Dinghy (and other) Motors
by Peter F. Ten Haagen
(Jacksonville, Florida)
Dinghy (and other) Motors
by Peter F. Ten Haagen
Many things in life are better when they aren=t used very often, but others seem to stay in good condition with regular activity and that category includes outboard motors.
The average small engine gets plenty of use pushing your dinghy into town or out on a snorkeling adventure while you are cruising, but for much of the year it probably sits idle.
The tendency with marine engines is to count the
hours of use to determine the likely condition of things, but often an engine with very low hours can be in worse shape than one of the same vintage that has been around the track (or across the bay) more often.
Why is that?
First of all the salt air environment is punishing to all kinds of machinery when it isn=t protected. The insides of your outboard motor, where piston rings meet cylinder walls in very close quarters, are lubricated and thus protected from the atmosphere by
the oil you mix in with the gas (or the sump oil for four stroke models).
When not running, the protective oil inside your engine is drawn by gravity to any convenient low spot. Damp air is always trying to get inside your motor via the carburetor and without a coating of oil, it can pit and corrode the sensitive metals inside.
By regular use you not only keep the internal parts lubricated, but you also drive out the moisture that contributes it=s fair share to engine problems. As an additional bonus, regular use helps keep the various seals in your motor in better condition to better ward off leakage (out) and seepage (in).
Incidently, when you run your engine out of gas prior to storing it, you should note that when the gas runs out so does the lubrication oil in a two-stroke design. A better practice is to load up the gas supply with a good stabilizer and run that through the motor prior to storage.
If you are storing it for a long time, like over the winter months, you should remove the spark plugs and have someone pull the motor over a few times while you spray fogging oil into the plug openings. Fogging oil is designed to cling to the cylinder walls far longer than two stroke oil.
Here are some other ways you can help extend the useful life of your outboard:
1) Zinc anodes. Many smaller outboards don=t even come with a protective anode, possibly on the premise that a penny saved is many dollars earned over the sales of thousands of units. No matter how small your outboard, or how little time it spends in salt water, you should have a zinc installed below the water line to act as a
sacrificial offering to the gods of galvanic corrosion.
The bottom of the anti-ventilation plate, often incorrectly referred to as the anticavitation plate, is a good place to install a zinc. Just pick
up a small zinc (based on the size the plate will accomodate) at a marine supply outlet and drill and tap a pair of holes to line up with those on the zinc (you can also install it with bolts and nuts
if you prefer) being sure to scrape away the paint in the area of the plate where the zinc will reside.
The activity taking place is electrical in nature, so there needs to be good contact between the metal of the plate and the zinc for the zinc to do it=s job and be worn away in lieu of the motor itself. Once your zinc is installed, include it in your annual maintenance checklist and replace it when it is down to about 60% of it=s original mass.
About that anti-ventilation plate - it is there to prevent cavitation, but only the kind brought about by the introduction of air from the surface to the propeller blades. There are other kinds of cavitation that the antiventillation plate can do nothing to prevent.
2) Warm up period. Many people like to start their outboard and immediately nail it but this is bad for the engines=s insides. Let it warm up for a minute or so running at idle speeds to allow for expansion of the piston rings - this will greatly extend the life of the motor.
3) Shift gears smartly. Do not EASE an outboard motor into gear. The shift mechanism employs a clutch dog with sharp Aears@ on it that engage a moving gearset and thereby lock it to the propeller shaft.
The grinding noise you hear if you shift slowly is the ears rubbing against the mating notches of the forward or reverse gear.
Doing this routinely will eventually cause the hard edges of the ears to become rounded and the mechanism will begin to slip under load. Snap
your outboard into gear, and only at idle rpms.
