Mercruiser 3.0 "missing"

[zuhl]

I noticed today that my boat is starting to misfire when I rev it high, above say 4K RPM. At lower RPM it seems to run fine, but it might just be that I cant feel. There is a noticeable power dropout intermittently, almost like a cylinder is not firing properly. I would like to change my plugs and wires and maybe even overhaul the carburetor. I tried to do a search for Mercruiser 3.0 but I came up with nothing. Does anyone know what is the proper plugs and wires for this thing and proper gap for the plug. Also, where can I get a carburetor rebuild kit? I am pretty sure it has never been done before so I figure it is time. Thanks!

 

[Lazy Daze]

Try not limiting your search to "3.0". The symptoms are common and will generally relate to all carbed engines.

There's many places that sell Merc products online - they'll have the right stuff. Do you have a local Merc dealer (Doesn't have to be Sea Ray)? That would be your best bet.

I don't change my plugs all that often - I never remember what they're supposed to be - I always have to ask, too. 35 should get you close, though.

Before you go and do that, what do your plugs look like? Maybe just try cleaning them.

I had a similar problem. Once the engine got good and warm, I couldn't go above 3,200. It would start hesitating and cutting out. Turned out to be the ignition module inside the dist cap.