AutumnChange the engine oil2 l SAE 10W-30 · First time after 20 hours. · every 100 hoursCheck the fuel filterevery 100 hours or every 6 monthsReplace the fuel filterevery 400 hours or every two yearsFlush the engine with fresh waterRun the carburettor dry or add fuel stabiliserFollow the manufacturer's instructions.Change gear oilMilky oil means there is water in the gear housing.Lubricate according to the lubrication scheduleStore the engine upright so that water drains out
SpringCheck the thermostatCarried out by a Honda dealer. · every 200 hours or annuallyCheck the gearcase oilMilky oil means there is water in the gear housing.Check the impellerReplace it if it is stiff or cracked.Check the propeller and anodesCheck that cooling water comes out of the tell-tale hole
Engine oilSpecificationSAE 10W-30Volume2 lNoteApplies to carburetted BF40A and BF50A. Newer BF40D and BF50D have different values.Honda Marine: Owner's Manual BF35A/BF40A/BF50A (PDF) ↗ (external link)
Gear oilSpecificationHypoid oil SAE 90Honda Marine: Owner's Manual BF35A/BF40A/BF50A (PDF) ↗ (external link)
Spark plugsSpark plugsNGK DR7EASpark plug gap0.6 to 0.7 mmHonda Marine: Owner's Manual BF35A/BF40A/BF50A (PDF) ↗ (external link)