"lee" wrote in message
...
Mariner idles fine but when throttle is opened she is jerky in mid range.
At
full throttle, is smooth but lacks full power. Motor is one year old and
fully serviced.
Any help appreciated.


"fully seviced"..............who by? If recently, take it back and complain.

I would check:
1. Condition of spark plugs
2. Points gap
3. Ignition timing
4. Dirty jets in carb, if multi-carb ensure the linkage hasn't slipped,
causing one carb to stay closed.

Hope this helps,
Brian