AQ 125 carb plate

[rstinson]

There is a plate under the carb and it has a weird corner on one of the inside corners. It has "front" stamped on it and it wasn't installed that way so I put it towards the front of the engine. Is this correct and what is it? Volvo AQ125 1983 Bayliner
Thanks, Rob

 

[el_pescador]

The plate is supposed to have an arrow as well. If it says "front", the arrow should point towards the front of the engine.

 

[el_pescador]

I havent heard an answer to that question just that is how the engeneers want it. My guess is it creates a turbulance in the manifold to mix the air fuel better but that is just a theory. I am sure it has a purpose let us know if you find out.

http://www.marineengine.com/boat-forum/showthread.php?252089-Carb-Rebuild

 

[rstinson]

thanks for the info, I can buy the turbulence theory. Put it back correctly and gained 25hp, just kidding.
Thanks for the time. Rob

 

[pugetsounder]

I've scratched my head over that plate as well. Nice to have an answer for it.

 

[dennis461]

I think "turbulence" is incorrect.
From what I know of carbs, fuel, and old thinking, IMHO it is to lower the running actual compression ratio.
Not the static testing compression ratio.

It could be Volvo Penta thought the auto engine compression was too high and were afraid of preignition.
There may have also been a import tariff issue for European boats, so lower horsepower was the goal, then the plates became standard.

The curious part I'm still working on is why it has FRONT marked on it,
anyone know if it's the same plate for dual carb setup?