Washing engine after fire...

[claud84]

Hi folks,


I need to get my old Yanmar 2QM 15 washed and bring back to life. About a year ago engine got on fire while crusing by the coast. I managed to put down fire using fireextinguisher. The engine itself is not destroyed, but electrical system needs to be replaced. How and What to use to clean it in the proper way? There is rust, powder all over it...


Thanks a lot,

[Wotname]

Remove the alternator and wrap some plastic around the end of the starter motor, secure with cable ties or duct tape.

Pour plenty of hot water and detergent over engine, scrub where you can or use a small pressure washer if you have one. Repeat as often as necessary. The idea is to get ALL of the powder and oil off the engine and as much LOOSE rust as possible.

Dry with a hot air gun or run for say at least 30 minutes.

Spray with POR paint.

This won't give you a professional paint job but it is a reasonable approach for an old engine. It will look tidy and cared for after this treatment.A 2QM15 doesn't run hot enough to need a high temperature auto engine type of paint.

OR for professional looking job -

Pull it out, disassemble into component parts, sand blast each one, paint accordingly and reassemble.

BTW, the 2QM15 is a great engine and worth the effort of the cheap and cheerful approach.

[JPA Cate]

Hi, Wottie,

Can you not vacuum up much of the powder? first? Or, it doesn't vacuum up well?

Oxalic acid and toothbrush for rust? Baking soda + water to neutralize the acid.

A garden sprayer might also be useful for rinsing it down. I used a garden sprayer and dishwashing soap to wash my house eaves before re-painting them, one time.

Good luck with it, Claud.

[Wotname]

Presumably the powder is from a dry powder fire extinguisher which is very hard to get rid of after a fire. Typically it is a very fine powder of monoammonium phosphate (MAP) and it works by melting in the fames and coating the inflammable stuff.

If it will vacuum, start that way.

If the hot water and detergent doesn't shift it, move onto Isopropyl Alcohol; 50/50 with warm water, not hot water as isopropyl alcohol boils just over 80C (175F).

Fans will help drying.

MAP is acidic and can be neutralised with baking soda (bicarbonate of soda).

[more]

First and important
close air intake with rubber caps for pipe or PVC wrap, couple time.
Wire is for change, remove all burned wire.
close eletric from Starter motor. Usually you have switch for engine start.or remove start battery.
High pressure wash with hot or warm water.
then spray some engine cleaner
again, warm/hot water wash

Now, you can use paint remover carefully only on metal parts if you wish to make them look like new. You can also skip this step.
For rust, use a phosphoric acid solution or rust inhibitor on a phosphoric acid base. Go to the paint shop and ask. Follow the instructions for your rust inhibitor. Usually, after the phosphoric acid base dries, paint overspray is applied to the engine. Also, ask in the paint shop.

[NorthCoastJoe]

My first question was it running when you used the fire extinguisher on it?

The chemical in the extinguisher will corrode/etch the interior of the engine if any got sucked in. If it was running when you hit it I would at least look down the intake manifold for extinguisher residue. If you find any I would pull the head and inspect the pistons and bores.

In my past life I was an engine builder and a firefighter.

[claud84]

Thanks a lot for your help. I have now enough information to move forward.

There are good people on this world