98 Yamaha 9.9 MLHV wont stay running

I have a 98 yamaha 9.9 two stroke tiller that i got in trade. It starts first pull but you have to rev the hell out of it to keep it running, it won't idle at all. I can tell the carb has been taken off in the past because someone used clear silicone to seal it back to the block. I am no expert but I am 99 percent sure there is supposed to be a gasket between the carb and the block. Im sure its sucking air there, is that my problem or should i disassemble the carb and clean it too? The motor is basically brand new I can tell that it hasn't been ran very much but it has sat for a long time.

I would suspect that the previous owner did the silicone gasket and it would concern me what other half *** work has been done to that motor.

Pull the carb off, get a kit for it and do it rite.

while doing that i would visually inspect the rest of the motor for any "handy work" the PO did.

Your motor is a 97..

https://www.boats.net/parts/search/Yamaha/Outboard/1997/9.9MLHV/parts.html

Yeah I checked the rest of the motor for work but it was clean and it was definately obvious that it was a homespunt carb job the way the silicone was slathered on there. He told me he had his buddy who is supposed to be a real good outboard mechanic redo the carb. I think he tore the gasket takin it off and put the silicone bandaid on it instead of gettin a new one. It was a good deal though the motor is nice and i traded it for a 250 dollar jet ski hull. your right its a 97 the end of the serial number has a w thanks.