Hello I am having a new-to-me problem with my carb's. The rear carb (B18D) float bowl cover has sprung a leak so to speak. Where the fuel enters the cover about 3/8 of an inch lower there is a hole(vent I assume) that the fuel has started to flow out of strongly. Previous to this starting I had removed both floats and cleaned the needles and seats(with carb cleaner and compresed air) due to a sticking needle. With finger pressure the needle seams to seat. At this time I also removed the sludge at the bottom of the float-bowls. What did I do wrong? Any thoughts?

Obviously, the float valve ain't sealing well... You mention that it seals if you put your finger on it... Thats more pressure than the valve will ever see.

If you take the float cover off, float still attached, you should be able to turn it upside down, and just the weight of the float itself pressing on the valve should seal it enough that you can't blow through it.

First thing to do though... when it leaks next time, give that float cover a few soft taps with a hammer or wrench or rock.. that usually cures the problem at least temporarily. I have to beat on the carbs in my Jaguar every morning before I take her for a spin... Just its way of asking for a little attention.

-Matt

Thanks for the imput. Yes the needle does not seat(rubber hard), Luckely I have a local English parts store(don't tell him it's going on a Volvo and he is polite, if he thinks it's for a volvo he is obnoctuous) he sold me new valves that he sais are superior to the old style, calls them grose valves, they use a ball instesd of the needle and seat, looks neat, works fine.

Merci

Yvan
--
65 122, 73 P1800ES, 79 242GT, 80 262C, 81 242, 87 780,88 745T X2, and a plethora of parts cars and eventually to be finished projects

Actually, I think the 'gross jets' are the original type.. the later ones having the rubber seal probably because they are cheaper to make. SU is making the original type again, and I also think they tend to work better. Still can get dirty though.

-Matt
--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

Grose Jets are an aftermarket item. They do not like any imperfection on the float "tang" that pushes on them so get a new float too.

Mike!

Oh... and as suggested, definitely be sure you ahve a filter twixt the pump and the carbs. A tiny bit of dirt or rust from the tank will cause your problem every time.

A friend of mine had a freshly restored old Jag...much, much nicer than mine will ever be, and the carbs leaked miserably. Turned out that his fancy new custom made aluminium petrol tank still had a bunch of metal shavings inside... what a mess when them shavings made their way to the floats...

-Matt

Too bad he didn't have a nonstock off-the-shelf filter in there
(or did I mean philtre.....?)
--
George Downs, Bartlesville, Oklahoma, Central US

Of course I use both a pre and post pump filtre(french spelling of the english philtre, same pronounciation I think).

Merci

Yvan
--
65 122, 73 P1800ES, 79 242GT, 80 262C, 81 242, 87 780,88 745T X2, and a plethora of parts cars and eventually to be finished projects

We put one in that day... $1.50 filter in a $50k+ car, but it got us to the bar. Brakes failed on teh way home... me driving of course.

Yes, I think 'philtre' is what they call 'em over yonder across the pond....

-Matt
--
-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

syvas;

...sounds like a nonseating bowl valve...remove bowl cover, blow out, and inspect valve including float level, do you have a post pump filter installed?

Cheers

Thanks for the imput. Yes the needle does not seat(rubber hard), Luckely I have a local English parts store(don't tell him it's going on a Volvo and he is polite, if he thinks it's for a volvo he is obnoctuous) he sold me new valves that he sais are superior to the old style, calls them grose valves, they use a ball instesd of the needle and seat, looks neat, works fine.

Merci

Yvan
--
65 122, 73 P1800ES, 79 242GT, 80 262C, 81 242, 87 780,88 745T X2, and a plethora of parts cars and eventually to be finished projects

Thanks for the imput. Yes the needle does not seat(rubber hard), Luckely I have a local English parts store(don't tell him it's going on a Volvo and he is polite, if he thinks it's for a volvo he is obnoctuous) he sold me new valves that he sais are superior to the old style, calls them grose valves, they use a ball instesd of the needle and seat, looks neat, works fine.

Merci

Yvan
--
65 122, 73 P1800ES, 79 242GT, 80 262C, 81 242, 87 780,88 745T X2, and a plethora of parts cars and eventually to be finished projects

Float level set correctly?

Are the needles rubber (viton) tipped ends still flexible?

Dried up fuel hose with loose or missing clamp connecting the fuel bowls (I had this happen and it looked like a leak out of the rear bowl vent).

Cheers

Thanks for the imput. Yes the needle does not seat(rubber hard), Luckely I have a local English parts store(don't tell him it's going on a Volvo and he is polite, if he thinks it's for a volvo he is obnoctuous) he sold me new valves that he sais are superior to the old style, calls them grose valves, they use a ball instesd of the needle and seat, looks neat, works fine.

Merci

Yvan
--
65 122, 73 P1800ES, 79 242GT, 80 262C, 81 242, 87 780,88 745T X2, and a plethora of parts cars and eventually to be finished projects

Your float valve is not closing completely.
If it is a neoprene tip valve, carb cleaner can injure it.
--
George Downs, Bartlesville, Oklahoma, Central US

Thanks for the imput. Yes the needle does not seat(rubber hard), Luckely I have a local English parts store(don't tell him it's going on a Volvo and he is polite, if he thinks it's for a volvo he is obnoctuous) he sold me new valves that he sais are superior to the old style, calls them grose valves, they use a ball instesd of the needle and seat, looks neat, works fine.

Merci

Yvan
--
65 122, 73 P1800ES, 79 242GT, 80 262C, 81 242, 87 780,88 745T X2, and a plethora of parts cars and eventually to be finished projects

I used Grose Jets for some time but began having more and more trouble with
them and have gone back to conventional float valves. This has been on both
HS6 and HIF6 carbs.
--
George Downs, Bartlesville, Oklahoma, Central US

Ditto... Grose jets have been perfect on Webers (both down- and side-draft), but I took them back out of the last set of SUs I tried them in. They wanted to stick closed, even on a clean system with a good filter. I have no explanation why that was, but that's been my experience.

Hi. Goose Jets are used also on the carbs of some old military trucks (on use here by our army). It need at least 3 lbs of pressure on the fuel line to work (army mechanics discover it the hard way, as a retired one tell me).

If I remember right, I read on some manual than the original valves on our carbs work on 2-4 lbs. And with the pass of the time a tired pump make a bit less pressure...I suggest to check the fuel line pressure before install goose jets.

Joaquin
Rojo 121 Amazon
Lima Peru

Cleanliness shouldn't be too much of a problem as I use only premium gas, which contains a fuel system cleaner. Also I regularly add a octain boost/lead substitute/cleaner. Of course I use both a pre and post pump filtre(french spelling of the english philtre, same pronounciation I think).

Merci

Yvan
--
65 122, 73 P1800ES, 79 242GT, 80 262C, 81 242, 87 780,88 745T X2, and a plethora of parts cars and eventually to be finished projects