laurel c130 carburetor (Read 100 times)

[boogiez]

i really have tried understanding the principles of my laurel c130 two barrel carburetor coz it has numerous problems. Someone assist me in fixing this problems:-.
- My engine doesnt start unless i pour/spray some fuel directly in the carburetor ...
- When the engine starts it doesnt idle, and when i step on the gas it runs for some few minutes then dies.
Ive tried adjusting the mixture screws- nuthing.
- The carb initially had jet sizes - 160 and 115, but changed the 160 jet to 130.
-Umm this may not be related to the carb but the engine misses, the last cylinder aint firing, ive tried swapping lead wires and spark plugs but nuthing... someone assist me.

[Al Ramone]

any reason you've changed the jet?

is the float bowl filling up?

there is a fuel cut off device on the carb which stops fuel when the ignition is turned off. it'll have a single wire going to it. if this isn't connected, or live when the ignition is turned on, then it will not run at idle.

[boogiez]

A mechanic told me the jet size differences are too far apart i.e 160 and 115... so he recommended me to try 130 and 115. and yeah the fuel cuttoff device has its wire connected well.. ive checked it.
Any ideas why it doesnt start by itself instead needs someone to pour some fuel in the bowl?
and wen it starts its it stays on for some seconds and then dies ...

[Al Ramone]

i wonder why your mechanic thinks he knows better then the guys who built the car....?



it sounds like there's a few issues with the car. answer these questions and maybe we can help.

has the fuel tank got fuel in it?

is the fuel pump working?

is fuel getting to the carb via the fuel pipes?

is the float bowl in the carb filling up?

[boogiez]

Hey al, the fuel system is fyn. The pump, the pipes, everything is working just fyn. Yesterday i checked the float bowl turns out the linkage that cuts off the fuel had jammed. but i fixed it and its now filling up to the level.
Also after revving up the car for some mins, the car now starts by itself. I think the carb is now working fyn.... But i think the jet size has affected the performance of the engine.
Now the only prob left is the last cylinder thats not working.

[pocc]

A cylinder not firing is pretty easy to diagnose if you follow the procedure. All it needs is fuel, compression and a good spark - in the right place .

1. 1st thing is a compression test - if it's not somewhere between 125psi (worn L series - very rare) and 175psi (common if the head was skimmed after a failed head gasket) in an L series engine, there's something amiss. It's worth checking them all down the line while you're at it as any imbalance can mean a failing head gasket!

2. Your mate who thought the jet sizes were too far apart to be right didn't understand the difference between a twin barrel carb and a two stage carb. The Nikki and Hitachi's fitted to old Datsun's and Nissans are two stage carbs - with the jet you've put in you'll run it very rich on full throttle - it'll hunt as the vacuum dies away from running rich and cycle opening the second stage again.

3. Spark in the right place - It's worth picking up an HT indicator to make sure there's HT there. The No.6 lead being the longest HT lead is prone to breaking down - check the resistance of the lead - anymore than 10k ohms - bin it.

Hope this helps a little.