[DCB_MINDED]

Don't take this the wrong way but: DO NOT USE CAR PARTS ON A MARINE ENGINE! Boat parts are "marinized" to prevent sparks and keep your boat from becoming a bomb on the water. Also, the muffs are good for determining SOME engine problems.... but without the added drag of pushing the boat through the water, it may not bog down. Just keep that in mind while diagnosing. Hope you figure it out, keep us up to date.

[DougR]

How's it going? I would try to fugure out whats going on before you worry about parts..
And I agree wth the above post....

-Doug

[guyjusthere]

You have to troubleshoot:

It's a fuel/spark issue
check spark plugs for cracks/proper gap [0.045]
check/change fuel filter
Check ignition/plug wires

STILL?
check fuel pressur & vac
Check/clean carb

Still?
Check Compression
Check Timing

Still?
bring to mechanic

[Eastleym]

I recently bought a 96' 190 Z SE and it ran great for the first few weeks. This past weekend my wife and I took a cruise from Dubuque IA to Prairie Du Chien WI (about 50 miles) averageing about 35-38 MPH. It was awesome up until my boat started the exact same problem. I fuel filter, fuel/water sep filter and added a can of sea foam but no dice. I delivered it to a shop this AM and will report back their findings. Hope it's not too major!

[V-side-down]

This may sound off the wall but what about a dead short. I was up @ Powell recently and was allowing the kids to get in between the wheel and me to drive. Long story short, it ran great all day or week and all of a sudden it would sputter & stall. I was thinking I got bad fuel, water in fuel all kinds of things. Here the kids had rotated the knob switches for eng comp blower and the switch for the run & park lights, also including the ignition switch. Somehow the knob switches had been rotated to the point of causing a bad connection in some butt connector wiring repairs which was done by the previous owner. Anyhow I tied a string around that particular wire loom and it ran great the rest of the last day. Apparently either the rough ride from running at speed and or the kids bumping or playing with the switches had worked things loose to the point it would intermittently cut out. Every time you hit a wave or wake it's bang bang and hard on wire connectors. Sorry to go on but on boats always consider wiring, especially when things do not seem to make sense.

[John Rush]

Did you all ever figure out the problem? Seeming to be having the same.
John

[Eastleym]

I had the same issue and replaced my ignition coil and the problem is long gone. I have put on many hours since! Hope this helps.

[CSofbuckeyelake]

I had a similar problem. Turned out to be the Oil Sending Unit wire was loose. I discovered this after i replaced plugs, cap and rotor, fuel filter...
The oil sending unit on on the right side of engine- not too hard to reach. The oil sending unit's job is to shut off fuel and spark if it senses low oil pressure- but my wire was loose enough that past idle- maybe vibration or whatever- lost contact and made it bog down and die.
Hope that helps.

[Jimh23]

Sounds like points to me.

[ColoradoDiablo]

No points , but viable shot!