Starting switchgear on a Parkstone 21

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I have just bought a 1965 Parkstone Bay 21 and am now sorting it out. It has a Mercedes OM636 diesel engine - i.e. a taxicab engine.

There are two issues that need sorting immediately:

1. The air filter has been changed for a simple plastic cap which has an open meshed gauze to stop larger foreign bodies entering the intake, but no element to filter out dust. I have been told this is 'normal'. It's certainly not normal in my experience of engines. I vaguely remember being told that these engines had oil bath air filters. Further, there is a pipe, I believe it's called the crankcase breather pipe, that ends right by the filter. I've been told this should be plugged into a hole in the filter (currently there is no hole) so that the gunk from the crankcase goes into the engine and is burnt. Again, this seems odd to me.

Any info on diesel air intakes would be most appreciated.

2. The engine has glow plugs but they are not working and I have been told that if I continue to start the engine via long cranking sessions I will ruin my alternator. There is a strange item on the dashboard with 'Heater' written next to it. It has holes in it and I've been told should warm up when the engine is turned on. But, the key to turn on my engine is a strange one that no one seems to have seen before. It's a thin metal rod grooved at the end to form a small ball which is inserted into a hole. It has several positions:

Engine off:
a. when half pushed in, nothing happens.
b. When pushed in fully, the alternator light comes on, I presume warning that the alternator isn't charging.
c. the key can now be turned to two positions, but neither does anything. However, until the key is in this position the engine won't start. To start the engine a lever on the other side of the dashboard is twisted and the engine starts cranking and eventually starts.

At this point the alternator is charging with the light on. I can take out the thin key, the alternator light goes out, (but it's still charging) and the engine won't stop.

The engine is stopped by opening a hatch and pulling a stop knob.

Any elucidation as to why my glow plugs aren't working and what the positions on this darned key are for, or remedies of any kind (i.e. total replacement?) etc would be most welcome.
 
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unable to assist with the "electrics" but the air filter sounds about right (not much dust in boat engine bays) if you are turbo'd then the crankcase breather into the filter not a good idea, either breath outboard or a 2 litre pop bottle in the bilge with holes around the top to allow "breath" out but will catch the solids.
 
Hi,

To start with the good news; the pull-knob to stop is quite standard on this engine, (and many other small marine diesels).

Try www.west-4x4.demon.co.uk for bits. They may well be able to give you advice as well.

Mitchell put lots of OM 636 s in the PB 21, mainly because he was a Merc agent. Many PBs were used for day self-drive charter, and I guess the operators felt that the engine was pretty well grockle-proof.

Send me a PM with picture of your boat etc andrewpmcewen@gmail.com if I can get any further info to you I will.

Best

Andrew
 
The thing with the holes looking somewhat like an overlarge pepper pot top, is supposed to glow when the heater plugs have been on long enough.

The keys 2 position , one of them would enable a non heated start for when the engine is hot , the other when using the preheaters.

Surprised the key is removed as usually it controls any gauges, indeed when removed the knowledge the belt is still on driving the water pumps is removed.

A good voltmeter and continuity tester to check power to the glow plugs, and that they work, along with direct application of power to the plugs. just check if they are series or parallel wired as early engines had some surprising systems of glow plug control. Personally would think the starter motor will suffer more for the lack of glow plugs, than the recharging of the battery after the start.

this might be useful

http://www.170v.de/yabbfiles/Attachments/Preheating.pdf

and

https://mercedessource.com/store/om-636-diesel-engine-monark-fast-glow-conversion-kit


again I concur re air filter, more help as an induction noise reduction device than removal of dirt.

The om636 was a burst proof engine fitted in many cars and industrial uses.


key like this one http://www.ebay.co.uk/itm/Bosch-Ign...pt=UK_Motorcycle_Parts_13&hash=item20d709af0a ?
 
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