So I have a Maruti Esteem engine with a dual carburetor on an engine dyno and everything was already installed when I joined this lab. We seem to have a problem when trying to fire the engine. 1st and 2nd cylinder are not combusting at low loads and 3rd and 4th are. I know this by looking at the temperature readings at individual cylinders(have installed individual temperature probes in every runner in the exhaust manifold, lambda sensors are not available at the moment).

When running the engine at high loads, all the cylinders are firing (again, I know this by checking the temperatures at the exhaust manifold). I am confused on why certain cylinders in a carbed engine would not run at low loads and then would run at high loads?

P.S. I am a newbie in carburetors and this might be my chance to learn. I can post pictures of the setup tomorrow.

Any help would be deeply appreciated.

EDIT: Here are the pictures

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  • Do we assume 4 cylinder engine, with two carburetors? Can we see an image of the intake manifold? How do you know the carburetors have been balanced and synch'ed to match each other? Here's a reference... And here's the job with a home made manometer...
    – zipzit
    May 30 '16 at 16:09
  • Yes it is a 4 cylinder engine with two carburettors. Just added the pictures. Thank you for your reply! Also, I will take a look at the carb syncing methods.
    – Vish_evo
    May 31 '16 at 4:18
  • Can you tell us the temperatures each cylinder is running at? I want to understand if you have a lean or rich condition on Cylinders 1 and 2
    – Zaid
    May 31 '16 at 10:29
  • We were running at 2000RPM and the temperature of 1st and 2nd were around 150ish deg C and 3rd and 4th were 540 deg C.
    – Vish_evo
    May 31 '16 at 11:19
  • What's the condition of the plugs in #1 and #2? Are they damp, from unburned fuel flooding the cylinders? Jun 1 '16 at 6:37

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