Misfire was gone and boat pulled to 5100 rpm’s. Could only get 4200 before. Something so simple all along….