Stromberg Carb problem? HELP, HELP, HELP!!!!

[stagmoneypit]

Hi
Can anyone help diagnose this problem? I am trying to start a rebuilt engine which is equipped with a pair of Stromberg 175CD2 carbs, I have replaced all the seals,gaskets, float valves and diaphragms. The symptoms are as follows:-
PS: I have spark and the spark plugs are still dry. New fuel pump delivers plenty of fuel to the float chambers.

1. Fuel pump sound dies away once fuel filter in the engine bay fills up.
2. When the carbs were removed the inlet manifold was full of fuel as if it was not atomising?
3. The dashpot pistons don't seem to rise when the engine is turned over, there is a new o-ring between carb and manifold.
4. Even when the pistons are lifted slightly with screwdriver still nothing happens.
5. When turning over there doesn't seem to be much draw from the inlets when a hand is placed over them

There were a couple of pops and a puff of smoke once but it seems as if the fuel isn't being atomised and is just overflowing through the jet body and collecting in the inlet manifold, what am I doing wrong? Please help before I chuck a match in it and call it a day!!!!!:X:X:X:X:

Glen

[Oldromola]

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Glen - first of all I'm sorry I can't solve your problem as I have only been recently promoted to Junior Technicial(3rd class) and the syllabus doesn't cover such advanced topics as carburettas. However, if it's any comfort to you, I was recently in your postition when the engine refused to start after a rebuild. There were two or three problems if I remember correctly, but the main problem turned out to be an incorrectly set up distributor.

The main point I would like to make is this. Whatever you do, do not take of the carburettas, pour some petrol down the inlet manifol and try to start the engine. You will have a fire before you can say 'hey presto' - believe me! Apart from this rather negative suggestionI am sure you will shortly get the correct advice you are looking for.

[Cheesy]

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Glen - I had exactly the same problems when I tried to start my engine after a bottom end rebuild!Everything seemed to be working OK; healthysparks at the plugs, buthardly anysuction from the inlet, just the odd pop and splutter, and an inlet manifold filling with fuel.

Like you I presumed it to be a carb problem, even though they were reconditioned carbs.

It was actually an ignition problem - the distributor timing set 180 degrees out! As soon as I reset the distributor, the engine fired first turn of the key.

I would recommend removing the fuel from the inlet manifold first; I did it by soaking it up with kitchen roll.

Definitely worth a try.

[stagmoneypit]

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I timed my engine with no.2 piston at tdc, is that correct?, also does it make a difference because the car has lumenition electronic ignition.

[Oldromola]

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I thought 'cheesy's input was very interesting. And by the way, althoughthe Master Technicians amongst us will no doubt deliver their verdict in due course,I think you were correct by timing the engine with No 2 cylinder at tdc.

[stustag]

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Hi Glen

No 2 is the correct cylinder to time from if dynamicallytiming the engine. note this has to be done with the vacuum pipe removed. Have you reattached this afterwards?

Have you set up the control linkage prior to doing anything with the carbs? Page 19.15.02 in the ROM. I can scan and email this if you haven't got one.

Have you set the float heights equally, these should be 16-17mm (0.629-0.669 in) adjust by bending the tabs ensuring the tab sits on the needle valve at right angles.

Have you filled the dashpot with engine oil (new) until by using the damper as a dipstick the threaded plug is 6mm above the dashpot when resistance is felt.

Have you connected the breather pipes which help the dashpot rise?

If you've done all of this already then you should double check everything you have done just in case you have missed something.

Without being there it is very difficult to help but I've always found that it is usually something simple that was missed during assembly that is causing the problem.

Hope you get it going soon and don't have to result to the box of matches!:shock:

Stuart

[stagmoneypit]

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Hi
1. The vacuum pipe was attached
2. can you email me the control linkage info
3. I checked the float height 17mm
4. There was oill in the dashpots

The breather pipes weren't attached.The air cleaner and overflow pipes were also not on the car.
Should the fuel pump stop when the float chambers are full? is there some kind of return valve in the pump?

Glen

[stustag]

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Hi glen

I've sent you my e mail address as a PM, please return and I will send you the info straight away.

Stuart

[boiler0_3]

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HI.

This sounds like a timing problem to me.It is important that when the piston is at TDC it should be on the compression stroke and not the exhaust stroke. You can check this by removing the rocker cover and checking that the valve is closed.

Sorry if you already knew this, but I have made this mistake before.

[Bob Heritage]

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Cheesy wrote:

I would recommend removing the fuel from the inlet manifold first; I did it by soaking it up with kitchen roll.

If you watched Top Gear last Sunday they gave out a brilliant tip, use a tampon to soak it up, every toolbox should have some. If you are sure all the settings are right, try a can of Easy Start or Power Start from any accessory shop, it will almost certainly start the engine.

Bob

[WildStag]

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Bob Heritage wrote:

[snip] If you watched Top Gear last Sunday they gave out a brilliant tip, use a tampon to soak it up, every toolbox should have some.

First it was the dishwasher, now this - SWMBO is looking to be indispensible!

Only trouble is, given the average age of SOC membership, most Stag owning households are more likely to have access to incontinence pads than tampons! :shock::P

[stagmoneypit]

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PASS ME THE MATCHES! still no joy with everything bolted on, inlet full of fuel again,i now am looking at the distributor which looks a bit gunged up inside, seized weights maybe?

Also i have another problem the manual gearbox seems to be stuck in reverse gear even in neutral! You can select other gears as normal, an internal problem? the clutch is working fine though.

[John]

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I had very similar symptoms and it turned out that I had the distributor 180 degrees out - No 2 cylinder at TDC, but on the wrong stroke!

[stagmoneypit]

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Hi
The engine was timed in this way, I took off the cam cover and turned the engine over until both valves were closed on No.2 cylinder and the crank mark lined up with the '0' i checked that the piston was at tdc by removing the plug and putting a screwdriver in the plug hole. The distributor was then inserted so the rotor arm was pointing at the coil retaining bolt as described in the Haynes manual or the No.2 point on the distributor cap, unless i have the ht leads attached one connection offset? What do you think? I will post an image as soon as I can.
Thanks Glen

[GDPR]

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I'm not being obvious here and making sure you haven't put the fuel feed pipe on the carb breather stubs by mistake?This is pretty much the samesize and it serves to allow the float chamber to breathe but if the float fails this is the way out via the pipe for for excess fuel without setting your block on fire...... you would get a whole lot of fuel in the manifold as it's not metered by the floats....

I only say this because I've had apprentices do this silly mistake in the past........not on a Stag admittedly but you can never be too careful

Russ