Stromberg CD150SEV Float Chamber Vent Valve

[GT6_Mark]

Prodding around my '73 GT6 Mk3 this past weekend I noticed that I am missing a float chamber vent valve lever on one of my CD150SEVs. It is the part I have colored yellow in this image:

It seems to be marked as "not available" from the usual sources. Anyone have one to sell, or a tip on where I might be able to buy one? Thanks.

 

[RonMacPherson]

Have you tried Joe Curto?

 

[Dennis]

Not sure, I have an extra pair of carbs sitting at home. I have a red x for the picture. If you could fix that it would help.
Dennis

 

[GT6_Mark]

Have you tried Joe Curto?

No, but I have now searched for Joe and found the following information, which I will follow up later:

Joe Curto, Inc., 22-09 126th Street, College Point, NY 11356, Tel: (718)762-SUSU (7878) Fax: (718)762-6287 https://www.joecurto.com/.

Thanks.

 

[GT6_Mark]

Dear Dennis,

Tried to relink image above. I hope it works and have copied it here as well:

I hope you can help.

 

[Dennis]

Hi Mark,
Sorry about that, they are the earlier carbs. They don't have the vent valve lever.
Dennis

 

[rotoflex]

My spares set is also the earlier 150CDSE type without that vent valve.

I also recommend calling Joe Curto. It will likely be an item someone can provide from a used junker carb.

Some more sources that rebuild Strombergs & may have parts carbs around:

Apple Hydraulics
https://www.applehydraulics.com/

And if you must go worldwide, you could email
Burlen Fuel Systems
https://www.burlen.co.uk/

Andrew Turner
https://www.su-carbs.co.uk/

If I remember what I read of the function of that later addition to the CDSE, it seems like it was to partially seal the float chamber from atmospheric pressure on rapid deceleration so as to further impede using fuel in deceleration. I'll bet that, until you find a replacement lever, you just block both those valves in both carbs to the open (non-idle) position, you'll do fine (you'll basically have the earlier CDSE without that valve).

Good luck.

 

[GT6_Mark]

Thanks guys. I'll try and follow up with Joe Curto. If I have to make a temporary fix it will be pretty easy to take the lever off the other carb and rig it so that neither float chambers are venting via the cannister on idle. I have had an erratic idle recently that I have not bothered to track down - its been driving weather not fixing weather - so I am curious to see if this improves when I get this vent valve fixed. I'll let you know. Mark

 

[rotoflex]

One cause of an erratic idle on the CDSE's can be deterioration of the sealing washer at the screw end of the bypass valve assembly.

If you disassemble the bypass valve(s), you can lightly grip with needle-nose pliers the brass adjuster from the inside & withdraw it. There should be a screw head on the other end, with a rubber washer around it.

The rubber washer can deteriorate, especially if the bypass valve has been cleaned in some parts cleaner without replacing the washer. Or even just from age.

My rebuild kit from Joe Curto had the correct replacement washer.

If your bypass valve is one which has the brass plug in the end so that the screw head is not showing outside, it is very easy to tap out once the adjuster is extracted as described above. You will need the screw head exposed to set the carb(s) back up when back on the car.

Setting the bypass valve back up after disassembling it is I think described in the BL emissions booklet which also shows/describes the float chamber valve on the CDSEV. If you don't have that booklet, let me know & I'll locate my copy & instructions.

Also, it may be further than you plan to go at this stage, but the throttle shaft should not be scored, & new seals should be in place if the carb body has been soaked in parts cleaner.

 

[GT6_Mark]

I dug through a box of 20 or so Strombergs at a local scrap yard this afternoon. Mostly 175s and not one 150CDSEV. However, I lucked out and found what I needed in the debris in the bottom of the box! I cleaned up the part and have posted these pictures in case anyone is interested in seeing what I was after:

I’ll fit the new part tomorrow and see if the idle improves. If it does not, my next lot of tinkering will be to overhaul the by-pass valves with kits from Joe Cuto as suggested.

Thanks for the pointers.

 

[GT6_Mark]

Just an update for anyone interested in my float vent valve saga.

When I went to fit the replacement vent valve lever for the one which was missing off my front carburetor, it became obvious that the small brass pin assembly on which it acts was seized. Checking the rear carburetor confirmed that the pin there was seized as well despite the fact that this did already have the correct vent valve lever.

Copious squirts of PB Blaster and use of air over a period of a few days did nothing. A quick check with Joe Curto confirmed the need to take more drastic action. Seeing if getting to the inside end of the brass pin assembly by pulling the drilling/airway plug would help.

Nice easy on-the car job. Punch, drill and tap the plug 5/16” UNC. Pull plug. Easy access to the other end of the brass pin assembly. Squirt of PB Blaster and a light push on the pin end and voila! Freed pin. A little more working and everything was just fine.

I did polish the exposed end of the brass pin using a small wire brush on the end of a Dremel before fitting the vent valve lever back.

I used helicopter tape to seal the drilling/airway as a temporary measure so that I could a quick road test check. With the car up to temperature, I did an initial set-up the vent valve. Everything seems fine.

I’ll source and fit some replacement plugs this week and do a final set-up for the vent valve.

 

[poolboy]

Nice. Persistence pays off.

 

[GT6_Mark]

OK. Finished the job tonight by fitting my new steel plugs.