soldiersteve Posted May 17, 2015 Share Posted May 17, 2015 I have a Commer Q2 with a Solex 40 FAI carb which has been standing for a few months. When I start it up either with or without choke it starts and runs fine. However it will not drive without the choke full on. If the choke is off then as soon as I open the throttle the engine dies. If the choke is full on then it will drive but is quite rough. I have been told that this is due to too much air and have tried to adjust the mixture screw but to no avail. However someone else has suggested that it may be a fuel starvation problem. Any suggestions would be gratefully received. Quote Link to comment Share on other sites More sharing options...
Nick Johns Posted May 17, 2015 Share Posted May 17, 2015 (edited) I have a Commer Q2 with a Solex 40 FAI carb which has been standing for a few months. When I start it up either with or without choke it starts and runs fine. However it will not drive without the choke full on. If the choke is off then as soon as I open the throttle the engine dies. If the choke is full on then it will drive but is quite rough. I have been told that this is due to too much air and have tried to adjust the mixture screw but to no avail. However someone else has suggested that it may be a fuel starvation problem. Any suggestions would be gratefully received. Probably a result of todays rubbish petrol that actually has a use by date, it deteriorates after a few months and leaves residue that blocks the carb jets and can eat through fuel pump diaphrams and rubber pipes. Clean the carb out, drain the old stale fuel and put in fresh Edited May 17, 2015 by Nick Johns Quote Link to comment Share on other sites More sharing options...
fv1609 Posted May 17, 2015 Share Posted May 17, 2015 Are you ok for carb diagrams etc? I notice the Q2 manual of 1950 was heavily amended in 1951. Quote Link to comment Share on other sites More sharing options...
Diana and Jackie Posted May 17, 2015 Share Posted May 17, 2015 ASDA fuel, which is usually the cheapest is also the cr****iest and will not burn in a No2 stove. It also stinks to hell. Maybe for a few pence it is worthwhile avoiding it? Diana Probably a result of todays rubbish petrol that actually has a use by date, it deteriorates after a few months and leaves residue that blocks the carb jets and can eat through fuel pump diaphrams and rubber pipes. Clean the carb out, drain the old stale fuel and put in fresh Quote Link to comment Share on other sites More sharing options...
paulbrook Posted May 18, 2015 Share Posted May 18, 2015 (edited) The fuel would have to be seriously rotten to cause the symptoms described. Take the union off the carb and pump some fuel into a container. If it is the colour of tea (without the milk) and if it stinks (a sickly smell) then it may be off, but even then the truck would just pop and bang and would probably run better lean (ie no choke) than rich (choke on). Remember that this was an engine that would run on pool petrol. That said the best approach has already been mentioned, and that is to strip it all and clean I out; in particula look for condensation in the bottom of the float chamber - a mere droplet of water would cause the symptoms described. For good measure undo the feed from the tank to the pump, stick an airline with a few PSI pressure on it and blow that al back into the tank too. Edited May 18, 2015 by paulbrook Quote Link to comment Share on other sites More sharing options...
soldiersteve Posted May 27, 2015 Author Share Posted May 27, 2015 Hi all Thanks for your comments. In the end I took out the main jet and gave it a quick clean up after which it has been performing a lot better. Quote Link to comment Share on other sites More sharing options...
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