Volvopenta 250 4cyl bad starting from cold but will start all day long once its been run.?

Question

everything is new!!! everything is set to the manual spec,on turning the key first time from cold it will fire up albeit on a couple of cylinders,if im really quick and feather the throttle it bursts into life and runs perfect and will start all day long,if i dont catch it in the 3-5 seconds that it will run for then no amount of turning it over will get even a splutter.the two back plugs will be drowned,the front two dry,put the plugs on the cooker for a few minutes and it will start.iv noticed that the back 2 are always black&sooty the front 2 nice light brown.Its a twin carb set up and both carbs have been totaly overhauled and are set exactly the same as far as mixture screws etc,and to the book settings.This engine does not use a single drop of oil and has perfect compression on all 4 cyl.Its as though its overfueling on the back 2 cylinders but i cant fathom why,it has no manual choke,instead its some kind of vacuum set up that chokes it,i cant understand why 2 wet&2dry, HELP!!!

Answer 1

Although you say the carbs have been set up the same, are they balanced correctly? and is the cold start working  on the front carb?

Come to think of it - is the cold start on the rear carb actually switching off?

A few things to consider.

Answer 2

you should have bought and outboard

Answer 3

You answered your question. The back two cylinders are fouling out due to excess fuel. Although they may be set the same the carbs are not syncronized. The carbs must be set to work together not just set the same. Either sync them together your self or have a mechanic do it for you. I had a problem similiar to this on a motorcycle once and that was the problem. Hope this helps