Spring Commissioning: Gas Engine Start-Up Tips, Part 1

The following steps will help ensure that your outboard or sterndrive is ready for the season.

Step 1: Battery Install

Next up on the commissioning checklist is installing the batteries after they have been fully charged and load-tested with a voltmeter. Make sure that all positive battery terminals are covered to meet Coast Guard safety requirement, and use locknuts, as opposed to wingnuts, to secure the terminals to the battery posts. Wingnuts have a tendency to loosen over time, especially after a season of running through heavy seas.

(watch “Marine Battery Care & Feeding”)

Step 2: Visual Inspection

Once the batteries are hooked up, remove the engine cowling and check for any signs of rodent infestation. Mice and other critters love to get into engines during the winter, and they can do a lot of damage, especially to wiring. If you evidence of a rodent nest, inspect the engine wiring and fuel lines carefully.

Step 3: Trim/Tilt Test

At this point, test the engine’s tilt and trim mechanism to make sure it’s functioning properly. Do this by raising and lowering the engine using both the helm and engine-mounted trim controls.

Step 4: Priming the Fuel System

This article and the accompanying video focus on commissioning procedures for a 2009 250-horsepower Yahama 4-stroke. It’s important to point out that this particular engine may have different commissioning requirements than other makes and models, so always make sure to consult your owners manual or a certified marine mechanic before starting your engine after storage.

If you have disconnected the leads to the fuel pump, reconnect them now. (Note some engine manufacturers recommend disconnecting the pump at the end of the season as a precaution, as running it before the fuel system can be primed can damage or destroy the pump). Prime the system by squeezing the priming bulb to pump gasoline into the engine. When the bulb is hard, the system is primed.

Step 5: Cooling Water Source

After a check of the oil level (if a 4-stroke engine) it’s time to attach the “earmuffs” for supplying cooling water to the lower unit, and possibly a hose to the upper cooling-water port.

It’s very important to remain near the engine while it’s warming up. The earmuffs that supply water to the lower unit often vibrate loose, or can be pulled off if someone accidentally trips on the hose, and this can lead to the engine overheating. If you have small children about, keep an eye on them to make sure they don’t play with the hose or earmuffs.

Step 6: Engine Startup

With the water at full pressure and flowing from the telltales and propeller hub, fire the engine. After an initial sputtering, during which the winterizing fluids are burned off, the engine should quickly settle into an easy idle. After 10 minutes or so, check the temperature of the powerhead at several points with a sensor to make sure it’s heating evenly and within the desired range.

Step 7: Checking for Leaks

At this point, make another visual inspection to check for any leaks in the cooling system, as well as any oil leaks below the powerhead and around the fuel line connections.