More Stromberg problems

Tips and help requests for your cars mechanics. points gaps, timming settings all those sorts of things

Re: More Stromberg problems

Postby Mike Robinson » Tue Jul 17, 2018 11:01 pm

Dave, I updated the ignition system about 18 months ago: Accuspark, new coil, plugs and leads. I have checked the spark, nice and blue and juicy and it starts and restarts and idles in all conditions, hot and cold so I really don't think it's ignition. When it cuts out its a relatively slow process. I think electrical faults tend to be more sudden.

Lord13, I dont have a spare Stromberg but a replacement is my current plan B!

Mike, I'm sorry but I don't quite follow you. I supposed all BIEU are the same with a cylindrical "body" which just slides into a cylindrical hole in the piston. When it is fully in you can insert the locking grub screw which goes through the wall of the piston into the end of a slot in the side of the body, locking it in place. (a photo would have been better but I'm not in a carb stripping mood.) Mine only goes in in one position, no adjustment possible.

Regards Mike
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Re: More Stromberg problems

Postby lord13 » Wed Jul 18, 2018 8:06 am

I may have a stromberg you could borrow to see if it is your carb, I did have a few kicking around, although I may have left it in the box I left in the back of my HB when I sold it :( it will need a piston spring fitting but everything else is there and it does work. I had it on my HB for a while but it was overfuelling slightly, it's a chevette one I think, doesn't adjust by the bottom jet as that is sealed, it adjusts via the dashpot with a special tool, but it does work, I'll look in my shed later and if you PM me your address I'll send it to you for testing purposes :)
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Re: More Stromberg problems

Postby Mike Attew » Wed Jul 18, 2018 8:13 am

Mike, I'm sorry but I don't quite follow you. I supposed all BIEU are the same with a cylindrical "body" which just slides into a cylindrical hole in the piston. When it is fully in you can insert the locking grub screw which goes through the wall of the piston into the end of a slot in the side of the body, locking it in place. (a photo would have been better but I'm not in a carb stripping mood.) Mine only goes in in one position, no adjustment possible.

Regards Mike[/quote]

Hi, They do not just slide in, in the end of the needle collar is a thread, in the bottom of the piston is a thread. you push the needle in until it goes in a far as possible , then you screw it in the rest of the way. If it does not screw in somebody as possibly forced the needle out and stripped the piston thread sometime. This may be a source to your problem. The locking grub screw screws into the groove to stop the needle assembly from unscrewing out of the piston.
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Re: More Stromberg problems

Postby 1972nail » Wed Jul 18, 2018 10:41 am

From what you say it seems most likely to be fuel related.

Mike's needle screw in diagnosis sounds worth checking but worth checking also would your breather pipe to the tank. If it is blocked, crushed, kinked etc is may be creating a partial vacuum in the tank. Try running with the fuel cap off and see if that helps. Don't run an anything fuller than half a tank as you'll risk spilling fuel out on fast roundabouts.
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Re: More Stromberg problems

Postby Mike Attew » Mon Jul 23, 2018 7:55 pm

Did you sort this problem Mike?
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Re: More Stromberg problems

Postby fistfullofV5's » Thu Jul 26, 2018 11:48 pm

Mike Attew wrote:Did you sort this problem Mike?

Yes, I was wondering who had won the Stromberg fault diagnosis quiz as well.
Regards, Dave.
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Re: More Stromberg problems

Postby Mike Robinson » Fri Aug 17, 2018 9:03 pm

Hi guys, Sorry I failed to follow up, have been off the Viva for a while.

Mike A, I looked again at the needle to air piston connection then remembered the threads. Previously I hadn't found the thread engaged significantly (the threads locked up). By tapping the needle round I got about half a turn engaged to get the grub screw to line up with the location slot. This lowered the needle about 0.6mm only so it protruded by 1.2mm from the piston. Unsurprisingly it didn't produce any significant effect.

I did some further tests which confirms the problem is definitely that the float chamber does not refill quickly enough due to a problem within the carb. As the needle valve is free (I've tried a new replacement), I don't think the float could stick up and release regularly, so I guess there's a restriction or partial obstruction in the passages. (I had a mummified fly one time!). The effectively unvented float chamber bothers me a bit too.

Lord13, Thanks for the offer of the loan carb but rather than spend any more time on the Strommie set-up at present, I have just re-installed my old Nikki twin choke system. This starts, runs and accelerates normally and seems to run better than before. Anyway just getting out in the Viva always makes me run better!

Mike
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Re: More Stromberg problems

Postby droopsnoot » Sat Aug 18, 2018 6:01 pm

Mike Robinson wrote:The effectively unvented float chamber bothers me a bit too.


Is it un-vented? I'm having trouble with my Sportshatch at the moment, in that fuel pours out of the front carb through the hole marked in the picture, and the general consensus is that it's because the needle valve is sticking open. This suggests that the hole the fuel is pouring out of when the pump continues to pump is actually a vent hole. Haven't yet found any mention of it in several guides to the carb.

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Re: More Stromberg problems

Postby Mike Robinson » Sat Aug 18, 2018 9:13 pm

Mike, I found that when you tip up a carb full of petrol it pours freely out of the "vent" pipe. On mine, when the carb is empty of fuel, if you blow in the vent pipe air comes out of the filler pipe, but if you blow into the filler pipe very little air comes out of the vent pipe, which obviously seems curious. I've read somewhere that in emission controlled installations the venting is controlled (maybe to a a charcoal cannister system?)

Mike

I've just looked properly at your photo. My carb is different and has a purpose built vent tube. Should have put the wine down before replying!
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Re: More Stromberg problems

Postby droopsnoot » Sun Aug 19, 2018 6:45 pm

I've got three different ages of CD175 in the shed, and they all seem slightly different around that area. There is talk about a canister connection in one of the PDFs I'm reading - it's aimed at BL cars sold into the USA, so emissions were a hot topic.
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