Asciidv Posted March 13, 2015 Share Posted March 13, 2015 I have a solex 40 NNIP/3 carburetter for a B80. This differs from the normal NNIP as it has an automatic choke rather than a manual choke. This is the picture of the cold start chamber between the two accelarator pumps. The lever arm which acts on the central pin of the diaphragm is operated by a linkage which goes to the choke butterfly. The arm can only seem to pull the pin forwards into the body of the carburettor but as on the other side of the diaphragm ther is a spring pushing the pin forwards too I cannot see how it ever moves from this fully forward position. So just how does it work? Could I have mis-assembled somthing when putting it all back together? Does anyone have a manual showing this variant of the carburettor? Thanks for any possible advice, Barry. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 13, 2015 Share Posted March 13, 2015 Quote Link to comment Share on other sites More sharing options...
Asciidv Posted March 13, 2015 Author Share Posted March 13, 2015 Thanks Clive, really useful! I will set up my carburettor like this in the morning and bolt it back on in the afternoon. Hopefully I will be back on the road on Sunday.:-) Barry. Quote Link to comment Share on other sites More sharing options...
David Herbert Posted March 13, 2015 Share Posted March 13, 2015 So the Bi metal strip on the manifold aided by the spring behind the vacuum diaphram puts the choke on. As the engine starts the vacuum reduces the amount of choke by pulling the diaphram against the spring and as the engine warms up the Bi metal strip uncoils and pulls the choke right off. Basicly the same set up was used on the American cars that I played with years ago. When I got them they had always been messed with by people who didn't understand how they worked but they could always be reset and if done right you hardly knew that you had a cold engine. David Quote Link to comment Share on other sites More sharing options...
fv1609 Posted March 14, 2015 Share Posted March 14, 2015 Yes hope that helps I couldn't find reference to it in an EMER. That was taken from the Rolls Royce Workshop Manual TSD702. Quote Link to comment Share on other sites More sharing options...
Asciidv Posted March 14, 2015 Author Share Posted March 14, 2015 I had completely mis-understood the operation of the cold start chamber. I had thought that it was the linkage from the thermostat which was enrichening the mixture through the cold start chamber, rather than the cold start chamber modifiying the position of the choke (strangler) butterfly. This picture shows the access point on the carburettor for the injection of the 10psi of air to test the cold operation. Here we see the air gun conencted to this point. I simply used a samller rubber (Hellermann) sleeve over the nozzle of the gun to make an air tight connection. The operation of the cold start linkage could now be adjusted according to the manual. Incidentally does anyone have an ORIGINAL copy of the TSD702 Rolls engine manual that they might like to sell to me? Barry. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.