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Mikez73

Webers leaking

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I have a similar issue with my Mikunis, especially upon cold start in sub 50 temps. Once warmed up and on warmer days, no issue at all. I think my problem is that I use no choke and may be slightly flooding when starting.

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Looks like you have the plastic spacers between the carbs and the intake. When the O-Rings in the spacers lose their elasticity, they leak. Eventually you will have a vacuum leak as well, if you don't yet. If the covers are leaking you can just buy a gasket kit for the carbs. It's not that hard to open them up and change gaskets. I bought a bunch of O-rings from Mcmaster and can sell you a set of them if they are the same as the ones in my Weber plastic spacers. Cheap. I have a ton of them.

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Almost looks like you need new gaskets on the top plates. That's what mine needed when it leaked like that.

Dave

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I have a similar issue with my Mikunis, especially upon cold start in sub 50 temps. Once warmed up and on warmer days, no issue at all. I think my problem is that I use no choke and may be slightly flooding when starting.
If we're lucky those sub 50 degree days are over for awhile. My car is a PITA to start. I know about the starter circuits on the Webers now but I need to find a way to connect them. I've read that they don't do much though.

Seems to be a lot of Z cars running around out there in the Woodlands area.

Looks like you have the plastic spacers between the carbs and the intake. When the O-Rings in the spacers lose their elasticity, they leak. Eventually you will have a vacuum leak as well, if you don't yet. If the covers are leaking you can just buy a gasket kit for the carbs. It's not that hard to open them up and change gaskets. I bought a bunch of O-rings from Mcmaster and can sell you a set of them if they are the same as the ones in my Weber plastic spacers. Cheap. I have a ton of them.

That would be great. I didn't know there were o-rings in there. I understand why the o-rings are used instead of gaskets after reading Nigel1943's response.

Almost looks like you need new gaskets on the top plates. That's what mine needed when it leaked like that.

Dave

That wouldn't surprise me at all. They do have some staining and residue on top. I probably need to look for a gasket kit.

Right now I'm focused on that ignition problem and rust hunting ;) There isn't much rust on the car but it's like finding out there are spiders in the car...I won't be comfortable until I find every spot of rust and kill it.

A 240z might have been a bad choice for me...

The outer (Thackery) washers look a tad too tight. They are designed to allow flexibility in the carb mounting.

I had to google Thackery washers and what they do after reading your post. Thanks for the tip. They probably are overtightened because I tightened the nuts a little thinking I might stop the leak. Hope I didn't damage them.

Edited by Mikez73

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You have the car sitting a long time ? Your gas seems really ''varnishy'' , almost like a cherry colored stain ! I would rebuild the carbs and clean out the system as well . Or , did you use a (lot) of gas stabilizer ? :)

Edited by Unkle

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You have the car sitting a long time ? Your gas seems really ''varnishy'' , almost like a cherry colored stain ! I would rebuild the carbs and clean out the system as well . Or , did you use a (lot) of gas stabilizer ? :)

Yeah it is very dark isn't it. The PO didn't drive it much. I just bought the car in November and I haven't driven it much either. The car is probably wasted on me. It's a great little car but it should be with an owner that could give it more attention. Some new gaskets might be in order but the carbs work great once the engine is warm.

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I have a similar issue with my Mikunis, especially upon cold start in sub 50 temps. Once warmed up and on warmer days, no issue at all. I think my problem is that I use no choke and may be slightly flooding when starting.

Hope you're still watching this thread Frank. When your carbs leak, does the gas come out through the air horns and leak through the filter? I was working on the ignition tonight so the key was on and the fuel pump was running. I noticed a strong gas smell so I checked under the carbs and the bottoms of the filters were soaked with gas. I need to find the fuel pump fuse so I can pull it while I'm trying to get the ignition sorted out but I was thinking that in the future maybe the carbs need a return line. What do you think? There is a capped off smaller hard line running along side the larger fuel supply hard line. I'm guessing that was the original return line before the Webers were installed.

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Webers like a low fuel pressure - like 3.5 or less. I installed a FPR and set it 3lbs and my leaking through the air horns on installation stopped. Ran my 40dcoe's like that for nearly 15 years. Added a return line when I got to Houston which really made no difference.

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#9. If you're leaking gas with just the fuel pump running, you've got more than just a return line issue. I capped my return line and haven't had any problems at all, aside from the aforementioned start-up issue.

Sounds like you've got a few leaky gaskets, 'cause once the float bowls fill, the float should stop all gas flow. If your pump is putting out an excessive amount of pressure that could be the culprit as well. As oldhemi noted, Webers (and Mikunis) require around 3 - 5 PSI. Any more than that and stuff just doesn't work as well.

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#9. If you're leaking gas with just the fuel pump running, you've got more than just a return line issue. I capped my return line and haven't had any problems at all, aside from the aforementioned start-up issue.

Sounds like you've got a few leaky gaskets, 'cause once the float bowls fill, the float should stop all gas flow. If your pump is putting out an excessive amount of pressure that could be the culprit as well. As oldhemi noted, Webers (and Mikunis) require around 3 - 5 PSI. Any more than that and stuff just doesn't work as well.

I'll see about getting a Holley FPR later. I was thinking about this one but it doesn't have a gauge port. My pump is supposed to be recommended for Weber carbs.

How hard is it to install a gasket kit on the Webers?

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Webers like a low fuel pressure - like 3.5 or less. I installed a FPR and set it 3lbs and my leaking through the air horns on installation stopped. Ran my 40dcoe's like that for nearly 15 years. Added a return line when I got to Houston which really made no difference.

I checked the box of old parts the PO sent along with the car. He had installed a new pump just before I got the car. I assumed it was a Carter low pressure pump. There is a Carquest E8012S fuel pump box containing the old pump so I'm assuming that the Carquest pump is what he had installed. The specs on that pump are 5-9 psi @ 75-100 LPH. In light of that info I think I'll go ahead and install an FPR and set the pressure at 3psi.

I'm going to use a Holley 12-804 1-4psi FPR and add an inline gauge. Sound okay?

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Sounds like a plan. If you want to go cheap and fast, you could use a cheapy from a local parts store. However, it would be cool to have one with a pressure gauge provision. But, I see a lot of posts where guys are not happy with the gauge. Mine looks like very much like this one:

http://www.amazon.com/Spectre-2517-Chrome-Pressure-Regulator/dp/B000CQ46H0

You mentioned gaskets earlier. You could easily remove the 5 screws on the top of your carbs and very gingerly remove the top taking care that the gasket does not tear to take a look at the floats. There is a large gasket that covers the whole carb body between the cover and the body. To replace this gasket, you must remove the floats. To remove the floats, you have to remove the pin. This pin removal is a bitch. I broke one of the "towers" cast in the top cover. Turns out that this problem is not uncommon. I have not replaced the top yet because the other tower grips the pin very tightly and I can get by for now.

I would suggest that if your carbs are not leaking around the tops, to reconsider replacing gaskets. This gasket not only seals to the outside of the carb, but also seals some innard chambers. If your carbs are leaking around this gasket, then you might have a float adjustment issue or a leaking float problem.

Edited by oldhemi

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Sounds like a plan. If you want to go cheap and fast, you could use a cheapy from a local parts store. However, it would be cool to have one with a pressure gauge provision. But, I see a lot of posts where guys are not happy with the gauge. Mine looks like very much like this one:

http://www.amazon.com/Spectre-2517-Chrome-Pressure-Regulator/dp/B000CQ46H0

You mentioned gaskets earlier. You could easily remove the 5 screws on the top of your carbs and very gingerly remove the top taking care that the gasket does not tear to take a look at the floats. There is a large gasket that covers the whole carb body between the cover and the body. To replace this gasket, you must remove the floats. To remove the floats, you have to remove the pin. This pin removal is a bitch. I broke one of the "towers" cast in the top cover. Turns out that this problem is not uncommon. I have not replaced the top yet because the other tower grips the pin very tightly and I can get by for now.

I would suggest that if your carbs are not leaking around the tops, to reconsider replacing gaskets. This gasket not only seals to the outside of the carb, but also seals some innard chambers. If your carbs are leaking around this gasket, then you might have a float adjustment issue or a leaking float problem.

I went ahead and ordered the Holley from Summit. It was only 5 or 6 bux more than the Spectre. Should be here tomorrow. I'm not sure where I'll mount it. I'd like to redo the line to run in back of the motor but that would mean rearranging the fuel inlets on the carbs.

I got the new spacers and o-rings on. I'm hoping I got the thackeray washers right. It's damned near impossible to see the bottom mounts or get a feeler gauge in there.

There is definitely gas coming out of one of the horns on the last two carbs.

That sounds like info a Weber expert could hear and say "yeah I know what the problem is" :)

I found a shop in the UK that has good rebuild kits w/ gaskets , O rings, filters, needle valves and seals for $30 per carb. It's isn't in the budget right now though.

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Have you looked in your message inbox yet ? as i have sent you a message concerning your car a couple days ago.

I don't have any new messages. If you are in the UK I think we'd have a hard time working out a deal. Thanks though.

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I got the Holley FPR in today. Geez that thing looks so cheap compared to the Aeromotive FPR I had on my shiro. But then it cost much less less than the Aeromotive.

There really isn't a good place to install it.

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I installed that Holley 12-804 FPR today. Seems like junk. It has no effect on fuel pressure at all.

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Mike, the mechanical fuel pump will do the job, so leave that fuse out for now.

I think it's a good decision to rebuild those carbys, ordering from Matt / Eurocarbs, will make you sure to get genuene Dellorto / Weber parts, for Weber parts there is also fastroadcars.

When you have those carbs on fresh and rebuild, do like this: http://www.classiczcars.com/forums/showpost.php?p=325940&postcount=35

Look in your inbox, ive send you a PM and no, i'm not trying to buy your car :D

Chris

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There is no mechanical fuel pump on my car Chris. Matt is cool. Great prices too on ebay. I bought some spacers and thackeray washers from him awhile back. I would have bought the cosworth washers but I didn't know about them at the time.

That's a good post. I've been watching that thread. I'll check the PM. I wouldn't mind that much if somebody did buy my car. I'd kinda like to get back to efi and turbochargers.

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One thing I didn't mention in that other thread is that I hated to mess with the carbs because aside from the leaking they seem to be adjusted very well. Once the motor warmed up it ran great. No hesitation, stumbles or flat spots and the idle was good.

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Well if your jetting is good, i don't see it as a big problem, the hardest parts is to get that jetting correct, other than that it is just balancing and idle mixture, but you need to get your timing fixed first.

Chris

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One of you guys may be able to help me out with the way the fuel line is routed. Where the fuel supply and return lines end on the passenger side, there is a hose connected to a hard line that runs around the front of the radiator core support to the drivers side where another hose is run to a fuel filter and on to the carbs.

Is this the way Nissan ran the fuel lines or did the guy who install the Webers run this line? Seems kind of risky in a front end collision.

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