Yamaha F90 Hard Shifting (Intermittent)

I was out about 15 miles in the Gulf last Friday and circling a bridge span at about 2000 RPMs and when I backed off to neutral the engine stayed at 2000 RPMs. I shut the engine off and restarted and it operated at normal idle. I didn't have any more problems for several hours. When we called it quits for the day I started the engine and headed in to Panama City Marina. The engine ran flawlessly at 4400 RPM and 25 MPH all the way back and never missed a beat. Before we passed through the no wake entrance to PC Marina I throttled back to just above idle speed and the engine started bucking/shaking and trying to cut off, I shifted to neutral and the engine still was trying to cut off. I tried to shift forward and it took about five or six times the normal amount of pressure to get it in gear. I made it over to the docking/launching area and had to again really put a lot pressure on the control to get it into reverse and not ram the dock. I shut the engine off while my fishing partner went to get the trailer. when he backed the trailer down I started the engine and everything was back to normal. Shifting and engine was fine for several forward and reverse shifts while positioning to get it on the trailer. The control again became very difficult to move as I drove onto the trailer. This being well above my capabilities to work on I put it in the shop the next day. So far I need I new VST filter and fuel lines which would account for the bucking and shaking. The shifting problem so far is under the "can not duplicate) category. Question? What would cause the shifing/high RPM in neutral problem that would correct itself when the engine is cut off and then restarted? The lower unit seems fine and there wasn't any clanging/banging from the lower unit. The oil, filter, lower unit and fuel water seperator have been changed every six months for the past six years. The shifting problems occurred at normal idle RPM. Would appreciate any input. The events happened exactly as stated. What happens when an F90 is shut off that would reset the idle and unstick the control lever? Also have had to jiggle the throttle for the last year or so while holding the key over to get the started to fire. Usually about 1/4 inch up or down to make contact. Turning the key always turns the accessories on, just have to bump the throttle to make contact with the starter.

FLCoyote
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