How to set the carburetor float

[willgordon]

My A4 has a new carb with very little time on it due to my inability to get the engine running right. After some new parts including the carburetor and new plugs, The engine starts very easily and seems to run very well but not for very long. After 30 minutes or so it starts to run rough and no longer starts easily, The brand new plugs are then dry but very sooty black. Replacing the plugs with brand new ones repeats the process almost exactly. I don't have much experience with engine repairs and I can't find a mechanic who will come to the boat or a marina close enough that I'm willing to try to motor there. Some friends say there is a good chance the float needs to be reset but I have no idea how do do that. Any suggestions or instructions would be greatly appreciated.

Will
Sabre 28 1974
Original A4 but with very low hours

[Dave Neptune]

First welcome to the MMI Forum.

There are a few things that can cause sooty plugs.
The carb is running to rich and could be a high float level, however in your case with a new carb i doubt the float level is to high.
The choke may not be opening all the way an easy visual check.
And least common but very possible is the exhaust is plugging up.

How does it run under a cruising load, IE have you lost power. This could be indicative of a plugged exhaust. How old is the exhaust? Since a new carb and good starting this is a distinct possibility.

Where is the idle air screw set? Should be about 1 1/2 turns out off the seat. Out is leaner and in is richer.

Do you see any fuel puddling in the carb throat?

Dave Neptune

[Al Schober]

The '30 minute' thing makes me think you have a failing spark coil.