Did you set the floats while it was sitting on the trailer, or while floating in the water? Wondering if the attitude sitting in the water is markedly different, resulting in the float being too high, which might explain the fuel dribbling issue. Other thing might be fuel pressure issue, if too high could overwhelm the needle/seat, although I would expect extreme flooding with this.

Pressure gauges may tell the tale, although it's also possible that you have an ignition problem in addition to the carb problems. Do you still have the original HP500 carb?

Good luck!

Possible that the fuel dripping in the carb, is dumping fuel, bogging it down, dumping fuel, bogging it down...?


Fuel dripping could be from several things.

#1 Float set too high

#2 dirt or something stuck in the needle and seat

#3 too much fuel pressure (I doubt thats your problem though)

#4 loose bowl screws causing metering block gasket to leak fuel, or simply bad metering block gasket.

Did you have any backfires through the carb? If so, possible that the power valve is blown. That can also cause dripping fuel and rich running.

Set the float levels in the water yes. Have origional carb i could not figure out whats wrong with it, it kept dumping fuel in the primary venturis (i think theyre called the rings when you look down the carb) so bad that it wouldnt idle. Going to swap carbs tmrw am and go for a run. when i remove sec sight plug float level is right at the bottom of the hole. metering block gasket is new, carb is 2 weeks old. ill swap carbs and see what happens

Starting to sound like this might not be the carb's fault. Went back and read all the posts, and it sounds like the original carb had a similar issue. Starting to wonder if somehow it is getting too much fuel pressure on that one engine. Is it electric pumps or mechanical pumps mounted on the seawater pumps?

Has mechancial mounted to the sea pump. I have the metal fuel lines hp500 come with stock. looks like there is a small allen plug i can put a fuel psi guage in. ill let u know what i find

8 lbs of fuel psi. Little high correct?

My brand new merc pump delivers 8 and carb has no trouble anymore

8 psi is totally fine. Actually, 7-8 psi is perfect. You don't want to be higher though.

If the idle speed screw is opened too far you will have enacted the main fuel system and thus fuel will come out of the boosters. I'm assuming these are what the OP is calling the 'ring.'

If there is too much fuel pressure or the float is set too high or the needle and seat is stuck, the fuel will come out of the vent tube.

OP - don't take this wrong but your actions on the new carb (jetting/metering block changed over from old carb) and some of your terminolgy tells me that you don't know all that much and it may be time to look over the shoulder of someone who knows more.

I learned without someone like that but it's not the faster nor cheapest way to do it.

We can only help so much from here. Our hands can not go thru the computer screen - if you know what I mean.

Watching the fuel pressure gage while running , when it bogs, is what we wanted you to do to see if it's changing.