View Full Version : STROMBERG GURU's needed

07-06-2007, 07:44 AM
Thanks for looking, I've just had a pair of ZS 150's rebuilt and refurbished for my '67 Sunbeam Alpine, They look great! I am however having a few problems with them, the MOST serious is fuel leaking from the "vent" holes above the shafts on the bowls, this happens when the choke is pushed off and the engine is returning to idle (about 8-900 rpm) can't seem to get it to idle below that. The engine will run at 1200rpm and above without any leaks, it's just....well can't let it run that fast all the time.
I've sent them back to the rebuilder a couple times already, and he's changed gaskets(we thought that's where the fuel was coming from) floats, float valves.
ANY thoughts, comments, suggestions, request for more information, directions, help..........
will be greatly appreciated.

Thanks in advance, Tom J

07-06-2007, 08:25 AM

Not a Sunbeam owner, but I've torn down a couple of ZS's before so I have a thought on your problem. I think you may have to adjust the floats in the carbs, as they may be causing the needle valve to be open and allowing too much gas into the bowl and out the vent hole.

Only from memory here, but the solution would be to take off the bottom bowl, inspect the float, make sure they are on the pivot correctly, then measure the float height - someone else can chime in on float height, as an unsubstantiated guess I think it is around 3/8".

If you've had problems with dirty gas your needle valves may be stuck open, but that typically results in a lot of gas coming through the vent hole.

65 TR4

07-06-2007, 09:16 AM
I agree with Randy, probably your float adjustment, and possibly sticking needle valves. Had the same problem on a CD-175, and it was the float height adjustment.

07-06-2007, 03:13 PM
Thanks guys ! We had already added a fuel filter just before the carbs so we also could eliminate the dirty fuel cause, the re-builder has changed out the needle valves... How do you go about adjusting the float height ??

All antidotes welcome, cures are highly valued !

Tom j

07-06-2007, 09:43 PM

Here is a pretty good reference on how to adjust the float:
ZS adjustment link (https://www.autozone.com/az/cds/en_us/0900823d/80/1d/8c/92/0900823d801d8c92/repairInfoPages.htm)

My only caution is that the height adjustments may not be universal so I personally don't know if the heights they talk about are correct for a 150 carb. You may be able to find the specs on the internet with some searching, or get one of those haynes or other tech books on ZS maintenance and rebuilding.


07-06-2007, 09:49 PM
Tom, the float height specified for my 150CD carbs is 18mm from the highest point of the float to the gasket sealing surface, with the carb inverted.

07-07-2007, 08:08 AM
ummm... what's the fuel delivery pressure? Should be no more than 2.5~3 PSI. More will push the fuel past the seats.

Just a WAG. How is it you've Zed-S carbs on a '67 Rootes car? Just curious.

07-07-2007, 09:32 AM
Doc, I'm looking for a fuel pressure gauge(the re-builder also want to know the fuel pressure) any thoughts about a place of purchase? Dual Z S 150 CD's on a 67 Alpine, except for having them work, what more could you ask for?? Actually standard equipment....
Jeff, In my workshop manual it gives the "height" 18mm is in the range, I suppose they really need to be inverted(hoping not to remove them again, although it's getting easier each time)
Randy, thanks for the link..
Thanks again guys,

Tom j

07-09-2007, 07:17 AM

If you are running an aftermarket fuel pump, you really need a fuel pressure regulator. As Doc E says, you really don't need much more than 2 or 3 psi. (I'm racing on 2 psi).

~CLICK HERE~ (https://store.summitracing.com/egnsearch.asp?Ntk=KeywordSearch&DDS=1&Ntt=fuel+pressure+regulator&searchinresults=false&N=+115&y=10&x=39) for various choices. Generally, with these things, the more money you spend, the better off you are.

Summit Racing also have fuel pressure gauges if you browse the catalog.

And yes, be sure float height is set properly too.

Dave Russell
07-09-2007, 08:06 AM
In my opinion & experience the Holley adjustable 1-4 psi - Summit #HLY-12-804 in Nial's reference, is hard to beat for performance & price. It also has an extra port for a gage or return line.

The really cheap regulators with a dial top are a joke & more trouble than they're worth.

07-09-2007, 08:17 AM
The really cheap regulators with a dial top are a joke & more trouble than they're worth.

Yup. I've seen those do everything from spontaneously "self-adjust" to actually go to pieces and allow fuel to be "distributed" all over the engine bay. Baaad ju-ju.

07-12-2007, 05:48 AM
THANKS to all !!
Got one of those Holly regulators WOW engine fired right up, ran up to temp, spewed no fuel(most important) and I think after a few tweeks and fine adjustments, we'll be ripping around the streets of Atlanta and the surrounding suburbs.
A little float adjustment helped also.....
After "only" 10 months (I know it's not really that long) to sit behind the wheel and drive somewhere...............

Tom j

tony barnhill
07-25-2007, 08:08 AM
Tom - don't know if this tech tip on Strombergs will ever be of help with your setup or not, but here 'tis:


07-25-2007, 05:56 PM
Thanks Tony.. But the link didn't work..
Couple of months ago.. drove through Gurley, I didn't see you /bcforum/images/%%GRAEMLIN_URL%%/smile.gif We were on the main road(highway)on the way to Huntsville to pick up a '66 Alpine, fun ride back to Atlanta except the alternator wasn't charging.. after a couple jump starts to charge the battery we took the "red top" out of my truck and drove home on it without stopping except for fuel.............

Tom J

tony barnhill
07-25-2007, 06:23 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]the link didn't work..[/QUOTE]

Server issue - give it about 15 minutes & the problem should be solved.

If you were traveling on US72E, I'm 2 miles off it! We could've solved your charging issue before you got on the road.

07-25-2007, 08:13 PM
Tony, If I get over that way again I'll find ya ! Got any Sunbeam goodies? '66-67 Alpines.
I've sort of been clearing Alabama of Alpines(2) Problem is if I find any more I'll be living in them (directive from the BOSS):0 !
Tom J

Those servers.... are they all made in England ? Or just wired by Lucas !!