I had posted a week or so ago about an engine problem that I had. I cleaned the carbs, replaced the thermostats (per Cray, and many thanks for that) adjusted the floats to the recommended height, and installed new plugs. One thermostat was stuck partially open. I picked up 5 psi water pressure from changing the thermostats. I was running 15 at WOT and now I'm running 20, which means will allow me to raise my jack plate more to see if I can squeeze a little more performance out of it. Anyway....

I've owned the boat, nearly a year. It runs fantastic from about 1800 rpms to WOT. It has never ran good when running 4mph or slower, like I do while scanning with my SI. The motor loads up with unburned fuel and when I do give it throttle a huge plume of grey smoke comes out. When I putt around for more than 5 minutes, it really gets to running bad. I've put 4 sets of plugs in this boat in the 10 months that I've owned it. I put new plugs in it last week and after doing some slow cruising last night, they're fouled out.

The only adjustment screw on these carbs is the air/fuel mixture. I have it set more open than recommended so I'm leary of going any further. From my understanding, the more air, the leaner the motor runs.

I have checked the spark with a gap tester on each plug and they're jumping the gap that's recommended. I have not Ohm'd any plug wires, or coils, or anything like that.

One of my fishing buddies summed it up best last night. He said, "This motor sounds just like a street rod. It barely runs at idle and sounds like a beast when it's wide open."

Anyone have any recommendations?