2003 Nautique 196 Excalibur 330 engine missing

[PDK]

I own a 2003 Nautique 196, PCM Excalibur 330 with ~400 hours. Recently when putting it in the water and starting the engine, the engine was missing very bad. After increasing the rpms, the engine slowly smoothed out after a minute or two with the miss become much less noticeable. When returning the engine to idle, the engine idle was very rough. It seemed to run reasonably well after that between 2000 rpm to ~3250 rpms when the engine miss became worse. The rpm would slowly increase to ~4350 rpms, with still a slight miss noticeable. This has happened on the last two launches. On one occasion, the engine backfired once with the throttle wide open.

I performed the following checks:
Checked (iridium) spark plugs - good color (~150 hrs use)
Checked Compression - all cylinders the same, >175 psi
Checked cap and rotor - very good condition (~150 hrs use)
Drained FCC bowl - clean not waterare
Visibly checked plug wires - look good (original)
I did NOT check the timing.
I have added Techron the last 2 fuel tanks

The engine always seemed to run a little rough around ~1400 rpms, other than that it ran great. The boat and engine are very clean and have been well maintained.

Any help would be greatly appreciated! Is there anyway to run diagnostics on the engine, if so how and what kind of analyzer is needed? I would like to take care of this before I winterize it. Thank you!

[dkimball]

I would change the cap and rotor. I have a 2003 216 with the 330 and it died on me pulling a footer of the dock. It wouldn't start back up and I thought it was a fuel issue did a lot more checking than I should have and ended up replacing the cap and rotor and it fired right back up and has run fine since. I have heard that these engines need the cap and rotor changed more often than you would anticipate.

[SilentSeven]

Sure sounds like an ignition miss...maybe with a couple cylinders.

I'd look at all of the following:

- cracked plug insulators
- arcing plug wires
- distributor cap setup including signs of moisture
- put a timing light on it just to verify it's correct

Good luck and keep posting!

Sent from my Pixel 7 using Tapatalk

[jpwhit]

Replace Cap and Rotor unless they've been changed in the last few years. You can't tell if they are good by looking at them. They are notorious for causing this type of issue on that engine. The distributor on this engine also tends to have the ears for the cap screws break off. If that's the case, you will need this repair plate.

https://www.amazon.com/Dorman-90449-...s%2C249&sr=8-1

[PDK]

I will replace the cap and rotor with an oem replacement. Any thoughts using onboard engine diagnostics? Possible fuel related issues? Injectors? Thanks to everyone that has given me input!!

[JayG80]

I have to replace my cap every 12 to 18 months even though they look great. Cures the miss every time.

[PDK]

I had a little difficulty getting a cap and rotor. The first set I purchased was a AC Delco. It fit poorly on the distributor. I then purchased an Accel set and installed them. I have a setup that allows me to run my engine out of water. After first starting the engine it seemed to run fairly smooth cold. After a few minutes it started idling rough. Increasing the rpms it seemed to smooth out a bit, but it was not under load. I saw no visible arcing from the plug wires. I tried to check the timing, but it was not steady since the engine was swinging about 150 - 200 rpms at idle. I believe my issue still exists. Any thoughts? Thank you!

[Rednucleus]

Maybe ohm your wires if they have not been recently changed, or just change them

[PDK]

I will do that tomorrow, can you tell me what a normal reading is? Thank you

[Rednucleus]

I don't have numbers for you but hhopefully this link helps ...
https://www.repairsmith.com/i/blog/s...re-resistance/

[PDK]

I tested my wires today, #8 cylinder was 3 times the value of the others. I went to two local auto parts and the quality of the wires in my opinion left a lot to be desired. I did purchase a set and tested the resistance of the new wires and they were five times the value. I replaced #8 wire and ran the engine. It appeared to run smoother after a while, but the idle was still surging. I sprayed carb cleaner the idle air valve port a few times and it seemed to help. I ordered a set of PCM wires from Planet Nautique. I winterized today and Spring will tell the story. Thank you all for the input and happy holidays!

[PDK]

My issues are ongoing. I had my injectors cleaned and the issue improved and then my idle air valve failed. I have a replacement on order. Is there a diagnostic port on the 2003 Excalibur 330 to assist on troubleshooting. I have not located a port? Thank you.

[SteveDoc]

There is a port under the plastic cover on the engine right side looking towards back of boat right of throttle body. I believe it’s a 10 pin D shell with a male end plugged into it with just one jumper wire on the end. You have to use a marine engine diagnostic tool to troubleshoot the ones used for cars won’t work.

[SteveDoc]

PDK Last year I bought a software and cable package from OBD diagnostic inc they had a package for viewing info only for about $200 using a laptop. it worked good you can see I/0’s warnings and faults in addition to all the engine data needed for troubleshooting . Maybe others could chime in on anything better that you can use. Oh you need to know what ECM you have on your engine. It’s written on the bottom of the ECM.
Good Luck.

[PDK]

Thank you, I have my ECU numbers (MEFI-4). I will contact them next week.