carb adjustment problem

[spyghost]

Hi,

I am having a hard time finding the right adjustment for my carburetor. It is the stock carb of a 4G15A engine - variable venturi piston type carb (single jet).

please take note that i have a new set of spark plugs, air/fuel filters. distributor is in good condition, new oil, just finished right timing. i just had my carb rebuilt (cleaned). all measurements are correct. no leaks in any part, new gaskets, float bowl is correct height. all vacuum hoses are new as well.

di ko lang talaga makapa ang proper adjustment ng main jet saka a/f mixture screws.

I was able to get a good run last week, but after some time, I found my car stumbling hanggang sa mamatay makina. ang hirap iistart ulit. me-crank pero parang walang pumapasok na mixture sa cylinders. ang tunog nya e starter motor lang. parang hindi tumutuloy ang takbo. hanggang sa umandar din. at this point during idling, untiunti bumamaba ang rev na kahit WOT ako 1,500 lang ang naaabot.

another incident is while i am running (rekta na), e kakadyot ang andar. kelangan ko bombahin ang accelerator para tumaas ang rev. same case, up to 1500 lang ang WOT. pag natsambahan ng bomba, e aandar naman ng ayos ang makina.

i am worrying kasi, baka pag kasama ko ang baby ko e magkaproblema ako, kawawa naman ang bata.

i am looking at three possible things:
- lack of gas
- lack of air
- lack of a/f mixture

ano kaya itong na-experience ko na ito? nakakabaliw. i know there is a solution, kasi bago ako magbaklas e maayos naman. i just need guidance in the main jet screw and a/f mixture screw.

[youngrider]

SPARK - Ok/?

VACUMM- OK/?

CARBURETOR-OK/?

FUEL PUMP-?????

[spyghost]

SPARK - Ok/?

VACUMM- OK/?

CARBURETOR-OK/?

FUEL PUMP-?????

fuel pump is ok... i tried cranking with the hose detached. dami gas na lumalabas.

[youngrider]

Have you dismantled your carburetor, I knew someone who unknowingly lost a small 'bolitas' that somehow regulate fuel flow in his nissan sentra carburetor.

Actually yung mekaniko ang nakawala, hayun katakot-takot na problema ang resulta. Hanggang ngayon palyado pa rin, kung saang galing na bolitas ang ipinalit wala raw makitang original.

Anyway double check for spark, vacumm leaks, and carburation. This link may help you: http://www.aa1car.com/library/carburetor.htm

[spyghost]

yes, i dismantled my carburetor, but i didn't loose any part down to the smallest part.

the bulitas in my carb is actually for the accelerator pump, which functions only when you suddenly press the accelerator pedal or sudden WOT.

how can i determine if it is a vacuum leak? i also changed all the vacuum hoses. i used the replacement hoses. those 1/4" sold in auto supplies.

[reym]

Hi,

Can you simulate the hardstarting condition? If the car starts very hard then on the time it is is hard starting, disassemble the the carb or try draining it to see if there is some fuel in the carb. If there is not enough fuel in in, remove the line that is going to the carb and crank the engine again, if there is fuel, your carb's filter is clogged , if not, your fuel filter might be the culprit.

I had an intermittent carb blockage before, I solved it by 1. cleaning the tank,
replacing the filter and overhauling the carb.
turns out that a portion of the tank was chipped and is blocking the line.