New G15 poor running
Posted: Mon Apr 25, 2005 4:11 pm
Hi Stuart
Unfortunately I am not experienced with any form of electronic ignition, I presume you meant ignition not injection. However, a couple of things to check:
Is the fuel relatively new? Modern fuels do go off quite quickly.
Are the plugs good and of the correct grade?
Is it timed correctly? Most Atlas engines have now been rebuilt using flat top Commando pistons instead of the original dished atlas items. This requires timing change from 32 deg to 28 deg BTDC.
Are carb jets blocked? Again I have heard that modern fuels can gum up the jets quite quickly.
The smoking could be caused by wet sumping or an inlet valve with no stem oil seal or a worn one. There are differing views on whether wet sumping is acceptable or bad for the engine. But I've always found that the pump soons scavenges the excess oil and doesn't blow any seals providing it's left idling for around 5 mins. To check for wet sumping: Run engine for 10 mins then stop and put engine onto compression, then drain oil from crankcase plug for 2 hrs. Note that it is normal for the crankcase to hold around a pint, and the timing case between 1/2 and 1 pint. Rremove drip tray from under crankcase then using a clean tray, see how much oil drains through engine over a period of 24 hrs. If more than approx 150cc, the pump would benefit from lapping in which is an easy straightforward job which I can explain later. Use of straight 50, or 40 oil also helps prevent wet sumping.
My starting procedure on all my P11s is: Use no choke (haven't got them fitted). Flood carbs, open throttle half way for 30 secs. Turn on ignition, ease kickstart onto compression, open throttle very slightly, give mighty kick and they usually start second or third kick, unless people watching then it can be embarassing but not as bad as many Gold star owners I've watched.
Anyway, good luck.
Tim Roberts
Unfortunately I am not experienced with any form of electronic ignition, I presume you meant ignition not injection. However, a couple of things to check:
Is the fuel relatively new? Modern fuels do go off quite quickly.
Are the plugs good and of the correct grade?
Is it timed correctly? Most Atlas engines have now been rebuilt using flat top Commando pistons instead of the original dished atlas items. This requires timing change from 32 deg to 28 deg BTDC.
Are carb jets blocked? Again I have heard that modern fuels can gum up the jets quite quickly.
The smoking could be caused by wet sumping or an inlet valve with no stem oil seal or a worn one. There are differing views on whether wet sumping is acceptable or bad for the engine. But I've always found that the pump soons scavenges the excess oil and doesn't blow any seals providing it's left idling for around 5 mins. To check for wet sumping: Run engine for 10 mins then stop and put engine onto compression, then drain oil from crankcase plug for 2 hrs. Note that it is normal for the crankcase to hold around a pint, and the timing case between 1/2 and 1 pint. Rremove drip tray from under crankcase then using a clean tray, see how much oil drains through engine over a period of 24 hrs. If more than approx 150cc, the pump would benefit from lapping in which is an easy straightforward job which I can explain later. Use of straight 50, or 40 oil also helps prevent wet sumping.
My starting procedure on all my P11s is: Use no choke (haven't got them fitted). Flood carbs, open throttle half way for 30 secs. Turn on ignition, ease kickstart onto compression, open throttle very slightly, give mighty kick and they usually start second or third kick, unless people watching then it can be embarassing but not as bad as many Gold star owners I've watched.
Anyway, good luck.
Tim Roberts