Hello all,
OK here's the scenario. Parilla IAME 100cc engine with Tilly HL series carb. Should, with gearings reach 14,600- 14,800 with no probs. Racing yesterday and nightmare!!!
Had a big off, lots of stone and stuff in chain area etc. Re built back end. Stripped carb and to be fair looked hard and couldn't see any bits or stuff inside or after removing jets, in there either. Took decision not to replace membranes as they all seemed OK and worked great before off. It was the final to come so didn't want to disturb things anymore than necessary. Used loads of carb cleaner and screwed back together firmly
All back together and settings as before - started her up.
Ticked over great, thought we are OK here. Then the engine picked up all on its own and raced up to 12,000 plus on its own. Shut it down and thought whats going on. Checked the settings, breather pipe, fuel supply etc and started her again, same thing, off it went racing up to high revs.
Took out low speed jet and looked at it. all seemd OK, quick wipe and spray with carb cleaner and back in to setting. Started OK and ticked over, thought problems solved.
Final. Drove out of pits, no pick up at all. Just nothing there at all. It was as if no fuel was getting in or too much as well. Just nothing. No coughing or spluttering just no ooomph. Adjusted carb on the move, nothing made any difference. Had to pull off after two laps of fuffing around.
But here's the thing. Put it back on stand and started her up, started first time, tick over OK. Applied brake for resistance and she picked up straight away. No stutter at all.
Now OK, two things here. Perhaps in hind sight, should have left well alone before final and just accepted it as it was. Perhaps should have changed membranes, BUT and here is the question for all. Why did it race away on the stand and why did it not pull away normally on the track and why did it preform OK again on the stand again afterwards???
I know the Tilly or so I thought, but this thing has me stumped. Just want to learn what we did wrong and also I guess, what was going on inside the carb?
Cheers.
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Tilly problems - loss of pick after rebuild?????? by 'quercus' << You are here!
