I have this week changed the clutch in my bus. I have 2.0 AC CU Engine which will now not start. The situation is as follows.
1) I have had the engine running since I changed the clutch although the engine will only occasionally (1 in 50 starts) run at elevated RPM.
2) Starter Motor works fine.
3) There is fuel being delivered to the carbs and after some time of unsuccessful starting the plugs are becoming wet which tells me the fuel is getting where it needs to be.
4) There is a spark when you turn the engine over. I have attached a timing gun whilst cranking with the starter and the spark occurs at approximately 8deg BTDC.
5) When the engine does run it is at elevated RPM the timing gun shows a very high advance at around 45deg BTDC. To get it to run I have to advance the dizzy considerably and even then it might run 1 in 50 starts.
6) I have checked the timing mark actually does equate to TDC on cylinder no 1 with the dizzy firing no 1.
7) No major air leaks.
8 ) Power to the coil is 11.4V and is the same at all the connections to the carbs.
9) The carb solenoids are working.
10) Done a general check of all electrical connections.
11) When I crank it over there is not a pop, whistle or misfire at all.
12) I am going mad please help me.
If you've got the standard electronic ignition fitted and all the vac pipes connected the timing should be at 4-6' ATDC. If you're getting a spark at 8' BTDC the ignition is too far advanced. The vac off the air box retards the ignition for starting & idling. If it's too far advanced & the engine's idle is too high this vac signal is "lost" and the vac signal from the carb kicks in and advances the ignition making matters worse.
2ltr Aircooled CU with twin Solex's & originally a 009 dizzie, but now back to standard.
Thanks. I forgot to mention that the 8BTDC is with the vac pipes off and my finger over the vac pipe connected to the manifold behind the airbox.
Is this correct? I undertood that when you re-connect the vac pipes the timinmg should move from 8BTDC to 4-5ATDC ? ? ?
With both vac pipes blanked / blocked the timing should be as you've set it at 8' BTDC. You need to blank the left hand carb connection, not just the one on the balance pipe on the bulkhead. The engine should run but the ignition will only advance to about 30' BTDC on the mechanical advance. How was the engine running before the clutch change?
2ltr Aircooled CU with twin Solex's & originally a 009 dizzie, but now back to standard.
Make sure when you re-connect the vac pipes that you connect them to the correct sides of the vac can. Putting them on the wrong sides might give the symptoms you're getting.
2ltr Aircooled CU with twin Solex's & originally a 009 dizzie, but now back to standard.
