How to Troubleshoot a Mercruiser Alpha One

by Breann Kanobi
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The Mercruiser Alpha One stern drive interfaces with the boat's engine to help run the boat. The drive is compatible with a variety of engines, up to 300 hp. It excels with gear rotations between 1.47:1 and 2.40:1 and works with propellers up to 15 inches wide. Typically, stern drive problems indicate engine problems, such as a broken carburetor or a clogged exhaust pipe. If you are unfamiliar with boat maintenance, take your Alpha One to a mechanic.

Step 1

Clean out the manifolds and exhaust pipes if the stern drive overheats. Inspect the manifolds and pipes for clogs and remove any clogged items with a rod or grasp the item with your hand and pull it out of the pipe.

Step 2

Examine the tubing that connects the stern drive to the engine. If any of the tubing is loose, reconnect it.

Step 3

Empty the engine of gasoline using a fuel pump. Refill the Alpha One compatible engine with fresh fuel. Old fuel sometimes pools in the tank or bonds with water, causing engine problems.

Step 4

Try to start the Alpha One compatible engine. Listen for strange noises. If the engine stalls or stutters, the problem lies with the carburetor or ignition. If the engine makes a strange noise, the engine likely suffers from broken chains, bearings or a lack of pressure.

Step 5

Remove the arrestor on top of the carburetor and examine the carburetor. If the carburetor is cracked or damaged, replace it. Move the Mercruiser Alpha One throttle cable forward and back while you examine the carburetor. If gasoline streams fluidly, the problem does not lie in the fuel system.

Step 6

Locate the distributor cap's center terminal. Grasp the coil wire with spark plug pliers and pull it away from the center terminal. Push the wire toward a ground point that does not touch metal. Turn the starter and examine the wire. If there is a spark, the spark plug wires and spark plugs are not the problem. If the spark wire fails to light, replace the spark plug.

Step 7

Clean battery terminals, if the engine fails to turn over. Put the boat in neutral and jump start the outboard engine's starter solenoid. If the solenoid fails to start, remove two or three spark plugs and attempt to start the engine again. If the engine starts, it likely suffers from exhaust problems.

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