4G15 SOHC Carby, Fuel Regulator?

A

anonymous4g15

New Member
Hi all been searching and searching for a workshop manual for the 4G15 SOHC carby (95 Lancer cc) with no success.

The carby has recently been upgraded and am trying to figure out if there is a stock Fuel pressure regulator that i can exchange out for an aftermarket adjustable one. The running is still rough, When you put your foot flat it will just kill the engine.

Hoping that adding filters to the new carbys will add a bit more restriction which the carb manual said it needed or it can run rough.


Any help/information will be greatly appreciated thanks.
 
nope there is no regulator. these things run a mechanical fuel pump you find it on the back of the motor timing belt side. i've got some manuals hosted and i'm pre sure theres the 1.5l carby buried in them somewhere. server is dwon atm though will have it back up shortly
 
Not sure if these used the same trick. The old 4g5X engines used to run a mechanical pump also.
Fuel pressure was set by the thin black spacer between the fuel pump mount & where it mounted to. Having the effect of differing the point where the pump was operated on its lever.

That being said. I'd highly doubt you have a fuel pressure problem.
Few things about carbies:
-I've never seen one require more than about 4PSI, that is about the max the needle valve will handle.
-the float bowl will hold some fuel, think of it like a reservoir.

Even if you give it full throttle, it shouldn't die straight away from fuel starvation, as the float bowl will take a short time to empty out.
If you are finding the car die's after a short amount of acceleration, then you may indeed have a fuel supply issue. But, not directly a pressure issue, more flow.

What carb have you put on there? got some details?

Provided a mechanical fuel pump is in good working shape, I'd highly doubt it will be a restricting factor.
-For reference. I've had a standard mechanical fuel pump feeding two side draught carbs on a 2lt. Never had a fuel issue - even when holding it on the rev limiter sideways :thumbup:
 
Fitted are 4x 32mm Mikuni BS32SS CV carbs.

It needs full choke to start and idle even after 10 or so minutes of running you cant let the choke off or it will die. We are yet to fit air filters on there so its running free flow atm.
if i let off choke you can only just keep it alive by reeving the engine but its almost like fighting a losing battle
 
What were they off previously?
Have you tuned them at all?

The difference made from an air filter is next to nothing. If it does make a difference, the filter needs to be replaced.
 
They are previously off Suzuki GS 650.
Tuning wise the way they are designed they are meant to be almost bolt on and go after idle adjust.
 
To an extent they should.

Although I would imagine the idle mixture would be slightly different, not so much the desired idle mixture, more to do with how the carbs react with the different engine.
I'm not overly familiar with those carb's. Do they have an idle mixture adjustment?
(Might be worth your while buying an exhaust gas analyser too)

Also, did you make the manifold your self? If so, where has the vacuum advance for the dizzy been connected?
-Maybe a picture might be easier?
 
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