by Skorpion » Fri Mar 05, 2010 12:30 pm
Hi,
When I had my ETZ 250-300, I found that the setting of the ignition and carburation was critical for a smooth engine on a closed throttle,
First with a dwell meter set the points Dwell Angle to 132-136 degrees.
Then adjust the ignition timing to 2.5-3.0 mm BTDC nearer 2.5 the better as when the heel on the contact breaker wears it will advance the timing.
For the carburetter with the three screws holding on the float chamber, (can't remember number maybe, 30n 2.5)
Check that when you blip the throttle the revs come back down immediately, if they come down slowly screw the air screw in, 1/4 turn increments to enrich the mixture while adjusting the slide stop screw to give a tick over of about 1000 RPM this may take some time.
Ignore that the manual says air screw 1.5 turns out, all carbs wear.
Fuel level in the float chamber needs checking, in the works manual it shows using a spare float chamber with a hole in the side and a perspex window glued over, this is the only way to check for correct fuel level.
With patience you should now have no lurching
The problem with the 250 MZs are that they will run with widely varying settings but roughly,
If it kicks back when starting it usually means ignition is too far advanced.
Hope this helps
Skorpion
14 years on 1988 ETZ 250-300 and NO lurching.
Sorry I sold it now.
Last edited by
Skorpion on Sat Mar 06, 2010 4:27 am, edited 3 times in total.