BJ8 Carb leak

[Healey Nut]

So fellow BJ8rs .
I took the 67 out today of winter hibernation ...,.yeah I know I'm late ....it's a long story .
Anyways got back after a short trip and I can smell fuel a lot of fuel and its dripping underneath .
Further checks traced it to the base of the front carb and if the choke is on it's a lot more than just a drip it's a stream not something I want onto a hot exhaust . Car show next weekend in Hudson Quebec ,,
So is there a quick fix or am I pulling the whole carb off . Can I fix it from below (I have a hoist)
:eagerness::eagerness:

 

[BJ8Healeys]

Sounds like you have a tear in the diaphragm, Nut. You need to pull the front carb to fix it, and the rear carb to get access to the front carb.

 

[Patrick67BJ8]

Fuel can come from the needle/seat overflow tubes if the tubes are missing and run down the outside of the carb bowls to the underneath of the carb bodies. They sometimes get left off or lost over the years. There are two places for gas dripping or running as you described. If the gas is coming from the copper drain tubes attached to the intake manifold you have bad diaphragms as Steve said. If the gas is coming from the black plastic tubing( if you still have them installed on the overflow fittings on the carb float bowls), then it's a bad needle/seat.

I believe there's newer type of diaphragms available that last longer than the originals. I placed a piece of red tape on the end of the black plastic overflow tube for my Rear Carb so that I know which one has a bad needle/seat. If one diaphragm is bad/cracked, the other can't be far behind.

 

[Healey Nut]

Sounds like you have a tear in the diaphragm, Nut. You need to pull the front carb to fix it, and the rear carb to get access to the front carb.

Ive looked all over the exploded pic of a HS6 carb(in the Haynes manual)which is basically the same as a HD8 and there's no diaphragm in it ?
Am I missing something here ?

 

[Patrick67BJ8]

Ive looked all over the exploded pic of a HS6 carb(in the Haynes manual)which is basically the same as a HD8 and there's no diaphragm in it ?
Am I missing something here ?

Your post says BJ8 carbs and those are HD8's. They are like the HD6's but not the HS series carbs.

 

[Keoke]

Ive looked all over the exploded pic of a HS6 carb(in the Haynes manual)which is basically the same as a HD8 and there's no diaphragm in it ?
Am I missing something here ?

YEP:
HS6 Ain't like no HD8 ,
You have a failed diaphragm like Steve Byers told you .

Prolly should replace them in both carbs, prolly old as rain :wink-new:

Oh!! Yeah HN:
Some times the failure will be a small hole that can be detected only by looking into a bright light while stretching the diaphragm.

Sunshine worked for me.:highly_amused:

N: If the gas is coming from the copper drain tubes attached to the intake manifold they are simply doing what they were designed to do in case there is excess fuel being delivered.

 

[Healey Nut]

I'm just going from the quote in the Haynes manual that says they are basically the same so I assumed the components are the same . It says the only difference between the HS6 and HD8 is the overflow tube set up .
Does anyone have a link to an exploded view of the HD8 ?

 

[Keoke]

Sounds like you have a tear in the diaphragm, Nut. You need to pull the front carb to fix it, and the rear carb to get access to the front carb.

Well there is little trick you can use here if you want to Steve :

Just double up on the nuts on front carb fasteners and remove the studs , this will free the throttle actuator shaft..

 

[Healey Nut]

I just went out and had another tinker . Engine off ignition on fuel pump runs and builds pressure no ticks pump pressure up no leaks . Lift choke lever on front carb and fuel starts leaking out around the horizontal choke rod . It's not dripping from the plastic tubes which would be a bad jet seat .

 

[Patrick67BJ8]

I just went out and had another tinker . Engine off ignition on fuel pump runs and builds pressure no ticks pump pressure up no leaks . Lift choke lever on front carb and fuel starts leaking out around the horizontal choke rod . It's not dripping from the plastic tubes which would be a bad jet seat .

Bad diaphragm! Do one carb at a time if you've never done this job before because you don't want to mix up the parts. You will have to have a set of carb tools because you'll be centering the jet/diaphragm. Also buy carb to intake manifold gaskets to. Note which was the gaskets with the metal in them face! Use a digital camera and take pics of each step you do.

 

[Healey Nut]

So I guess this is what I need ?
Diaphram is top right in the pic ?

 

[Patrick67BJ8]

So I guess this is what I need ?
Diaphram is top right in the pic ?

I think the squarish carb gaskets with the foil om one side are not there. I don't see the "needle" that goes into the jet in the center of the diaphragm. Maybe the Jg & Healey use the same diaphram but I'm not sure. You can send a message to the ebay lister and ask.

 

[BJ8Healeys]

Bad diaphragm! Do one carb at a time if you've never done this job before because you don't want to mix up the parts. You will have to have a set of carb tools because you'll be centering the jet/diaphragm. Also buy carb to intake manifold gaskets to. Note which was the gaskets with the metal in them face! Use a digital camera and take pics of each step you do.

Good advice, but special carb tools are not required to center the jet on HD8s. If you need the procedures for changing the diaphragms and centering the jets, please contact me: sbyers@ec.rr.com

 

[Patrick67BJ8]

Good advice, but special carb tools are not required to center the jet on HD8s. If you need the procedures for changing the diaphragms and centering the jets, please contact me: sbyers@ec.rr.com

I always check the centering of the Jets when I rebuild my Carbs since I got them that far apart. I also like the SU tool kit to check proper Carb aoperation when throttled(both carb pistons must rise together).

 

[Keoke]

These are :

HS6 Carbs. HN

So I guess this is what I need ?
Diaphram is top right in the pic ?

Yep just make sure it is the right one for a Healey 3000 MKIII--The newest ones are also compatible with this lousy gas we have here in California too.

 

[Healey Nut]

Mine look nothing like that . Mine are HD8

 

[Keoke]

Mine look nothing like that . Mine are HD8

That is what we all been saying>---:highly_amused:

 

[steveg]

I think the squarish carb gaskets with the foil om one side are not there. I don't see the "needle" that goes into the jet in the center of the diaphragm. Maybe the Jg & Healey use the same diaphram but I'm not sure. You can send a message to the ebay lister and ask.

Moss PN 375-328 Rebuild kit does both carbs for $120 with the needles included. Plus you'd be sure of getting the right .0125" jet.
PN 378-330 is the jet assembly at $38 each. XKs Unlimited gets...

 

[Healey Nut]

I'm very dubious about some stuff from Moss . To much Won Ton Chang stuff .
I know it says genuine SU but .......
My carbs were fully rebuilt by apple hydraulics 5 yrs ago throttle shafts done etc the whole kit n kaboodle so I think I will just order two new diaphragms from XKs unlimited .

What is the lifespan of carb diaphragms ? 5yrs doesn't seem very long to me ?

 

[steveg]

I'm very dubious about some stuff from Moss . To much Won Ton Chang stuff .
I know it says genuine SU but .......
My carbs were fully rebuilt by apple hydraulics 5 yrs ago throttle shafts done etc the whole kit n kaboodle so I think I will just order two new diaphragms from XKs unlimited .

What is the lifespan of carb diaphragms ? 5yrs doesn't seem very long to me ?

FWIw - Moss lists the same PN for the XKE HD8 jet as for the Healey and describes it as .125", as they do for the Healey.

There was a problem with the diaphragms due to differing fuels with ethanol, Calif blend, etc. They've probably solved it by now.