I need a user manual for a starcraft inboard outboard boat. I need instructions for the combination throtle/outdrive/shift control. thanks

I would look up a Websearch for the brand of motor and the year and engine size. Marine engines have different camshafts and timing is different than on an auto engine. You would look up Mercruiser if it is an inboard/outboard outdrive and has Mercruiser emblems. Same for Volvo or OMC embled outdrives. Ford makes the basic block but the specs go by outdrive makers.

This is because the gearing in the outdrives make a difference in what the engine needs to do.

Download a repair manual from MarineEngine.com Outboard Motors Boat Parts Marine Engines Inboard Boat Motor

There are videos all over YouTube that cover this subject quite nicely.
winterizing an outboard motor YouTube

Try here,
Outboard Motors Boat Parts Marine Engines Inboard Boat Motor

They are motor motor manufacture specific but aftermarket controls are available. If you want an original, google used outboard parts. I know of a few used parts houses

The main types of engines when it comes to boats are: steam engine, gas turbine, diesel engine, steam turbine, and gasoline engine.

remove sending unit turn on key switch work sender by hand watch gauge should work evenly very eratic change sender

What you need to do is a Web search for the brand of inboard/outboard or outboard motor you have. For instance "Mercruiser trim solenoid" and the aftermarket companies that supply those parts will appear.
Also if you have a Marine Salvage place close, you can take your solenoid and match it to a used part.
Or once you have a part number you can find parts on Ebay or Craigslist.
An outdrive from a Cobalt can be the same as any other boat, just get the correct year and Series.

The first thing I would do is disconnect the steering at the transom. You want to find out if the problem is in the helm(steering wheel) or in the inboard/outboard pivots.

When you turn the wheel after the disconnect, it should not be hard. There is a set screw in the steering assembly either above or below the dash. There should be enough tension so the boat does not wander but not enough to be terrible to steer.

Next go to the outdrive. Without the steering connected, the outdrive should move with minimum resisitance in either direction. There are pivot points on top and bottom that should have marine grease at the start of each season.

You have a 21 year old boat. The driveshaft in the Inboard/Outboard should be greased every 2 to 3 seasons and the watertight bellows can be inspected at that time.

Now if the steering is even worse under power, you need to adjust the fin that drops down behind the prop. This part controls Torque steer so the outdrive is not trying to turn on you and wants to stay straight. If you do not have a problem leave it alone.

You can get an estimate for the driveshaft service and greasing U-joints and inspecting the bellows. They should grease the pivot points then too. I am told its about a 2 hour job. In my area its 60-70 an hour.

Thank, but I have managed to get manual on engine