Workboat

Hints on diesel marine trouble shooting

Maintenance

In June the Practical Planter gave a trouble-shooting guide for petrol engines. Here is your guide for diesel marine engines. Keep it in your workshop for reference.

Ingine Won't Start

I. Starter Fails to Turn Engine; (a) Check all wiring and terminals. (b) Check battery voltage. (c) Examine solenoid controlled switch after removing sheet metal end cover on starter and clean contact faces. (d) Check that commutator and brushes are clean and that brushes slide freely in their guides. (e) Check spring load on brushes. !. Starter Rotates Engine but Engine will lot Fire: (a) Check that stopping lever is in "running" position and fuel pump priming levers are released from their latches. (b) If fitted, operate hand priming levers on each fuel pump and if fuel is not heard injecting, check fuel supply. (c) Make sure the cold start plunger is lifted, the fuel pump slider bar moves toward the flywheel or aft and beyond normal full power position. (d) If fitted, operate hand priming levers on the fuel injection pumps.

If the sprayers aren't heard or felt to vibrate, the sprayers require attention or exchanging. (e) Check engine compression by hand rotation of the crankshaft. If great resistance is not felt on each cylinder, the cylinders and pistons could have severe wear (ac

companied by excessive lubricating

oil consumption) or valves and valve seats require attention.

Ingine Misfires Or Appears Short

DF POWER (for diesels fitted with fuel lumps) Some fault or air lock in the fuel system is indicated. Firstly reprime the whole fuel system including the fuel injection pumps. If this fails, remove and inspect the diaphragm of the fuel lift pump or pumps and examine the suction and delivery valves. Re place faulty parts, if required, or fit service unit.

Keep this guide for easy reference

smoke from exhaust (a) Engine is in need of overhaul. (b) Sprayers require attention. (c) Valve or injection timing incorrect. (d) Air intake has become choked. (e) Interference with the normal full powered fuel setting.

Low Oil Pressure

This may be due to faulty gauges or to a damaged or faulty oil pipe leading to the gauge and it is desirable to check them against another gauge. If the gauge goes properly the following could be wrong: (a) Oil filter element choked or in need of replacement. (b) Severe dilution of the lubricating oil due to faulty sprayers or leaking fuel pipe connecting unions on sprayers. (c) High oil and/or water temperatures. (d) Interference with setting of pres sure regulating valve. (e) Leakage at oil pressure pipe unions. (f) Bearing failure. (g) Engine in need of overhaul after long service.

High Oil Temperature

Providing there is enough engine room ventilation, high oil temperature is only likely to be caused by some fault in the flow of water through the oil cooler. (a) Examine pipes and raw water filter for blockage. (b) Check that the water pump is operating correctly.

High Or Low Water Temperatures

Maximum temperature varies for dif ferent types of engines; if this maximum is exceeded look at the heat

exchanger, the cooling system and the circulating pump and check the fol lowing: (a) Slack driving belt on raw water circulating pump. (b) Blocked water passages and pipes. (c) Blocked filter on raw water pump circuit. (d) If the installation includes a keel cooler, check its pipes for damage.

Dynamo Not Charging

This could be because of a slack or loose drive arrangement. Check this and if it is working efficiently, inspect the electrical circuit as follows: (a) Check condition of battery. (b) Check all wiring and terminal con nections, including the spiral fibre insulation on commutator brush leads for signs of burning or charring indicating a short circuit. (c) See that commutator and brushes are clean and brushes slide freely in their guides and are bedding correctly on the commutator seg ments. (d) See that the insulation between commutator segments is undercut below the surface of the copper and that the grooves so formed are free from any deposits which may bridge the inter-segment in sulation. (e) Check cut-out for correct function, clean and adjust contact points if necessary.

If the electrical circuit is found to be working correctly the voltage regulator or dynamo windings may be suspect and should be subjected to a thorough bench test.