Mikez73 Posted March 4, 2010 Share #1 Posted March 4, 2010 Looks like it. Looks like more than a simple gasket is required. Link to comment Share on other sites More sharing options...
d240zx2 Posted March 4, 2010 Share #2 Posted March 4, 2010 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. Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 4, 2010 Share #3 Posted March 4, 2010 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. Link to comment Share on other sites More sharing options...
Zs-ondabrain Posted March 4, 2010 Share #4 Posted March 4, 2010 Almost looks like you need new gaskets on the top plates. That's what mine needed when it leaked like that.Dave Link to comment Share on other sites More sharing options...
Nigel1943 Posted March 4, 2010 Share #5 Posted March 4, 2010 The outer (Thackery) washers look a tad too tight. They are designed to allow flexability in the carb mounting. Link to comment Share on other sites More sharing options...
Mikez73 Posted March 4, 2010 Author Share #6 Posted March 4, 2010 (edited) 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 March 4, 2010 by Mikez73 Link to comment Share on other sites More sharing options...
Unkle Posted March 4, 2010 Share #7 Posted March 4, 2010 (edited) 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 March 4, 2010 by Unkle Link to comment Share on other sites More sharing options...
Mikez73 Posted March 4, 2010 Author Share #8 Posted March 4, 2010 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. Link to comment Share on other sites More sharing options...
Mikez73 Posted March 6, 2010 Author Share #9 Posted March 6, 2010 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. Link to comment Share on other sites More sharing options...
oldhemi Posted March 6, 2010 Share #10 Posted March 6, 2010 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. Link to comment Share on other sites More sharing options...
d240zx2 Posted March 7, 2010 Share #11 Posted March 7, 2010 #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. Link to comment Share on other sites More sharing options...
Mikez73 Posted March 19, 2010 Author Share #12 Posted March 19, 2010 #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? Link to comment Share on other sites More sharing options...
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