Question about SU HS6's.
Ive been reading allot of threads about carbs types for the B20 that are built for more HP.
Basically what the end result is far more of you feel the HS6's are they way to go if they are fresh, tight and tuned accordingly with the proper settings and needles.
Currently my HS6's which were recently rebuilt by Chester Gillings in Colorado leak at the fuel bowl, will not tune worth a dam and have me considering buying a new set up (was thinking Mikuni) or maybe just a new set of HS6's.
Thoughts about what to do are greatly appreciated. Thanks

Cameron is right.
You should FIRST measure your fuel pressure with a pressure gauge that can tell
the difference between 2.5, 3.0 and 3.5 psi. 0-10 psi total range is probably good.
If the pressure is 3.0 or less the overflow would be because of faulty or loose float valve,
dirt in the valve or really bad float level setting. In that case you should probably go back to the rebuilder.

If your fuel pressure is OVER 3 psi, make sure that you have the proper spacer and 2 gaskets between your fuel pump and the place on the block where it mounts.
When you get the overflow problem solved, then you can set float levels and jet
levels
(mixture).
--
George Downs Bartlesville, Oklahoma

Thanks George, I know the gaskets and spacer are correct and I feel the fuel pressure is ok because the float bowls only leak once in a while which is leading me to think possibly dirt in the float area.
Your like the Brick Board guru aren't you? I see your replies everywhere. So your a Volvo Nut? This is my first Volvo and what attracted me was the lines of the car (122S). the car I bought is from Cali, very solid car no rust or rot. It seemed simple enough of a car to play with so I jumped right into a restoration, did some custom work to the interior and obviously modded up the drive line. I just took the car for a ride and its running better then before so im getting closer with all my adjustments. Thanks again. Bone

So you are in Colombia? (Cali)
Well, I've been driving Volvos since 1967 and 122s since 1970 so I have LOTS of experience,
some of it fairly disastrous. I get my kicks trying to help you guys stay out of trouble.
Lately my lungs have got me to where I can't do much but am hoping for an improvement
with a new doctor's appointment this Wednesday. Kind of an aggravation since I've been
a rabid anti-smoker my whole life! Got too many projects waiting to be laid up now!
--
George Downs Bartlesville, Oklahoma

Morning George, so sorry to know your projects are on hold and best of luck with the new Doc.
I'm actually on Long Island. I saw the 122 body when looking for a Volvo on eBay, thinking I was buying a XC type I saw a 122S and thought 'what is that????' and after about a month of researching and poking around I decided finding a solid car would be nice. After all driving what we want to aside from what we have too makes it more fun to do. I found my car in Bakersfield Cali, shipped it to NY, drove it for about 2 weeks before deciding to restore it. I spent most of the past 2 years waiting for parts from one particular supplier but in the end he came through. The car is just so dam pretty and bossy looking. Its light so it doesn't need a lot of power to her going quickly. Its simple enough front to back so working on it doesn't require a masters in Engineering. Parts are available all day long and I've bought many from eBay, California, Oregon, Sweden, the UK and the list goes on. I'm into my car now for about 21K and hoping the end is near. new suspension, wiring harness, motor, trans and conversion kit, paint and body work, new head liner and interior, it all adds up and until your done, your just not done.
I love my car but do not like the BS that comes with buying parts that are supposedly quality and you have to find out personally that they are not what they said they would be. My IPD header for example, simple to install and yet the alignment is an issue causing exhaust leaks at the head, pull it, adjust it, still leaks, pull it, clean all surfaces perfectly, install new gasket, still leaks. I cant deal with BS like that. I like to do a job, do it right and be done with it, same as most people. My carbs I can play with several times because I'm still learning how they work and the fundamentals of adjusting them. My 123 distributor has its moments of being awesome and then not so much.
I have to get out to work so Ill catch up later, enjoy the day. Bone

What issues are you having with the 123 ignition? I bought one, not installed yet, and would like to know what I'm in for.

The party that you referred to, that came thru in the end, is it the infamous JP?

HA, yes it is JP.
My ignition just doesn't seem to find a happy place to dwell, no pun. I can also tell you that in spite of that video that shows a smoother responding timing situation that is not my case here, when I shine my timing light on the crank pulley numbers it is all over the place but, that also may be because I'm having carb issues which apparently the distributor can detect but I don't see how.

I've installed two of the 123 distributors in Volvos, and each time, the timing marks jumped all over just as you describe. We found about a 20 degree variance at idle. Two different distributors, two different engines, about a year apart.

Removing the 123 and installing the original Bosch resulted in rock steady timing marks. Both times.

I reinstalled the 123 just to confirm that I hadn't lost my mind, both times, and the timing marks jumped all over the place. Also, the cars ran like crap, Both times.

The vendor asserted that the 123 was in perfect condition. Both times.

I'd try another 123 if someone gave it to me, but I wouldn't pay for one.

Actually, I'd happily pay full price for one AFTER it was installed in the car and operating as advertised. Which will never happen. I've never actually seen one in a car that was running, though I've heard from several people that they're fabulous. My own experience indicates that they're not at all fabulous.

Cameron
Rose City

hey Cameron, yeah I hear ya, I thought I was crazy too. Im not happy with my 123 BUT, lets not forget the slim possibility that this distributor does respond to the power output of the cylinders which means my carbs whish suck (no pun) need to be in perfect operating condition. Im going to post a thread about my 123 experience and see who else has similar thoughts, thanks for sharing that though because it helps me ease my own mental madness

It's a long shot that faulty fuel system issues would cause the ignition system to become faulty. You could have carbs that are fouling the plugs and leading to misfires that might seem like an ignition issue, but the root cause (in that instance) remains a fuel system issue. Weird fuel delivery problems cannot cause the ignition timing to jump around.

The rule of thumb when trying to make an engine run well is to first ensure that it has good compression - proper valve adjustment is part of this.

Second, ensure that the ignition system is working correctly. Sounds like yours is intermittent, which means it's not reliably correct. I'd address this first.

Last, deal with the carbs and get them dialed.

It can be really frustrating -- but trust me: if you've got an ignition problem and you're trying to get your carbs in order, you will very likely have to start over again with the carbs after you finally do address the ignition.

Good luck with it. Amazons are terrific cars when they're not arguing.

Cameron
Rose City

I get what your saying about the fuel system altering the ignition system, I was just stating the claim of the makers of the 123 being that the distributor can read what the engine power stroke is doping to determine the next firing sequence, sounds hokey to me but modern tech is pretty scarey at times too.

It might be better to carry this on offlist:
[username follows] gdowns [at] cableone [dot] net [nothing follows]
but I would say of all the vendors I have dealt with, IPD is close to the top
of the list as far as responsibility. Before you give up on them, call them up
and talk to one of their oldtimers and tell them what the probems are.
Maybe the header got bent in shipping or something. Normally they will stand
behind their stuff and send you a replacement guaranteed to fit, period.
When you talk to them, tell them a customer of theirs from the 1980s told you this
and feel free to mention my name.
--
George Downs Bartlesville, Oklahoma

I think you'll get more responses if your subject line matches your actual question. There are a lot more Volvo people who have experience with SU carbs than with Mikuni.

If your SU is leaking, either the float is damaged, incorrectly set, or you have a damaged needle and/or seat; or your fuel pressure is too high. That's about all it can be.

If the carbs won't tune worth a dam [sic], either they weren't properly rebuilt or whoever's trying to tune them is missing something. The Haynes isn't great but it does give a step by step rundown on how to go about getting them close. Lots of resources online, too, including some fun videos on youtube.

They're really simple things, but counterintuitive to those accustomed to other, more common carbs.

Best,

Cameron
Rose City

If the float bowls only leak once in a while, as you say, then it's probably dirt causing problems in the needle/seat area. Replacing the needle by one with a viton tip goes a long way in preventing these kind of issues. Do the bowls really leak both or is it only one?