Near disaster from carb

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David Jones
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Re: Near disaster from carb

#31 Post by David Jones »

Only means it has been a while since the carb was opened up. Tap it hard with the plastic end of the screwdriver you loosened the top screws with, it will come loose. Before you do anything else after you get the top off carefully remove the float valve being sure to not lose any of the fibre washers under it. They can help in setting the float level. Once you have changed the float valve you will want to set the float level. That can be accomplished by using a long length of tubing attached to the fuel inlet with a funnel attached the other end and set about 7.5 feet above the carb. Fill the tube with mineral spirits which is the same SG as gasoline the set the float level. You do this by removing the plug on the side of the float bowl and then adjusting the float from the screw with lock nut on the other side (same side as the jets)
Do you have a factory workshop manual? The method is set out in there.
Also before reassembly check the accelerator pumps for correct operation and quantity. About 0.5 cc for two strokes. If you find as is likely they do not work too well buy the kit that has the diaphragms in it.
If I had known I would live this long I would have pushed the envelope a little harder.
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David Jones
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#32 Post by David Jones »

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If I had known I would live this long I would have pushed the envelope a little harder.
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JohnLiles
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Re: Near disaster from carb

#33 Post by JohnLiles »

Hi Mitch , am reading your thread with interest as have had similar experience . My car was recently acquired at the time and I had never gone too far in it or had more than a couple of gallons of fuel in the tank - 1955 car with 1967 ( 912) engine , Solex carbs.

I was booked in for a 356 event some 100 miles away and having to make early start in morning , so previous night I went and filled the tank ( for the first time) . In the morning , still dark , backed car out of garage , go to close door , see BIG dark patch on floor . Luckily I bent down and smeared some on my finger , smelt like oil but felt like petrol - thin. Car was sat outside ticking over but some sixth sense said put it back , switch it off , write off the drive and event . Went back a few hours later , when light , started looking, checked oil , dipstick reading too high , felt like oil but smelt like petrol !!
The real culprit was not turning the gas cock off after filling the tank , gravity did the rest with fuel level above carb. Only 1 carb was passing fuel . I did change the oil and did check float (OK) , also noted that carb was dripping from throttle shaft . I continued to use car for a few months then , decided would get both carbs rebuilt to solve leaking shaft , only just got that done . Am pleased with result . Am now doing the initial carb adjustment myself , then might get expert to do proper set up , main lesson - turn off fuel tap to Zu when not in use !
1957 'A' and 1955 'Continental Outlaw'

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Mitch Covington
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Re: Near disaster from carb

#34 Post by Mitch Covington »

David -- thanks! I've been reading up on Solex carbs all day but learn more from you guys in 2 minutes than I can all day searching around. I don't have the factory manual, but see more and more that if i'm going to do big boy projects on the car, I better ante up! I will try a simple rebuild instead of sending the carbs in for major restore.

John -- glad to hear your story. I've never shut off that valve before and no problem for years. Now I see that it's the prudent thing to do and will never let my car sit with it open for any length of time at all. Keep me posted on your carb tuning ... i'll be doing that soon too.
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Bruce Smith
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Re: Near disaster from carb

#35 Post by Bruce Smith »

Mitch -

Harry Bieker wrote up a nice procedure you can find here: https://porsche356registry.org/article/47. The 356 workshop manual is good as is the 912 "orange book" for Solex carbs. Keep track of where your washers belong as you take them apart. This helps when you sort out the new ones and you may find you'll want to use some of them. Check that the throttle plates (butterflies) close off completely with the idle screw turned out. If they do, there's probably no need for machining. The accelerator pump gaskets can be a bit tricky but not too bad. If your pumps work, you could choose not to change them BUT they may be brittle and close to failing. Do one carb at a time so you can use the other one as a model. The throttle levers and hardware are the only differences. If you take your time with a rebuild kit, and do a good job, you'll be set for many many miles.
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Re: Near disaster from carb

#36 Post by Doug McDonnell »

There is no substitute for experience. If just cleaning the jet doesn't do it or if your problem is a sunk float. Stop,and send them to Bruce.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Re: Near disaster from carb

#37 Post by Mike Horton »

Late to the party, but has anyone asked if these Solex are the early single throat type, or the later dual throat 40 P II,
Mike

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Re: Near disaster from carb

#38 Post by Mitch Covington »

Here are pics from my left carb. There's crap in the space where the needle valve resides, perhaps that was the cause of it sticking and flooding the engine?

The float looked good to my untrained eye, and it definitely had no gas inside when I shook it next to my ear.

I have rebuild kit ordered, and will very carefully clean and replace what I comfortably can with the documentation and suggestions available.

So far, this is fun and fulfilling!

Hope I'm not overloading the forum with too many pics and posts.

mitch
Attachments
Cov needle valve 1.jpg
Cov carb cover off 1.jpg
Cov Solex carb bottom.jpg
Cov Solex carb top.jpg
Cov Solex carb front.jpg
Mitch Covington
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'79 911 SC Targa

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Re: Near disaster from carb

#39 Post by Mike Horton »

Mitch, be sure your supplier sends you the kits for single shaft Solex, the idle mixture needles are different from the split shaft version... have Fun!
Mike

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Martin Benade
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Re: Near disaster from carb

#40 Post by Martin Benade »

I had little chips like that once, (your first picture) they would clog the float valve almost completely so it would idle fine but run out of fuel half way through first gear. It did not ever hold the valve open although I suppose it could have.
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Mitch Covington
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Re: Near disaster from carb

#41 Post by Mitch Covington »

While I'm waiting for the rebuilt kit, is there something I should be doing to facilitate that, such as soaking carb/parts in carb cleaner? Any pitfalls, or common mistakes, that I should be careful to avoid?

I'll photograph everything before I remove it so that I am sure to put the same thing back into the same place.
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'59 356 Cabriolet
'79 911 SC Targa

WilliamVaughan
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Re: Near disaster from carb

#42 Post by WilliamVaughan »

The list of pitfalls is long.
I don't know if the solid shaft Solexes have the little brass orifice between the accel pump chambers and the float chamber. It is about the size of a grain of rice. It can fall out. Don't loose it. It might easily become swept away in a wash.

Do not bend the feet of the carb when you reinstall it. The mounting nuts do not need to be "cranked" tight. The carb is not going to get away.

Don't swap the air correction jets for idle and high speed enrichment.

Don't over tighten the fasteners for the lid.

Make sure the springs for the float mechanism are through the gasket before closing it up.

Be gentle with the float level adjustment screw.

Don't over torque the idle jets and squash them.

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Re: Near disaster from carb

#43 Post by Michael Foster »

Haven't read whole thread so it might have already been posted, but your carb top is missing overflow tube. That may cause some issues.

Michael Foster
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Mitch Covington
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Re: Near disaster from carb

#44 Post by Mitch Covington »

MICHAEL FOSTER wrote:Haven't read whole thread so it might have already been posted, but your carb top is missing overflow tube. That may cause some issues.

Michael Foster
Hmmm... nobody has mentioned that and I did not knowingly remove that. I don't see anything labeled as 'overflow tube' in the shop manual, could that be the 'float chamber vent'?

thanks for pointing that out Michael!
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Re: Near disaster from carb

#45 Post by Michael Foster »

brass tube about 2" on that carb top right in middle staked on underside of carb. For viewing only check ebay for picture no affiliation.

Check here for expediency only
http://www.ebay.com/itm/Pair-of-Solex-4 ... 01?vxp=mtr
MICHAEL FOSTER

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