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Engine running rough at certain revs

Posted: Fri Jan 19, 2007 6:33 pm
by Nev
Lately my 1.3L carb has been running a little rough. I can feel a high frequency vibration through the car when tapping the accelerator quickly from idle and backing off and also at 1600rpm and 3000-3600rpm. It happens in the same positions when stopped in neutral as well. Im pretty sure its not driveline related because of this and it seems its coming from the engine as its with certain revs. It doesnt bog down at all in the regions either so dont think its missing. Also noticed when reving it the cars puffing a bit of black smoke whereas its normal for this engine to be burning a bit of oil if anything...not fuel.

Anyone have any ideas or suggestions to check? Thanks John.

Re: Engine running rough at certain revs

Posted: Fri Jan 19, 2007 7:44 pm
by JrZook
Nev wrote:Lately my 1.3L carb has been running a little rough. I can feel a high frequency vibration through the car when tapping the accelerator quickly from idle and backing off and also at 1600rpm and 3000-3600rpm. It happens in the same positions when stopped in neutral as well. Im pretty sure its not driveline related because of this and it seems its coming from the engine as its with certain revs. It doesnt bog down at all in the regions either so dont think its missing. Also noticed when reving it the cars puffing a bit of black smoke whereas its normal for this engine to be burning a bit of oil if anything...not fuel.

Anyone have any ideas or suggestions to check? Thanks John.
The black smoke could probabily be from a stuck on choke or blocked air filter. That the hat off the carb when then engine is warmed up and see if the choke flap is fully open.
The vibration could be from the engine running rough because of the rich condition if the choke flap is not fully open when its hot. Also check your engine mounts or gearbox mount they might be broke and causing the vibrations to travel thru the chassie.
Cheers Dan

Posted: Fri Jan 19, 2007 10:09 pm
by Nev
hmmm...well its got a very new air filter and choke seems to be working well as it still goes on for a cold start and gradually comes off as it warms up as it should. Gearbox was broken which I thought was the problem but now its replaced and its still doing it but it has improved so I thought it must be a separate problem. John.

Posted: Sat Jan 20, 2007 5:45 pm
by Highway-Star
This will sound like a pain, but it worked for me about a week ago.

Check for any disconected 'vacum hoses' around the carby, intake manifold region. Anything missing, and these engines will run rough as guts.