Questions about Installing new gaskets on Weber IDA’s

[Derek77]

Hey Guys,

I’m replacing all the gaskets on my Weber’s and this is first of probably many questions.

I was testing the output of each accelerator pump jet and noticed two of them were seeping a little fuel onto the top of the carb body. Not a lot but enough to make the top of the body moist. Is this normal? I replaced the copper gaskets related to the pump jets. My whole goal of installing the new gaskets is to stop the seeping I was getting so I’m going to be pretty frustrated if I still have seeping after replacing all the gaskets. Can anyone help guide me? Below are a couple of pictures and I’m referring to item 70 on diagram.

Thank you,

Derek

[juanbenae]

so if im following you they are still seeping even after the new copper crush washer was installed?

how did the threads on the jet and seat look?

[1QuickS]

Imperfect seat on the carb or on the bottom of the squirter nozzle will allow fuel to weep. You can probably see the issue once you have a close look at the areas of concern. The bottom of the squirter nozzle can be re-surfaced over the edge of a block with 220 grit sandpaper, nozzle hangs over the edge so you can sand the sealing surface on the block. The seat in the top of the throttle body is more difficult but if you have a drill press you can get a flat end mill from McMaster-Carr and re-cut the interface but do so with hand power.

[Derek77]

Originally Posted by juanbenae

so if im following you they are still seeping even after the new copper crush washer was installed?

Unfortunately, yes Sir.


how did the threads on the jet and seat look?

Threads looked good but after reading Paul’s advice below I took closer look. Neither surface looked great as you can see.

[Derek77]

Originally Posted by 1QuickS

Imperfect seat on the carb or on the bottom of the squirter nozzle will allow fuel to weep. You can probably see the issue once you have a close look at the areas of concern. The bottom of the squirter nozzle can be re-surfaced over the edge of a block with 220 grit sandpaper, nozzle hangs over the edge so you can sand the sealing surface on the block. The seat in the top of the throttle body is more difficult but if you have a drill press you can get a flat end mill from McMaster-Carr and re-cut the interface but do so with hand power.

Hi Paul,

Thank you for chiming in. I have read all your notes on your website and I would have sent these to you if you were accepting work prior to 2020. It’s probably for my own good as I need to learn how these work. I polished the jet as you recommend and it looks much better. I’m going to have to study up on doing the body as I don’t have a tool that will do that properly right now. Thank you so much for all your contributions to the 911 community, it’s appreciated by many.

Derek

[Derek77]

Another area I had issues was the fuel supply bolts and the float needle valve caps. Upon closer inspection one of my bolts has a slight high spot on the sealing surface and one cap has what looks like corrosion around the sealing edge. Not sure if these can be fixed or should I order new? Probably difficult to see in these pictures.

[juanbenae]

I might try some fine steel wool on the cap to see if you can remove the crud.

the fuel supply bolt as you recognize are significantly sized so maybe the flat surface of a sharpening stone could knock it down some? I would expect the FSB crush washer to be of the same material as the other crushes so considering they are soft enough to seal other bits at minimal torque one might think with the larger bolt and torque the crush would take up some unevenness.


plus, you can't get just one new FSB it would look funny being so bright compared to the old tarnished ones... im not sure what they cost, but I am sure santa can't bring them on such short notice... do you have weber or PMO fuel rails?

what's the harm in trying it if you are prepared to buy new anyway? the FSB are so accessible if one or more end up sweating they can be quickly swapped out at a later time if needed.

on another note regarding carb body paper gaskets. I was wondering what paul's take is on applying WD-40 to them prior to install? ive forever always spray down any automotive gasket 10-15 minutes before install to swoll and keep them from sticking in the coming years when removed.

[Derek77]

Originally Posted by juanbenae

I might try some fine steel wool on the cap to see if you can remove the crud. Juan, thank you for the suggestions. I’ll try the steel wool.

the fuel supply bolt as you recognize are significantly sized so maybe the flat surface of a sharpening stone could knock it down some? I would expect the FSB crush washer to be of the same material as the other crushes so considering they are soft enough to seal other bits at minimal torque one might think with the larger bolt and torque the crush would take up some unevenness. I haven’t tested the fuel supply bolt or cap since replacing the gaskets. I might be worrying about nothing. I like the sharpening stone idea.


plus, you can't get just one new FSB it would look funny being so bright compared to the old tarnished ones... im not sure what they cost, but I am sure santa can't bring them on such short notice... do you have weber or PMO fuel rails?
Haha yeah, mine is not a cosmetic project for sure. Purely functional, heck that describes my whole car. I’ve got budget constraints and my goal is a reliable fun to drive car, not a show car. I have Weber rails.

what's the harm in trying it if you are prepared to buy new anyway? the FSB are so accessible if one or more end up sweating they can be quickly swapped out at a later time if needed. This is a really good point. Sometimes I obsess over things rather than just giving it a try. It’s like you know me or something. Haha

on another note regarding carb body paper gaskets. I was wondering what paul's take is on applying WD-40 to them prior to install? ive forever always spray down any automotive gasket 10-15 minutes before install to swoll and keep them from sticking in the coming years when removed.

I’m new to working on 911’s and would like to hear Paul’s take on this. I wonder how often one needs to replace gaskets on Weber’s? The PO went through my carbs but that was about 10 years ago. I didn’t have any major gasket sticking issues only minor.

Thanks Juan!

[juanbenae]

we carb guys gotta stick together derek… if not familiar with paul's site,,,, well shame on you..

Performance Oriented

[1QuickS]

In my work I have found that re-machning the interface on the top cover where the brass hex cap covers the fuel needle valve (quite a long chain of descriptives...words ARE hard, aren't they?) plus re-surfacing the sealing surface on the underside of the hex caps will provide a routinely good seal against leakage. Also needing attention is the interfaces around the banjo bolts but there (I have found) the issue for sealing tends to be the hard & dimpled gasket between the banjo fitting & the top cover. I sand the gasket for this interface to remove the dimples from its surface plus sanding the banjo interfaces just to be complete.

I use a special tool to sand the hex cap surfaces to remove deformations but a careful search for a large, flat washer that allows the threads to pass through and then a piece of sandpaper that has an appropriate hole will provide an adequate, circular surface to sand the blemishes away. Easy to do.

I think that most metallic gaskets are good to reuse but accelerator pump gaskets (diaphragms) can get old and I think updating them is good. As for the sealing issues: the top covers are always distorted from tightening the four securing nuts and thereby have a non-flat sealing surface between the nuts. Agin, sandpaper and a flat surface is your friend, easier if you press the tip of the fulcrum pin in the top cover & then drive it out with a rod to allow easy sanding. f not pressed during the initial 1/8" of movement you risk mushrooming the tip & causing more difficulty during removal.

[Derek77]

Originally Posted by 1QuickS

In my work I have found that re-machning the interface on the top cover where the brass hex cap covers the fuel needle valve (quite a long chain of descriptives...words ARE hard, aren't they?) plus re-surfacing the sealing surface on the underside of the hex caps will provide a routinely good seal against leakage. Also needing attention is the interfaces around the banjo bolts but there (I have found) the issue for sealing tends to be the hard & dimpled gasket between the banjo fitting & the top cover. I sand the gasket for this interface to remove the dimples from its surface plus sanding the banjo interfaces just to be complete.

I use a special tool to sand the hex cap surfaces to remove deformations but a careful search for a large, flat washer that allows the threads to pass through and then a piece of sandpaper that has an appropriate hole will provide an adequate, circular surface to sand the blemishes away. Easy to do.

I think that most metallic gaskets are good to reuse but accelerator pump gaskets (diaphragms) can get old and I think updating them is good. As for the sealing issues: the top covers are always distorted from tightening the four securing nuts and thereby have a non-flat sealing surface between the nuts. Agin, sandpaper and a flat surface is your friend, easier if you press the tip of the fulcrum pin in the top cover & then drive it out with a rod to allow easy sanding. f not pressed during the initial 1/8" of movement you risk mushrooming the tip & causing more difficulty during removal.

Paul, this is awesome information, thank you! Where can I find torque settings for various fittings, nuts, etc? Only one I’ve located is bodies to manifolds at 8-10 ft lbs. I have an inch pound torque wrench so can do low values.

Dang, I already replaced all accelerator pump gaskets without checking covers for distortion. Guess I’ll take them apart again and check.

Thank you!

Derek

[Derek77]

Originally Posted by juanbenae

we carb guys gotta stick together derek… if not familiar with paul's site,,,, well shame on you..

Performance Oriented

JB,
I’ve been on Paul’s website so much my wife is getting Jealous. Thanks for the tip though and stick with me till I get running again. I haven’t had my own car since 1999 and have wanted a 911 for over 30 years. I finally achieved that goal.
Derek

[1QuickS]

I tend to torque by this method:

• Hex bolts: Tighten until definitely "in contact" & then "one flat" of rotation which is 1/6 of a turn
• Slotted screws: Tighten until definitely seated, loosen and then go to definitely "in contact" & then twist so that the screwdriver slot is advanced the width of the slot at the diameter of the head of the screw
• 8mm hex nuts for top covers: tighten in criss-cross pattern starting from center nuts until "just in contact" and then repeat with 1/6 turn from inner nuts toward the outer ones

[911pcars]

FWIW, without a good banjo sealing washer (Al or paper-type), I applied some Loktite 574 (engine sealant), an anearobic sealant, on the existing washer surfaces, then allowed it to cure overnight. Seems to work fine (IOW, no leakage).

Sherwood