Carb Fuel Leak - Need Some Help

Need some expert help/advise...

Posted a question on @Robert M thread on his recent engine project, but I think I’ve narrowed down where my fuel leak is coming from. I clean the idle jets and mains. Still leaks...

I took a pic of where I believe the leak is coming from. There is a light silver circle in the section where the fuel line connects to the carb right above and center of the idle jets.

What does it do? Am I screwed if it leaks from that spot?

It looks like a plug of some sorts...

Yes, they are EMPI HPMX 44 carbs and I don’t care to hear “brand” comments.

Thanks in advance for the help my madness family!

B

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Those are called carb expansion plugs.  Guess from when the carb body was cast.  I'd try to tap with a drift pin (Flat punch slightly smaller than plug).  When installed they are slightly convex and the drift pin flattens them out to fill the hole.  Wonder if JB Weld would stick and seal (clean well first)?

I figured it was some plug to tap a hole of sorts. The passenger side carb had a tiny residual of fuel too. On the driver side... it was visibly dripping when I had the engine running...

Damn... I guess I shouldn't get too mad since I can't remember the last time I had an issue with my Speedster... she's been good to me...

I'll reach out to @VSpyder and see what we can do. I have <2500 miles on them. Manufacture defect? This would be the second time I've had a problem with these carbs. Maybe Greg has a better route/plan.

Thanks @WOLFGANG

Alan Merklin posted:

Hopefully you can seal it ( ask Greg on his experiences) One option is to drill and tap it for a plug. Just be careful whatever your choice is, that it is  done in a craftsman like manner, engine fires can ruin your day.

Thanks Doc! Would love to see if there is some sort of manufacture warranty before having to drill into these things...

WOLFGANG posted:

Those are called carb expansion plugs.  Guess from when the carb body was cast.  I'd try to tap with a drift pin (Flat punch slightly smaller than plug).  When installed they are slightly convex and the drift pin flattens them out to fill the hole.  Wonder if JB Weld would stick and seal (clean well first)?

I once "fixed" a pin hole in the fuel tank of a type I with JB Weld.

@*LongFella  B-

i had the same problem with HPMX CARBS IN 2016 and 2017.  I first tried the JB weld repair... then in parallel contacted Empi customer service.  They stepped up and sent me replacement top cover at no cost... twice, but I lost confidence in the carbs after the second failure ( ref 2017 incident and pics), and purchased Webber’s from Pat D. At CBP.  Other than this, the carbs worked great.

full story line, with pictures below;

2016-  https://www.speedsterowners.co...1#497688234564864801

2017-  https://www.speedsterowners.co...2#565106356525552742

happy to send you the EMPI  CAliformania support # and email if you don’t have it.  I can dig it up...

Cheers,

Luis,

Robert M posted:

I knew someone else had gone through this, I just couldn’t find the links. Thank you Luis. 

And that is why this forum and all you maddening people are awesome!

Thank you @Lfepardo ! !

I’ll try connecting with Greg. I know he has a contact at EMPI he works directly with. They had to swap out one before because the housing casting had a hairline crack.

Knowing you’ve been through this twice... maybe it’s time for an upgrade...

I've done a repair on a similar problem that may be applicable.....   Prep, cleanliness, and patience are the key factors ......    I had a fuel leak on a rice burner that would require massive amounts of cubic rectangular green to repair at the dealer service dept......   The carb had a "pin hole" in it's top cover......  

I lightly sandedthe area. (220 grit) Cleaned it with lacquer thinner. Rinsed it with alcohol, twice.    Then applied Dow Corning Silicone rubber to the area.  waited 48hrs. for the cure and drove the vehicle 90,000+ miles....

Today, a really good option might be one of the silicone gasket cements.....

Just a thought....

Had a good convo with Greg on my drive home after work last night. We have a plan! Unfortunately, I am beyond any full carb replacement warranty but there are a few fixes we can do to get them leak free.... and of course Greg will help out without charging me... plus... it gives me an excuse to stop by his shop and see on the cool projects he has going

Decided to take a stab at the repair myself. If I fail, I’ll go the Weber route. Figured I need to learn more about carbs and how to fix/clean/handle them...

- Drilled a tiny hole in the plug and pulled it out

- Cleaned the cr@“ out of it (carb cleaner and compressed air)

- Used my metric tap/die set to make nice 6mmx1.0 threads

- Cleaned the c&@ out of it (carb cleaner and compressed air)

- Placed 6mm hex plugs with gasket forming (gasoline resistant) stuff on the plug threads before screwing it in nice and tight

- Once cured conpletely (24hrs), I’ll clean everything again and put it all back together.

I’ll do the other side tomorrow. And since I’m working on the carbs, I’ll add the hex head idle jet holders I’ve had for about a year in my cabinet and the Jet Doctors...

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Well done, Brian. What's really too bad is that we have to put up with poor quality like this at all; if the majority of the VW crowd wasn't so cheap *ssed, companies like EMPI wouldn't get away with putting out crap like this and would have to turn out products that worked as intended and lasted more than a few thousand miles. It kills me to watch people on the Samba, time and time again buying something from EMPI (the other was too expensive- I wouldn't pay that!) and then when it fails, buy exactly the same thing again expecting a different result! If they'd bought the properly made piece they'd ultimately have money in their pocket (and let's not even consider the wasted hours). 

Time to get off my soap box (again) and go back to bed (it's still early here on the Wet Coast). Yoda out (but back...ahhh, you know the rest!)

I have yet to receive a new carb from anyone and have the floats set correctly right out of the box.  Not Weber, not Dellorto, not Holly, not Carter/Autolite, not anybody.  Always have to set them up.  If somebody built that engine and just pulled the carbs from the box and installed them, well.....   That’s what’cha got.

Follow the book, take your time and you WILL be rewarded for your effort.  

Nice job on the plug, too!

Gordon Nichols posted:

I have yet to receive a new carb from anyone and have the floats set correctly right out of the box.  Not Weber, not Dellorto, not Holly, not Carter/Autolite, not anybody.  Always have to set them up.  If somebody built that engine and just pulled the carbs from the box and installed them, well.....   That’s what’cha got.

Follow the book, take your time and you WILL be rewarded for your effort.  

Nice job on the plug, too!

I finished both carbs yesterday. Surprisingly, working on the carbs is not that complicated. If I ever decide to get into learning about "jetting" - I think that is where it will get complicated and too confusing...

The passenger side carb float was WAAAYYY off. It was like 15mm seated. Should be able to get it all back together this week and see if my efforts stopped the fuel leak...

@*LongFella wrote- "Surprisingly, working on the carbs is not that complicated. If I ever decide to get into learning about "jetting" - I think that is where it will get complicated and too confusing..."

The key to sorting out jetting, Brian, is to realize it's not all that hard, approach it methodically and only make 1 change at a time. It's a bit of a time consuming process, as you change a jet 1 step (up or down, depending on what you're doing), put it back together, drive it for a little bit and then re-assess. It does take a while, but it's surprising how close to optimal you can get without a wideband air/fuel meter.

Resist the temptation to play with the mains/airs and only work on the idle circuit first. John C (Aircooled.net) actually recommends taking out the main jet stacks so you're only driving on the idle circuit. Usually the idles are pig rich (even "jetted for you" carbs will come rich), so you start out very simply- putting in smaller idle jets until it starts to run rough, and then going back up 1 so it runs smoothly. When you're ready I can direct you to some good write ups. IIrc Danny P has put some great dual carb info (rebuilding as well as jetting, I think) in the knowledge base. Some more reading- Aircooled.net's technical articles. Al

http://www.aircooled.net/how-t...t-up-vw-carburetors/

http://www.aircooled.net/synch...-vw-carburetors-103/

http://www.aircooled.net/vw-carburetors-jetting-102/

Here they are- don't read them all at once!

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