If it has been sitting for a few months there is a good chance varnish has built up in the carb. Gas turns to crap very quickly these days, even sometimes with stabilizer in it.

Recently happened to my 27, hadn't driven it for a month or more and took it to a show downtown. It started running rough and I had to keep the idle up to keep it running at lights. Finally, when coming down the street to the shop I cranked it wide open through the gears and it started running good and has been ok since then. I think whatever was plugging up the jets got blown through from running it hard.

The new gasolines really take their toll on carb and fuel systems.

Don