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Runaway Engine Woes


Ocean30
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Over the years injector nozzles do wear and carbon up so instead of getting a finely atomized spray of diesel droplets you get larger droplets and in bad cases jets of fuel. It is much harder for the streaks and large droplets to full combust so you can get smoke (in theory it should be blackish but sometimes looks grey or takes a sight blue tint).

 

Also on 1.5s and 1.8s the injectors have small hole that sprays sideways under cranking This aids cold starting, but this hole can and does block up. That makes the engine more difficult to start so you get a build up of unburnt fuel that produces white "smoke" for a while after starting.

 

It will do  no harm to get the injectors overhauled by a competent company and may well do some good. Make sure that top hat inserts stay down the injector hole rather than comes off on the injector. Get new copper washers and hook out the little crimped fire washer so you cab fit new ones. Make sure company are absolutely clear it is a BMC and NOT a Perkins. The nozzles are different lengths but look similar so sometimes the wrong one gets fitted.

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A good plan if you need to clean injector nozzles without removing them is what I've done on many engines over the years mainly diesel vehicles failing the MOT because of  excess smoke and my own Lister ST2 when I first installed it, it had been dropped off a tackle into the Thames and lain there for many weeks before being rescued. I first drained and flushed the oil in the engine and LH150 gearbox and reduction gear many many times, and turned it over with decompressors open to pump any water out of the bores. Then on a temporary rig started it up, mmm, running on 1 cylinder only, checked valve clearance and compression, both ok. fuel to both injectors ok. Then did my trick which I think I've mentioned here before. Remove the engines fuel filter bowl, empty it, half fill with fresh fuel and diesel fuel system cleaner 50/50 mix Redex I think it was. Pop it back on, a quick bleed and start up. After a few seconds the the other cylinder started to chime in, all lovely and good. Gearbox worked fine. Installed it in my boat and been perfectly good and 100% reliable ever since 2005.

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I’ve heard about that trick before! It’s probably never had any cleaner put through it to be honest. Can’t imagine fishing an engine out of the river and managing to get it started again! 

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39 minutes ago, Ocean30 said:

I’ve heard about that trick before! It’s probably never had any cleaner put through it to be honest. Can’t imagine fishing an engine out of the river and managing to get it started again! 

 

Once you think about it short term full immersion, say a few days,  is unlikely to do much damage. All the internal surfaces will be drenched in oil that has probably worked its way into the metal pours. Oil will be trapped between the bearings and shafts, while the fuel system will be full of fuel and is virtually sealed. The needle valves in the injectors will be watertight if in good condition. As long as you take the injectors or glow plugs out so any water in the bores can be expelled all is normally OK. If you don't do that the engine is likely to hydraulic lock and that can bend connecting rods.Then the sump needs draining, the filters changing followed by a couple of oil changes after shortish off load runs to purge any water from the oil galleries and the other parts.

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I salvaged a pair of 8/71s once,sunk ,and would have been OK ,except the underwriters did nothing with the hull for six months,then expected to get $50k for the wreck.

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