It's never ceased to amaze me how some people can spend thousands of dollars on a new outboard yet fail to treat it as a precision piece of machinery.

The break-in or running-in period between pre-delivery inspection and first service is the most crucial part of your outboard's lifespan. During this period the engine literally wears itself in and every moving part of the engine is really 'working' for the first time...

Thus care should be taken to ensure this process is undertaken according to manufacturer's recommendations. If it doesn't the motor will likely never live up to expectations.

My very first outboard, a 1969 Johnson 1.5, is still in excellent working order because it was run in carefully. Sure, some components have been replaced, but the original crankshaft, piston bearings and piston rings have lasted all these years!

Apart from motors which have integral cylinder blocks and heads, all motors require cylinder-head and exhaust cover bolt tightening at the first service. And apart from Honda's BF2D, all four-strokes need their valves adjusted for correct clearance or they will never develop full power.

It's easy to understand how new boat owners get confused, however. Contacting outboard manufacturers and interviewing dealers for this column proved very interesting as many dealers disagreed with manufacturers' recommendations!

TWO-STROKES
According to Mercury Marine, its premix Mariner/Mercury models require only one hour of break-in on the normal 50:1 petrol/oil mix. But dealers interviewed said this was inadequate for a long lifespan and suggested one 25lt tankful of 25:1 for motors up to 6 hp and two tankfuls for motors over this size. Alternatively, 10 hours on 25:1 should suffice for all premix motors, with a 50:1 mix to be used in the fuel tanks of oil-injected models during this period.

Force outboards should be run in on 25:1 for the first five hours and, as with Mariner/Mercury models, throttle settings should be varied every 15 minutes.

OMC (Evinrude/Johnson) recommends one small remote tankful (11lt) up to 5 hp and two (22lt) up to 8 hp. Over this size it requires two normal remote tankfuls (45lt) and with OMS (Oil Management System) motors, a 50:1 premix is used in the fuel tank for the first 10 hours. One minute of Wide Open Throttle (WOT) operation in every 30 is also recommended, as is keeping the engine between half and three quarters throttle and varying the throttle settings every 15 minutes.

OMC's FICHT models are considerably easier to run in after the first hour or so they should be kept between 2000 and 4000 revs with short bursts of WOT. The management system in these motors automatically doubles the petrol/oil mix for the first five hours providing the revs are kept above 2000.

Japanese manufacturers still rely on owners keeping an accurate record of time and recommend doubling the petrol/oil mix for the first 10 hours, after which time the motor is given its first service. Suzuki, Tohatsu and Yamaha all recommend 25:1 for 10 hours, though with Tohatsu's 2.5/3.5 it's five hours on 25:1. With oil-injected Suzuki and Tohatsu outboards a 50:1 premix is used in the fuel tank for the first 10 hours, while Yammies need a 100:1 mix.

Suzuki's dealer network was less than co-operative, but Tohatsu dealers stressed not to use WOT in the first 10 hours and to keep throttle settings to less than three quarters. Yamaha and its dealers recommended WOT one minute in every 10 after the first two hours, followed by no more than five minutes at a time until after the first 10 hours. The throttle setting must still be varied every 15 minutes.

FOUR-STROKES
Honda and Yamaha still recommend running in their four-strokes at low to midrange throttle for the first 10 hours, after which the oil and filter must be changed.

However, OMC recommends the same procedure as its two-strokes, one minute of WOT operation in every 30 after the first hour, while varying throttle settings every 15 minutes. And unlike Honda, a low viscosity (thinner) break-in oil is used for the first 20 hours before switching to the normal Winter or Summer oil. The first service is at 20 hours or three months when the oil is changed and the filter cleaned or replaced.

Again, Suzuki dealers had no comment but their Tohatsu counterparts said the break-in period for their four-strokes is 10 hours. Both Suzuki and Tohatsu advise servicing at 20 hours, when the oil (and filter is fitted) must be changed.

CONCLUSION
As with most things in life, prevention is better than cure and any outboard will last much longer and perform better if a little care is taken during the first 10 to 20 hours.