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phil
United Kingdom
149 Posts |
 Posted - 14/10/2007 : 15:31:55
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I have just got my PB running but I am having trouble with the OM carbs. There is petrol pouring out at an alarming rate. I removed the choke assembly and inspected the seals and found that they were perished rubber!!! (These carbs were 'professionally' restored at great expense) I have replced them with cork ones soaked in oil but still no joy.
The problem appears to be where the bottom bearing sits (collar with copper washer). does anyone know if the fit should be tight? mine seems to have a gap all the way round and also 'rocks' if touched. The mix nut has me baffled too. my friends tightens up, mine just spins.
It has been assembled as per exploded diagram in Burlems. Any ideas what to look at?
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DSW
Germany
91 Posts |
Posted - 14/10/2007 : 21:32:18
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Phil,
It unfortunately sounds like a strip and rebuild job around the jet to me. There should be no "wobbly" bits on the carb. The jet should slide smoothly up and down as the choke is used. The nut must move along its thread to provide a stop to the jet at the correct position and set the mixture, not just spin.
If the carbs were re-built quite some time ago and left on a shelf, then cork could dry out and allow fuel past, so should be replaced. Full rebuild gasket sets are quite reasonably priced.
David |
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phil
United Kingdom
149 Posts |
Posted - 15/10/2007 : 08:47:48
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Cheers david, it has new seals. the 'wobbly bit' is the whole adjust nut and brass bearing. i cant work out what is supposed to stop the threaded bearing from turning? shall be phoning burlens today.
Thanks you. |
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Peter Green
United Kingdom
1682 Posts |
Posted - 18/10/2007 : 10:37:39
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Phil,
As David says there should be no 'wobbly' bits on the choke assembly when the nut is done up. I have come across this problem a couple of times in the past, both times it was due to a mish mash of parts with the jet assembly.
I have put a couple of pictures onto the 'Document Download' page of this website which I hope will help explain what might be your problem. If you look at the picture 'Jet Holder' you will see that there are two different types of sleeve that the jet fits into, the bottom halves are different lengths and so are the top halves BUT the two different types are the same total length. What I have found in the past is that if the bottom of the jet holder on the left of the picture is fitted with the top of the assembly on the right you will not be able to tighten the jet up sufficiently to stop it 'wobbling'. The jet securing nut must be able to tighten these two parts together in the carburetter body so there is no movement.
There are also two different types of jet securing nuts and using the wrong one can also stop the jet sleeve from tightening correctly. If you look at picture 'Jet holder/2' you will see the difference. The top lip of the lower half of the jet sleeve fits into a recess in the jet securing nut on the assembly on the left of the picture and sits on top of the nut on the assembly on the assembly on the right of the picture. If the nut on the left hand assembly is used with the assembly on the right of the picture there is also the possibility that it will not tighten up tight enough to stop the jet assembly moving.
I hope the above information is of some help, please let us know if this is in fact your problem.
Peter.
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Edited by - Peter Green on 18/10/2007 12:42:15 |
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