74 3.0 CS - No Start Issue

Squirters ( accelerator pumps) must work for smooth acceleration or else it stumbles off idle and then picks up again.

Sometimes they stick and don't travel the entire bore even though from the outside the arm is travelling normal.

Especially from extended sitting.
 
Removed and cleaned the accelerator pump piston and the bore. Put it back in and still no squirt, regardless of how far the accelerator pump piston is depressed. There is fuel in the accelerator pump though.
 
Take the pump out and try blasting carb cleaner into the hole in the bore where it sends the fuel out the nozzle to see if there is blockage or if cleaner comes out. What is the condition of the skirt seal around the pump? When you press down on it does fuel leak past the seal? the nozzle can be removed for cleaning, check it for blockage and blast cleaner back towards the pump, careful not to drop it down the throat or break it when removing/replacing.

GTSilver944 said:
Removed and cleaned the accelerator pump piston and the bore. Put it back in and still no squirt, regardless of how far the accelerator pump piston is depressed. There is fuel in the accelerator pump though.
Click to expand...
 
Try to determine if there are any deposits in the bore. Especially for about 1" down. That's where all the pump action takes place. I've used fine wet sandpaper to smooth it up. Easy does it. Just like honing cylinders.

The top of the accelerator piston should be at or above the bore. This is important. If the arm is loose, meaning does nothing for half the travel then you're going to get 1/2 or less and never fill the bore with fuel.

Find a peice of fuel hose that fits in the bore. Blow on it.You're checking the check valve operation at the bottom without taking off the next lower carb section. Fuel in ( sucked up by the piston), check valve- to hold it in, pump, fuel out the squirter.
 
You guys are great.

Bore is clean. Looks like the nozzle is clogged. How do I remove it - I'm not seeing a section for that in the manual?
 
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hope this can help

if you start cleaning things, you may realize that there are always another tiny hole, nozzle or whatever you would like to clean, you will never now if the problem was there or in the next sub-level, i had a similar issue and after two years of hesitation, and with the help of jerry and steve, i tore them down until all washers, bolts, and nuts were free to be cleaned individually

it was not so difficult provided you take pictures of the process and notes of the dissasembly, together with a couple of carb manuals available on the technical chapter of this site

here it is the link to the general work of dismantling, clean, renew, and reassembly of my two zeniths (includes basic adjustments):
http://e9coupe.com/forum/showthread.php?t=8569&page=2

spare parts (big kit) available at classicgarage in usa

for adjusting and synchronising:
http://e9coupe.com/forum/showthread.php?t=8944

hope it hepls

regards
 
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Scroll down until you get to the accel pump section, it shows the pump and nozzle cleaning procedure:

http://www.sehlin.com/cscoupe/tech/zeniths/bmw1/bmw1.html#004

Basically you have to twist while pulling it out of the venturi - needle nose pliers and something to lever it against the carb body - it's just stuck in there and held by friction. Consider putting something underneath like paper to catch it from going in if you drop it.
 
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The nozzle was occluded and is now clean. However, if I try to spray carb cleaner through the hole where the nozzle mounts or through the hole in the bore, nothing goes through. I'll order the kit and take it apart to clean. But I've run out of time as I'll be away from the car until December. Oh well.

Thanks for the links. And that's a great thread with very helpful pictures!
 
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