Overflowing CD150

[thebrookster]

Ok. New fuel pump has arrived, and been fitted. Engine run and carbs roughly dialled in.

I discovered that neither carb was happy, so whipped them off and opened the float chambers. Turns out the front carb has a different style of chamber which does not fit the gasket supplied. Not only that the gasket from the kit was jamming the floats shut, so no fuel. So, new gasket fabricated, all working.

Rear carb - Again I had to trim the gasket as it was catching the floats, so they weren't closing, causing the carb pour fuel everywhere. Took the car for a brief spin to check how everything was, after a mile or so I lost power. Pulled into a side, and when I pressed the clutch the engine died. Opened the bonnet to find the rear carb again pouring fuel out through the overflow/breather. Removed and opened the carb again, nothing obvious. Fitted it all back again, started the pump and still pouring out. This time however the engine started, and once running the overflow stopped.

I am not running any huge pressure on fuel (pump is a Huco suction pump running at 1.4 psi).

Anyone got any suggestions as to where I go next? (And believe me, EFI is starting to look very promising!!) For a simple carb these are becoming a bit of a nuiscence. Rebuild kits I got were official Zenith kits (CDSK 11 for 125/150CDS, GRN No. 32115, however so far I have had following issues:

Diaphragms too stiff and not allowing pistons to fall to bottom position properly
Wrong gasket (though this may well be a bastard carb issue!!)

Cheers,

Phil

[dazzer]

Hi Phil

The Strombergs should give you no problem set up with correct parts. I'm wondering whether the kits are actually the real thing? Did you get them from Burlen or Gower & Lee or similar? I've come across thick rubber diaphragms before that were sourced on eBay. It might also be the centering of the jets that could be causing the pistons to stick and not falling to the bottom position. Have you checked the float heights? I've also come across 150CDs with leaking needle valves because of crud coming from the original steel pipe that loops between the two carbs. at the bottom of the loop corrosion collects and then moves to the needle valves holding them open.

Hope this helps.

Cheers
Darren

[thebrookster]

Quoted from dazzer

Hi Phil

The Strombergs should give you no problem set up with correct parts. I'm wondering whether the kits are actually the real thing? Did you get them from Burlen or Gower & Lee or similar? I've come across thick rubber diaphragms before that were sourced on eBay. It might also be the centering of the jets that could be causing the pistons to stick and not falling to the bottom position. Have you checked the float heights? I've also come across 150CDs with leaking needle valves because of crud coming from the original steel pipe that loops between the two carbs. at the bottom of the loop corrosion collects and then moves to the needle valves holding them open.

Hope this helps.

Cheers
Darren

Hi Darren - Thanks for the reply!! To answer your questions:

Kits - came from Chic Doig, he normally uses correct stuff??
Pistons sticking - I checked that The piston would fall to the bottom without the cover fitted, but as soon as I fastened the cover on the piston would lift by several mm!!
Float heights - set to 18mm as per manual
Needle valves - Brand new. New rubber pipes fitted, I only have two short sections of the metal pipe at the carbs, one chunk has been replaced by rubber by a PO.

Incindentally, whilst looking around on t'interwebs, I found some references to what numbers were used where. Having checked my carbs, I would appear to def not have a matching set.
Front carb has # C1854F, which Burlen says come from a '64 - '65 Mk1 2000.
Rear carb has # 3137FN - not found where this comes from yet!!

Wrong kit looks quite likely, but what is the right kit! Maybe simply getting two new carbs is the best bet, if they are actually matching!!

Cheers,

Phil

[thescrapman]

Quoted from thebrookster

Wrong kit looks quite likely, but what is the right kit! Maybe simply getting two new carbs is the best bet, if they are actually matching!!

Cheers,

Phil

The ones Andy is selling are not the original matched pair. A PO had hammered the jet assembly into the body of one of the carb after he stripped the threads. It ended up about 5mm too low and wonky.

So I used a 13/60 carb body to fit it.

Cheers

[Nick Jones]

Leaky needle valves on Strombergs is very typical behaviour and they usually do it after being disturbed and settle down after a little use (a whack on the side often stops then leak).  Sometimes the problem is a sliver of rubber scalped from the inside of the fuel pipe when pushed onto the stub on the carb body (apparently specially sharpened for the purpose) and then lodged in the needle valve.

Strombergs are good once working right but can try your patience getting there.

Nick

[Pete Lewis]

most kits have a selection of float gaskets in them , there was a lot of evolution which is easy to get the gasket with the wrong profile and the float chambers leak out

where's  the flood coming from , the float bowl , underside or out the jet or the front face breather port ???

Pete

[thescrapman]

One thing that also caught me once, a particular combination of gasket and float causes the latter to just catch on the former, causing flooding.

Fit the correct gasket and all is fine again.

Cheers

[thebrookster]

Overflow is from the front facing breather port, and pumping out in style!

Colin is partially correct, I was having issues with gaskets and floats, which was causing overflowing, but I have rectified, checked and double checked them since. It would appear to be the needle valve not sealing properly now.

I have been away for weekend, so when I get back later on I may have another go, was getting quite fustrated with it so a couple of days away was good!

Cheers,

Phil

[Pete Lewis]

needle valves across the su and stromberg ranges seem to be getting problems,

recent finds ive come across are Grose jets are now hopeless, su floats wearing at needle contact pitches the needle, stromberg jets supplied with full fitting needle and no outlet ports ( empty ,not flooding)
the later stromberg needle valves with a wiggly needle , no ports but fuel flows around the needle seem OK

always check if you have a twin armed  stromberg  float that its the right way up. !!!

slivers of rubber are breeding in the system every time you refit a hose ,  damned cussed little swines

pete

[thebrookster]

Well, the saga has continued.

Between the set of carbs from mrshed, and my set I managed to rebuild my carbs with correct bits. The ideal would have been to use the new set of carbs as they were (since they were known to be good) however I did not have enough bits and pieces to convert the throttle system over (I have the original rod throttle, and the replacement carbs were for the cable style).

However in the process I managed to break one of the little lugs for the float. I repaired this with some "Super Steel Epoxy Weld" from Halfrauds, as it claimed to fix just about everything. Worked fine last week, so I booked an MOT for today.
This morning I went out to start the car, and again fuel pouring out the breather. So rang the garage and cancelled the MOT (second one cancelled now). After some serious pondering about options (ranging from opening them myself, sending them to Andrew Turner to considering going straight for EFI) I suddenly (yet again) remembered that I have Herald 13/60 sat on the drive, and if memory served correctly it had a single Stromberg carb! So out I popped, and lo and behold one CD150 carb, of a matching type to mine. So a quick dis-assemble on both cars, and some swapping of parts around (as I needed the throttle spindle swapped as the linkage for the two is pinned on) I suddenly had a new carb.

It would appear that the lug I tried to repair has detached itself again, obviously the wonderful Epoxy Weld was not quite as wonderful as I had hoped.

Anyway, I rebuilt and re-attached everything back onto the 2000, and set all the mixtures etc to book figures (jet 3 turns down from bridge, and idle screw in 1 full turn from touching). Connected the choke, and on full choke managed to get the engine started, but not running. Wound the idle screws in another two turns and away we went.

Once the engine was back up to temperature I tried taking the choke off, however as soon as the choke was removed the engine died. I then realised that the rear carb was leaking petrol out the breather, but only slightly and a wee tap soon cured that. Wound the jets out some more, and eventually got started again, so away I went with tuning. I got both carbs tuned roughly in, idling nicely however the rear carb seemed to want a lot more enrichening than the front, which began raising some questions.

Achh well, in for a penny, in for pound. Off came the rear carb, and popped the float chamber off. Turns out some wazzock had only gone and fitted the pin holding the float in the wrong way round, which had allowed the float to semi detach itself. Well, at least that was an easy fix! So, popped it all back together again, and we were much happier.

I have to say, I am slightly staggered by how much I have had too wind the jets out to get the mixture correct. Started at 3 turns down, no go at all. I eventually ended up going another 3 turns again, but then wound it back one turn for a quick test drive, and found that was just slightly too lean. Ok once going, but stagnated on setting off and when I tried ambling in second gear at low revs applying the accelerator caused a distinct lurch. I then progressively kept lowering the jets bit by bit, and found I am back at roughly the three turns again (so 6 turns from bridge). I can only assume that this has something to do with the "PI" camshaft that is fitted, as both float levels are correctly set at 18mm, and everything else is good. New jets, needles centered nicely, oil in the dashpots. Ohh, and the needles are 6J if that makes a difference!

So, spoken to the garage again, as we shall now go for 3rd time lucky on Thursday. At the very least the car shall hopefully be able to make it off the darn driveway this time!

Now, does anyone have any advice regarding good quality epoxy/liquid metal for repairing this broken lug on my now spare carb body? Obviously it needs to cope with being immersed in petrol? If I can repair it I might keep that carb as a spare body.

Ohh, and hopefully one day the poor Herald will actually get restored, instead of being a spares parts donor! Ohh, for some spare time!

Cheers,

Phil

[richard w]

Glad you got it running Phil. Let's hope it keeps going OK for the MOT.

Richard

[thebrookster]

Well, MOT is done and passed!!

I was a wee bit concerned this morning driving in as I had a slight stutter, which I was fairly confident was the fuel filter being choked. And I had left my spare at home. But fortunately traffic was slow, so got her over to Helensburgh.

MOT went well, the garage were very helpful (and in fact had me assisting as the lad admitted he was out his depth!) Technically my front pads were borderline fail, but as I could show him the full set of NOS pads in car waiting to go on, he said if it passed the brake test he put it as an advisory. Fine. We also discussed the Brake test, and mutually agreed to ignore the roller, and instead go the old fashioned route of a decelerometer. Perfect, except the car would not start! So I got stuck in. Pump was not pumping, so they found a replacement filter (well found a couple old ones then found a new one) which was fitted. No luck. Blew back up the fuel line from the pump, flowing fine. Then I removed the pipe from the carbs and the pump started pumping. After a short while I got fuel.

My guess there was vapourlock. Except I still could not start the engine! The I realised the lads (I had several of them round the car at this point) had helpfully tried pulling the choke out, except the engine was already hot! No wonder she would not start.

Choke back in, couple of turns of the key, and away she went. Out for the brake test, and passed.

I also got two other advisories - one for gaitor condition on a ball joint which I agreed with, and the other was front wheel bearings have slight play! I hadn't realised he had put that on, but not really important anyway, I had given the wheels a good shuggle when it was up and I am happy with it. Lack of knowledge on the testers part I suspect there.

So, she is back on the road again. Now to fit the new pads, and we are happy!

Cheers,

Phil

[Shed 1969]

Nice one well done!

[Shed 1969]

as an aside I would still  go for converting rod throttle to cable and use a modern cable gives the pedal such a nice feel !

[richard w]

Congratulations Phil!