Vintage56
Active Member
@Stevehose thank you for the clarifications.....Do you have a photo of the small hole in each carb to vent the idle mixture screws? There are several "holes" in the top of the carb of various sizes. TY....
Zenith Carbs Massive Flooding
- Thread starter Vintage56
- Start date
Vintage56
Active Member
PERFECT...
Gaskets and hole clearance next....
Gaskets and hole clearance next....
and needle valve cleaning
Vintage56
Active Member
Got it....
Today we found the front carb on the Turkis car in Iran was flooding, upon further investigation we found the float had a tiny hole and the glued joints had an opening in it, thus filling the float with gas and making it heavy enough to get stuck at the bottom.
Tomorrow a replacement float will be installed and hope to remedy the flooding.
Tomorrow a replacement float will be installed and hope to remedy the flooding.
Coast Motor Werk
Member
Kinda skipped to the end here so if I sound like I am repeating someone apologies. The only thing that will cause the symptom you described is the float level. Carbs don't like sitting especially with todays high methanol fuel. If the fuel in the float bowl evaporates it leaves sticky deposits, if this happens repeatedly it can cause the float to stick down. New fuel can loosen but will not remove the deposits. The carbs need to be overhauled. In the future if you know the vehicle is going to be sitting you can close the fuel line off to the carbs and let the engine run off the fuel in the carbs until it dies. This will prevent deposits in the float bowl, pumping the throttle 4-5 times after it dies will drain the accelerator pump well, but in general carbs do not like sitting and Zenith carbs are no exception. If you have them rebuilt be sure it's by someone who genuinely knows them. I have fixed many mistakes made by "carb guys", just ask @HBchris. Good luck!
The owner of the big car museum told once he's currently draining all the fuel from the cars. Not only because of fire risk but mainly due to ethanol content in the current fuel.
Times it was possible to start the car with an old fuel are gone.
I have lost three electric fuel pumps in my E30 due to ethanol negative impact on standard fuel systems including injected cars (D-Jet, K-Jet, LH-Jet and Motronics-equipped).
Times it was possible to start the car with an old fuel are gone.
I have lost three electric fuel pumps in my E30 due to ethanol negative impact on standard fuel systems including injected cars (D-Jet, K-Jet, LH-Jet and Motronics-equipped).
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Vintage56
Active Member
UPDATE TO ALL:
Yesterday I started the E9 and she started right up after installing some of the pieces that came with the carb rebuild kits. Waited for the idle to settle and took her for a ride. No flooding. All good so far, except I now have a slightly higher idle speed (about 1000-1100) and a richer fuel mixture (slight amount of smoke at fully warmed up idle). (Compression is about 180 in all 6 cylinders as I had that checked by my mechanic before I bought the car.) I know I didn't alter anything as I only worked with the top sections of the carbs and didn't reset anything else. Any suggestions?
I am not sure with Zeniths which screws control idle speed and mixture. I don't want to fiddle with stuff until I have a pretty good idea I know what I should be doing. I am not confident to readjust everything since this will be way above my pay-grade. Right now the car starts, idles and runs without surging or stalling. It's just a heavy smell of carbon monoxide and a slightly higher idle speed. So I know I am pretty darn close. I also do not have any hesitation up the RPM range and when coming out of a standstill....But perhaps that's because she's too rich?
Thanks for any input...
Merry Christmas to all.
Yesterday I started the E9 and she started right up after installing some of the pieces that came with the carb rebuild kits. Waited for the idle to settle and took her for a ride. No flooding. All good so far, except I now have a slightly higher idle speed (about 1000-1100) and a richer fuel mixture (slight amount of smoke at fully warmed up idle). (Compression is about 180 in all 6 cylinders as I had that checked by my mechanic before I bought the car.) I know I didn't alter anything as I only worked with the top sections of the carbs and didn't reset anything else. Any suggestions?
I am not sure with Zeniths which screws control idle speed and mixture. I don't want to fiddle with stuff until I have a pretty good idea I know what I should be doing. I am not confident to readjust everything since this will be way above my pay-grade. Right now the car starts, idles and runs without surging or stalling. It's just a heavy smell of carbon monoxide and a slightly higher idle speed. So I know I am pretty darn close. I also do not have any hesitation up the RPM range and when coming out of a standstill....But perhaps that's because she's too rich?
Thanks for any input...
Merry Christmas to all.
Coast Motor Werk
Member
You are a smart to know your "pay grade" many actual mechanics don't. That said, there are many things to verify BEFORE turning a screw on the carbs. The fact you had flooding going on before, I would start by changing the fuel fouled oil.
1Verify your valve lash. I understand 'it ran great before', but this is the best practice to do this.
2Then verify dwell and you have 32deg total timing advance at 3k rpm(vac advance disconnected).
3Fresh and properly gapped spark plugs.
Okay, now you can touch the carbs
Use the "Blue Book" for initial settings. This will get you close, someone here should have it and can send you the pages. I am away from the shop.
The real "trick" is balance, this should be done with air flow syncs. This is generally where the boys & men diverge LOL.
Considering you made it this far, you have the flooding problem corrected, all baseline engine checks done, now it's time to up the pay grade.
1Verify your valve lash. I understand 'it ran great before', but this is the best practice to do this.
2Then verify dwell and you have 32deg total timing advance at 3k rpm(vac advance disconnected).
3Fresh and properly gapped spark plugs.
Okay, now you can touch the carbs
Use the "Blue Book" for initial settings. This will get you close, someone here should have it and can send you the pages. I am away from the shop.
The real "trick" is balance, this should be done with air flow syncs. This is generally where the boys & men diverge LOL.
Considering you made it this far, you have the flooding problem corrected, all baseline engine checks done, now it's time to up the pay grade.
Vintage56
Active Member
Thanks for the feedback, I appreciate the immediate responses and sage advice on this Forum! Thanks all
Merry Christmas.
Merry Christmas.
Coast Motor Werk
Member
Enjoy your holidays, If you need the Blue book info let me know and I will post or send it after I return from camping.
Vintage56
Active Member
Thank you, that would be very helpful. Enjoy camping!
Vintage56
Active Member
Thank you deQuincey! You've been extremely helpful throughout this issue.
you can follow the whole adjustment process here,…
LAN my renewed engine M30B30 Running in process
Howdy. This is the kind of things that i do best, providing useful hands-on documentation for people that love the emotion to have dirty hands and white smiles in their faces while taking care of their e9 coupes or e3 sedans I take the information comming from the blue books, and bring my own...
e9coupe.com
it includes some other issues
About halfway through the Zeniths manual on this site: https://e9coupe.com/tech/zeniths/bmw1/bmw1.html in the 'overhaul' section, there's a warning about replacing the tower with a vent chimney which discharges excess/flooded fuel directly into one of the carburettor chokes - see below
The chimney shows up clearly on this parts image: http://bmwfans.info/parts-catalog/E...aration_system/carburetor_cap_piston_float_2/
When E3s were plentiful, I picked some up to make the change - I read it as a safety matter.
I guess that if there's a serious fuel flood and it's directed down the choke, the effect will be to stop the engine.
The chimney shows up clearly on this parts image: http://bmwfans.info/parts-catalog/E...aration_system/carburetor_cap_piston_float_2/
When E3s were plentiful, I picked some up to make the change - I read it as a safety matter.
I guess that if there's a serious fuel flood and it's directed down the choke, the effect will be to stop the engine.
It looks like that change was from October 1973 onwards so since my July 1970 carbs still had the original leather accelerator pump cups, which were also recommended for replacement, I'm pretty sure my carbs don't have the new improved vent chimney. I'll have to pull out the photos I took while I had them apart. I bought some spare carbs a while back that I'll check to see which version they have. I did have a carb flooding issue with one of my carbs a while back so this is more than an academic issue for me.
I still have the tower, no issues