I love the magazine, read it cover to cover twice. Have you any idea why an ’89 Ovation would be getting too much fuel? I’ve gone through the carbs (several times) and have replaced the needle and the bowl gasket. Still too much fuel. Help!
Too much fuel – is this at rest or when running, or both? The inlet needle valve for the float bowl is the first place to start, sounds like you’ve been there and replaced the needle. I assume you’ve cleaned the seat and verified there’s not some crud or a plastic shaving stuck in there preventing a good seal. You’d want to verify the float level and function of the inlet needle and seat (on the bench) to see how it is working, or if it is working. The seat is non-replaceable by itself, as it is a fixed part in the carb. The carb body itself is no longer available according to the Yamaha parts system, and this was a pretty unique two-barrel carb for the Ovation.
If the problem is not flooding of the engine at rest and more of a rich-running issue, then there are two (one for each cylinder) fuel screws on the top of the carb. Index both of them by lightly seating them and counting the exact number of turns (down to 1/8 or 1/16 of a turn resolution) it takes to get there so you can always go back to where you were. I’d turn them down some and back out as needed to get rid of any lean stumbles or hesitations.
And of course, you’d want to verify the function of the choke system – a stuck choke can cause a rich running conditions, as well. Figure out exactly what happens when you pull on the choke level, if it is a plunger style or how the choke blocks an air passage to enrich the fuel delivery.