Any experience purging carbs when gas has been sitting in them of too long?

For the carbs you really need to take everything apart and soak it in a carb cleaner liquid. 3-4 years means everything will have a sticky gunk on it. I'm not familliar with Webers and how much has to come apart but if you have the Wilkins book it's a great step by step guide.

Fuel lines should really be replaced. You can blow them out with compressed air but they're probably pretty old as it is and I wouldn't even think twice about replacing them. You'll have peace of mind that way. Be sure to use brass T's at the junctions. Some old cars with duel fuel tanks (like mine) came with plastic T's and they crack with age.

Ken

 

Agree with Ken - you will need to let them soak in carb cleaner (nasty stuff! careful!) to remove the stubborn varnish, followed by copious compressed air.
Absolutely replace all of the fuel lones. Modern american fuel line is terrific and inexpensive - it will save a fire.
I would go ahead and just get all new jetting, especially idles if nothing else. It doesn't take much varnish buildup to have unequal flows between barrels that you'll be wondering why you can't tune out. It's cheap.

Soapbox:
If it is the original jetting that came in the car in the 70s, they were jetted for 70s gas, which is way different in 2008. At a minimum in a 308 you may want to consider upping to a 135 or 140 main jet, if you have not already.

 

I recently took apart the carbs in my old Ducati that sat for about a year. You know what that "Sugar in the Raw" sugar looks like? Sort of small brownish cubes? That's what I had in the bottom of the bowl, except these were a little squishy. No way you're gonna flush that out of a carb except by removing the bowl. I don't know if that is a new gas formulation byproduct or if I cleaned it out before it became hard, but I'd never seen that stuff in old carbs before.

And you know, the old bike idles SO much better now without that stuff in there!

 

Not trying to ba a smarta*s but it is important to use Stabil or another fuel preserative. l had a motorcycle sit for 4 years with Stabil in the gas and it started right up.

Need to run the car some to get the presevative throughout the fuel system

 

If you are familiar with the carbs it's not too hard to clean them out, you might get by without disassembling too much.

I would remove the carb tops, clean the needle valves with carb cleaner, spray some through each jet orifice, carefully blow everything out with compressed air and reassemble. If you don't know exactly what I'm referring to, STOP HERE and take it to someone who does.

You can drain the fuel tanks from the plug that is in the middle of the crossover pipe between the tanks (might want to siphon first if they are quite full).

I would add a few gallons of fresh fuel and then purge the fuel lines leading to the carbs before reconnecting it to the carbs you just cleaned.

This is messy and there is the ever present fire hazard so BE CAREFUL and keep at least one good extinguisher handy.

 

I would use GREAT caution with this. Both my cars drain plugs are frozen and will not turn. On the one, once I had the pipe out of the car, I have heated it profusely, used penetrating oils, and used an impact socket all to no avail. The pipe itself is rather light, and can easily deform (ask me how I know). It was a great idea to have there if people would only have used them once in a while, but after 30 years of never being broke loose I think I would need to drill it.

While I agree you have a very good chance to be able to get them working on the car with cleaners and the like, there are a great number of screws and jets and passageways, and working over the car in that position is horrid. By the time you have the airbox removed, fuel lines, etc., its maybe another half hours work to pull the carbs. I think once your down to the point where you could start removing the top covers, removing the carbs all together and cleaning them thoroughly will prove the most efficient course. Might be a good time to replace those two top coolant hoses under the manifolds too, while your in there.

 

Don't sweat the work. It takes 5 screws to remove the top. The hard work comes after you put everything back, it is called carb balancing. For a perfectionist such as yourself, I think you would have jumped at the chance of removing and rebuilding yet one more thing.

 

On my GT4 that plug came out ok. Maybe it has been out before, maybe the factory used anti-sieze that day, maybe I got lucky, maybe I'm really good. Even then, I would not pull this plug to drain the gas. That's a big hole, gas flows quickly, and even if the tanks are close to dry it will be a bunch of gas coming at you quickly. I guarantee a mess at best, and at worst - yikes!

I removed the fuel feed to the engine (in my case FI, in your case carbs) and stuck the end in a jerry can. I put the key in "run" position and the fuel pump came on and pumped gas into the jerry can. When the fuel got low I used a floor jack to jack up the passenger's side of the car to slosh all of the fuel I could to the pick up in the left tank. When the pump ran dry there was very little fuel left in the tanks. So little that if you're not removing tanks or the lower fuel hoses, I would just leave it and dilute it with fresh fuel.

If I had carbs and a low-pressure fuel pump I would have bought a hose barb and some tube and made the hose longer to have the jerry can located on the ground and not in the engine bay.

Good luck!

 

If you can comprehend the OWM, removing, rebuilding and installing the carbs is really only time consuming. Exploded diagrams of the carbs are all over the web, there are some very good manuals available, and between the instructions in the OWM and Birdmans instructions available here by doing a search, balancing is really not difficult.

And the kicker is, once you go through it and figure it out, you will realise how incredibly simple they are and will probably fall in love with the car all over again. Once set up properly you wont need to fiddle them for years, easily from one service to the next as long as the car doesnt sit for long periods.

 

Chris,

If time is on your side you might want to hold off a few days on the hoses. This is not a localized issue and does present a concern, something is wrong.
If the hoses need replacement right away use Only SAE30R9 spec as it doesnt seem to happen to this hose, at least not right away in my experiance.
A problem I am dealing with is the fuel neck and tank cross over hose I have been using (Gates / NAPA) once in a while is SAE 30R7 spec and I have not found any availabilty in the R9 spec. I have had no failures (leaking) of these but based upon what I saw with the smaller diameter hose of the same spec there is a concern that needs to be dealt with. I expect to hear from the engineers on Monday as they will have had time with multuple samples I sent to them.

http://ferrarichat.com/forum/showthread.php?t=216915

Dave

 

... just remember when soaking the carbs in the cleaner -- the cleaner makes an excellent furniture (kitchen table) finish remover. I have never seen a finish remover for wood that works faster or cleaner than carb cleaner. Oh yea, I am still getting grief about the kitchen table. This was after my daughter found pictures of the carbs on the granite counter tops on my laptop. Granite does give you a nice surface for using fine grit sand paper to polish the bottom plates of carbs.

 

I rebuild fuel distributors for a living, and I have seen lots of varnish and gum it does not clean up easy, but Berryman B-12 Chemtool is about the strongest cleaner I've found. Be careful it will remove paint and hyde.

Lary Fletcher
CIS Flow Tech Llc

 

If you use the carb cleaner or other harsh cleaners is there any percautions relating to the throttle shaft bearings?

 

Now THATS funny, and all too true!

I had an owner in last week that was doing his own service and I was helping with a few aspects. We got to talking and he said he had to arrange a shopping trip for his wife to gain access to the oven for wrinkle painting the cam covers. Thankfully the weather was good and he was able to do it with the windows open and fans running. We laughed about that and then he said he waited until the dishwasher was full and snuck some "extra's" in there before start up. Busted!
When the granite went in our house Kris had the counter guys do a clean cut out for the sink and set it in the garage. "This one is mine and that one is yours" was the statement. Twenty Eight years of marriage has shown her every scam in the book and she got wise to them all. Every one except the soldering gun radiating enough heat to bubble the finish on the kitchen table while prototyping the fusebox fix one weekend. That one will cost me dearly!

Dave

 

Regarding the fuel hose I spoke about in an earlier post.

Numerous phone conversations with Gates officials this last week with no real results. The problem I explained to them has been experienced in numerous states with different fuel companies so it is not an isolated incident witnessed by the private conversations I have had with others. I am out of pocket a good deal of time and shipping costs for samples and am now done with this.

"If there was a real problem with this we would have heard about it by now" is one of the reply's. "Well damn it, you just did with multiple incidents from numerous states with a good deal of the foot work already done for you" is my final reply to the situation.

The SAE spec as told to me by the Gates engineers allows for up to 50% swelling of the R7 spec hose under lab conditions. I did not see that amount but I did witness an alarming amount that is not right in my opinion.

As a general rule I do not beat my head against the wall because it feels good when I stop, I will let this issue drop. I do not feel Gates has a problem with their product as I see it happening to numerous makes of hose in the recent past. I believe the fuel companies are cracking their mixtures and they are now too aggressive for the hose currently on the market. Be warned and watch the fuel hoses closely as I saw things I considered alarming.

Dave

 

I've never had a problem draing the tanks. As long as you can get the car in the air and have a five gallon bucket available, it is pretty easy. I do try to get the tanks as low on fuel as possible. And making sure there is no kind of spark available anywhere is a must. I do find that most of the excess gas gets on me rrather than the floor.

 

I have only done fuel filters so far but I agree that it seems only me gets drenched in gas. And I have not gone out in a blaze of glory. At least, not yet .

Seamus

P.S. I wish I could drain coolant and fuel without making a mess! (Well, except for my motorcycle where it seems much easier to contain the fuel when replacing lines etc.)

 

Coolant always seems to be the bigger mess (slippery, no evaporation, always seems to get everywhere when it runs out). I fill a mop bucket and just keep mopping until the floor stays dry.