Thread: Discussion Model Diesel Engines
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Old Nov 26, 2012, 08:42 AM
brokenenglish is offline
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Sticks, Tissue & old Diesels
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France, Centre, Amboise
Joined Nov 2011
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Hi, Obviously, the diameter of the holes in the venturi should correspond to the spraybar diameter, plus a very slight clearance, i.e. the spraybar should be a "good fit" in the holes. If it can be waggled about, then it's probably undersize and may well be the spraybar from a smaller engine... This would mean air leaking into the venturi + excess venturi throat area due to the smaller spraybar diameter, which would give fuel draw problems such as you describe. If this is the case, you may have a spare NVA that is a better fit, somewhere in a box of bits. If not, find some fuel tubing that can just be pushed onto the spraybar (an airtight fit but not too tight). Cut two very thin slices of this tubing and use them as washers. Maybe my previous remark about fibre washers wasn't clear. I'm pretty sure your engine shouldn't have them, but they are a good "quick fix" if a spraybar is slightly undersize.
Basically, you just need to carefully examine the whole carburettor area, and make sure that the air being sucked into the crankshaft has to flow down the venturi, and can't leak in from anywhere else!
I don't possess any ME engines, but I think they have a separate carburettor venturi. Does it screw in? and if so, is it a firm airtight fit?
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