mercury 3.3hp outboard

[BOATKID]

going to bring tender engine home for mid season flush out.
Any advice on what to put in the water test tank to help get rid of salt deposits - eg - fernox

 

[Oldhand]

You don't need to take it home and you only need fresh water and the engine mounted on a bracket on a rail or still on the tender if in davits.

Tie a bucket so that it is firmly held with prop/lower leg in it and the protection fin of the outboard hard against the bottom of the bucket. Fill bucket with fresh water so the cavitation plate is covered. Check bucket attachment lashing round top of outboard is taking the weight of the full bucket, adjust as necessary. Keep additional supply of fresh water handy, a slow running pontoon hose supply is best. Start engine in neutral gear and run with throttle around the start setting for 5 to10 minutes, keeping the bucket topped up with fresh water supply. (Brief bursts if revs are acceptable but the exhuast will blow more water out of the bucket). Check water flow from the little tell-tale tube under the engine head, if flow is good, job is done. Turn off fuel and let carb run dry.

Empty bucket and remove.

Warning - do not perform with the propeller engaged, the bucket will empty instantly, usually over you!

 

[cliff]

Agree with Oldhand except for the top up bit - if flushing the little merc OB on the boat I top the bucket up with hot water and a little white vinegar to help dissolve any soluble salts in the engine. If flushing in the shop I use a 45Gal drum and leave the engine running in that, in gear, for about ½ an hour although I only do that once a season, just before its annual winter "service".
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[Ships_Cat]

With same engine I do it just as OldHand says (in our case on the temporary storage bracket on the rail). We have a very big bucket (which also gets used for laundry) and normally does not need topping up during the exercise.

If in a hurry I also do it with the leg of the outboard sitting on the bottom of the big bucket and the top of engine just held by hand in the cockpit - just be careful not to knock it into gear /forums/images/graemlins/grin.gif. That makes it quicker and easier to do if one is inclined to flush it after each couple of weeks of use (but I would not risk hand holding a heavier outboard).

John

 

[msimms]

If this is the same engine as the Tohatsu 3.5, and I think they are, underneath the engine you may find a bolt with a 10mm head and fibre washer, it may be marked with white paint, mine was. You can buy an adapter which screws in to this hole which you can attach a hose to.

To save time I made up a short length of hose pipe with the adapter one end and a standard hose pipe connector the other. Now only takes an extra couple of minutes to flush the engine through after washing the boat down.