Hello all.

After changing the engine chain soon a new problem appeared. The car starts and runs nicely but as soon as the engine gets worm following issue appears: Most of the time I try to accelerate with 2-5 gear selected, the car starts jumping. When I take my foot off the accelerator, it calms down. It never happens when accelerating with first gear and when engine cold. Any ideas?

Felly is 1.3 and carb version. Upper engine mounting seems a bit tired, can this is cause such a thing?

Thanks buddys and sorry for my poor language as English is not my native language.

Yes, a worn engine mount could make the car judder under acceleration. Is it worse if you snap the throttle open than when you squeeze it open gently?

Also, are you certain the camshaft and ignition timing are correct?

Yes, it really is worse when I hit the throttle hard.

About the ignition timing I am not really certain, because I set it myself, just turned the distributor and listened engine and left it at the point engine ran best.

I'm fairly sure it's the engine mount that's causing the judder.

Your ignition timing method is the best I've found, subject to you having a good ear.

I think it's still worth not ruling out ignition timing, given it's just been adjusted.

It's possible, but if you can hear the engine revs changing as you swing the dissie, you're unlikely to get it wrong that way, as long as the cam timing is right (presumes dissie is run off cam, like better than half the other OHV engines I have worked on).

i did that once and i got the spark too advance due to the fact that i set it with the engine on idle with no load, and afet doing this i got a bunny hop and some noise in the engine, if your getting noice like a pop it means that you too set the spark too advanced.

Also once a spark plug on a cilinder got damaged or dirty and did the same thing, take out the spark plug clean them out with carb cleaner, tune the gap to all the spark plugs and check if they give adecuated spark, if so, bolt them on.

also a HT cable damaged could also give you this problem...

at any rate, what you described to me is a cilinder or various cilinders producing knockback or bad combustion. its not noticeable on idle with no load, but a soon as you put some load on the engine you feel it, quite a lot.

if you want to reset the dizzie i recommend with a timing gun and set it a little ofset to advance or a vacuum atached to the plenum, if the sparks are ok, just accelerate the engine to 2000rpm and check vacuum reading, then take it to idle and set the dizzie until you get the same vacuum reading at idle than on 2000rpm, to me, those two are the best way to set your ignition timing.

let me know if this helps, i've encounter all those problems and what i described worked for me, no my car runs like a charm with no noise coming from the engine (no valve sound, explosion sound, induction sound, nothing, it feels like walking on the air)