Engine raving but stops

Hi I have just rebuilt my polo engine ... installed new standard bearings and pistons but my problem is when I am starting an engine it takes time to start and when is it has started its just stop on its own to run when I move the foot from accelerator What do you think is the problem. I m just a novice engine builder and thi s was my first project.

Thank you

Perhaps the engine has the throttle stop set too low. Or the throttle position sensor is not reading the correct voltage for the throttle postion so the ECU isn't supplying the correct fuel. Have you looked at any procedures in the factory workshop manual for setting the throttle & sensor?

It could be one, or more, of many things.

Easiest things to check are the vacuum lines/hoses are all in their correct places, and all the electrical connections are in place. They've caught us all out, one time or another.

There could be a mechanical problem, for example the cam' timing being a tooth out - again, easy to do for a beginner.

If it has a distributor, check you have the correct firing order - #2 and 3 are sometimes swapped by accident.

Really, though, even those experienced with that specific engine may not be able to help much because of the lack of information and not knowing how well it's been put together.

Owk thanks I will check issues you have raised