Engine Problems

Answers To Those

What are your problems with marine engines, power pumps, generators or other engine gear? Send us your questions and our technical expert will answer them through the columns of Practical Planter.

Corroding Exhaust Pipes

We are having trouble with cor roding exhaust pipes on our diesel launch. The original copper exhaust pipe (with discharge water going out astern) quickly corroded and a gal vanised iron pipe rusted, though not so quickly as copper. We do not want a hot dry exhaust or overhead pipe. What should we use?

A. It is now customary with wet exhausts to use a special rubber pipe.

Rubber is not affected by sulphurous diesel exhaust and salt water. The piping is made up to specific lengths by Australian rubber companies, and has moulded soft ends for fitting to the engine end to the outlet fitting on the transom. Provided these pipes are always operated in a wet state they will last for many years.

Pump For Irrigation

I intend to irrigate a section of my plantation property. 1 am told that bore water is available at a depth of about 35-40 ft below ground level.

Could you suggest a suitable and re liable pumping unit? I have no electric power for this operation.

A. You do not state the area you intend to irrigate or the amount of water required. As an example you can obtain a diesel-driven tur bine pumping set which will produce about 25,000 gph. With this you could use an air or water-cooled engine of about 40 hp. Price would depend on the make of the unit. If you send me the necessary details, I will arrange for suppliers to submit quotations to you.

Trouble With Diesel Engine

I have a diesel generating set on the estate and it is located on a very substantial bed. It is a smooth running set except for variations when I change power loading. I find this irritating. Also noise transmis sion and drumming are very notice able on the bed. Is it necessary to alter this bed or to enclose the set?

A. As a first step towards over coming the conditions you describe, I would suggest that you obtain some flexible mounting blocks which have insulating properties. It is not diffi cult to mount the set on the blocks, which, incidentally, are readily obtainable in Sydney. If you let me know the weight of the generating set and whether it is a single or a multi-cylinder power unit, I will pass your problem to the principal sup pliers who will quote you for the correct size.

Propeller In Poor Condition

We still use an ex-Army 40 ft workboat which has a well-used diesel engine rated, we understand, at 40 hp with rpm at 1,200, and a 2-1 reduction gear. Our propeller is in poor condition and we want to re place it. What type and size do you recommend?

A. We suggest trying a three-blade propeller of normal area approxi mately 27 in. diameter by about 23 in. pitch. This is assuming your engine is quite efficient, but should you feel that the power is down on the original rating reduce the pro peller diameter by \ in.

• Questions for this department should be addressed to: The Editor, Practical Planter section, Pacific Islands Monthly, GPO Box 3408, Sydney, NSW, 2001.