Weber- Hard Starting

[3crows]

I replaced the Hitachi carb with a Weber on my '86' Soob several months ago and in general it runs fine except now it takes more cranking to start. I put an inline fuel filter just before the carb and noticed that it doesn't fill completely when the car is running and is even less full before I try to start it. Is that normal? The butterflies are closed so I guess the automatic choke is working. I'm wondering if this is a sign that the fuel pump is getting weak. Timing is set at 8 or 10 degrees. When I first start, it idles at about 400 RPMs and won't stay at 7 or 800 until it warms up. I had to put an extra spring on the throttle to make it idle down after acceleration. I can live with the idle situation but the excess cranking on the starter doesn't seem right. Any thoughts?

[naru]

Forget about the pump and filter.

VERY unusual for them to be related to STARTING problems.

 

You need to

1 Adjust the choke

2 Adjust the choke unloader

3 Adjust the fast idle speed

[3crows]

When I adjust the idle speed to 800 RPMs after warm up it starts at 400 RPM when cold until it gets warm again. If I adjust it to 800 RPMs at start up it idles at 1500 RPMs after it warms up. If the butterflies are closed at start up, isn't that as 'Choked' as you can get?  I don't think it's starting rich. What am I missing?

[naru]

1.The choke needs to be closed w/the correct amount of spring tension.

2.The choke unloader opens the choke about 1/8 inch(check specs) with engine cranking vacuum.

Choke fully closed is too much choke once the engine turns

3 The fast idle adjustment is completetly seperate from the curb idle adjustment.

Set curb idle to 800 warm

Set the fast idle to about 1700 w/cold

 

There is a photo of the fast idle screw here http://datsun1200.com/modules/mediawiki/index.php?title=DGV_connections_and_adjustments

Or,#65 here http://www.carburetion.com/diags/3236DGAVDiaginfo.asp

Edited April 9, 2017 by naru

[3crows]

OK, I'll try that. Thanks.

[wagons]

Check ignition timing. That will make it idle bad. Also webers dont need a lot of fuel

[3crows]

Found the high speed idle screw and turned it in and then out. All it does is move the butterflies but doesn't change the idle speed. I cupped my hand over the carb throats which on every other carb that I've worked with would suck your hand down and increase the RPMs. Didn't suck my hand at all. No noticeable vacuum. Instead it was about to stall. Once it was warmed up I set the idle speed at 800RPMs and set the butterflies at just full open. I'm waiting for the engine to cool down to see how much the butterflies close. I don't understand the lack of vacuum at idle. I also disconnected the fuel return line since the web page you sent me said that this model Weber doesn't need it.

Well, it's been many hours now and the butterflies are mostly closed; maybe 85%.

[l75eya]

If you put your hand over the carburetor barrels and it sucks your hand down the rpms will never increase and the car will stall, because you have essentially blocked all airflow into the motor.

Your timing should be at about 15* with the Weber. Is this a Weber with electric choke? Did you hook up the blue wire to it?

You should still make sure to fully depress the accelerator to the floor once before starting the engine to set the choke. The filter not filling is fine, it doesn't use much fuel pressure.

[3crows]

It has an elect. choke and it works. I'll try backing the timing off and see how that works.

Thanks.