MGExp

MG Midget Forum

float bowl overflow

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
yes i did start a new thread having narrowed down the issue, my bad. the other steps we have already checked out would have been helpful for all to see.

Jack mentioned the overflow port- its a tiny hole with a dust cover over it- it sits just below the hose that runs fuel to the rear carb. there is no copper tube out and overflow hose like other carbs.

as for rubber bushing, I look at the exploded view and assume we are talking about ref # 11 and 17
these guys look to me like they were made to swivel....I am wondering how much is normal.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

Attachments:
hs2 carb.jpg    56.5 KB
hs2 carb.jpg

dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
ok guys- heres the link to my previous post

https://www.mgexp.com/phorum/read.php?3,3740786

it seems the opinion is, its the float/valve alignment.
that makes sense of course...but still the little rascal wont cooperate.

changing back to the Viton valve I see how the idea of it binding when the float drops can occur.
I'll keep adjusting..

ice Avatar
ice Gold Member Larry Ice
Lawrenceville, GA, USA   USA
Doug, you are correct on the part numbers.

Jack, you have vibration mounts that are in good shape so not much movement where I would think Doug's are older and compressed allowing movement. I don't think Doug has enough movement to worry about. If you look closely at the first pic and the last pic you can see the small aluminum guide right at the end of the fuel line(near the hose clamp). The fuel line holds it in place as I recall. Depends on the model of the carb as to it having a actual brass overflow pipe on the float bowl cover.

Just went out and looked at my carbs. The frt carb has three lines attached to it. 1. fuel line in, 2. fuel out (to rear carb) and 3. overflow . There were originally a frt and back overflow tubing that I don't see listed anymore from VB or Moss. The purpose of the fuel line overflow tubing was to direct the overflow down and away from a heat source, didn't seem to me to be very effective though usually the overflow simply got the fuel away from the carbs at the expense of getting it nearer to the header! OBTW, my rear carb has two hoses, 1. the incoming fuel line and 2. the overflow line. On my carbs I installed (frt and rear) longer tubing at the float bowl port to direct fuel away from heat.

If you wanted to get the later version of float bowl covers I guess you would have to look for other sources or find them on a parts car. Maybe Hap or Gerard or fellows have some ideas where you can get the covers. Don't think the newer design will do anything for performance though.

If I get out to the shop with my camera I will take a couple of pics of my carbs.



Iceman

Atlanta GA

60 AH MK1
62 AH MKII
67 Midget
71 Midget

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
1974MGMidget Avatar
1974MGMidget Silver Member Jack Orkin
Grayson, GA, USA   USA
Doug, are your float bowls perpendicular, or close to perpendicular, or plumb, to the ground? Not sure if that would affect the float needle seat, but seems like various permutations of the A-series have the carbs at different angles due to various manifolds, etc. So, the little rubber mounts come in 3 or 4 different angles to keep the float chamber vertical, and not necessarily parallel to the carb body. Maybe one of our more knowledgeable members will chime in, or you could check with Joe Curto.

dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
Jack,
I would call the floats "close to perpendicular" with the carb...the carb is slanted backward a hair, the float bowl I would assume wants to be somewhat plumb up and down..

heres points of concern...I may just be nitpicking now...I know the float level adjustment has to be properly done first but<

the pic shows #1 the location of the overflow hole behind the little aluminum dust cover...
#2 shows the vacuum line which can interfere sort of hanging up the floats top screw from coming to plumb by holding in back a bit....to the left, tilted toward engine... this seems to be the worst leaking when i physically move it to that position..although, due to the orientation of the float hinge inside, this would have the float rising to engage the valve at a more acute angle and therefore shutting it off...
#3 shows where the fuel line leading to the rear carb contacts the heat shield at the hose bend and puts a good bit of pressure on the bowl forcing it to the right.

not sure if 2 and 3 are a concern...

but first things first- i have to get that float height correct...
but i must ask- on an HS2 carb, with conical float..is there a definitive float height measurement? I've seen everything from 1/8" ( Hanes manual) to 3/8" ( John Twist University Motors)


Attachments:
Inkedfloat 2_LI.jpg    45.4 KB
Inkedfloat 2_LI.jpg

dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
heres a pic from the side of the bowl in relation to the carb..both seem to be at same angle- the camera is straight and level.


Attachments:
HS2 carb to bowl angle.jpg    40.6 KB
HS2 carb to bowl angle.jpg

1974MGMidget Avatar
1974MGMidget Silver Member Jack Orkin
Grayson, GA, USA   USA
Doug, I just don't know if that would be an issue or not. If they are both like that, and it is an issue, I would assume they would both have fuel coming from the vent. I was hoping someone else would chime in with an opinion...

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
heres a little info i found concerning the float bowl angle compared to the carb

a 1275 Sprite with HS2, the float bowl should be 20 degrees different from the carb to get the bowl near level....and the grommet that mounts it is notched for that. apparently there are 20's and 30's.
also I've seen lots of videos of guys handling these carbs and never do i see that float bowl move or twist like mine does. they all appear pretty rigid.
so i'm going to re-grommet and adjust those floats and see what happens with the leaking

the specs about float bowl angle is on this link at the 10:42 mark.

refisk Rick Fisk
Frankenmuth, MI, USA   USA
The float bowl should be vertical. The angle your's are at could be the whole issue. Different cars have the carbs mounted at different angles and it appears you have the wrong adapters.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
ok, thanks guys for once again helping solve a problem by taking me down a path I alone would likely have never considered without your input.

so heres the story in pictures-
my overflow problem is partially float adjustment, but also the angle the float bowl itself was mounted. PO apparently had switched the front and rear keyed grommets that hold the float bowls to the carb.
picture shows how it was, then after switch the grommet from the rear to the front you can see the difference- the "wrong position" is marked with red pen pointed out by the screrwdriver.

the next pic shows how the bowl will sit next to the carb- it is much more level when properly mounted, with the over flow sitting a bit uphill ( 20 degrees) instead of downhill when the grommets were reversed.
I have new grommets on the way and will verify the leak is solved when all is installed...
thanks again for bearing with me and guiding me to take a closer look!


Attachments:
float grommet front.jpg    34.2 KB
float grommet front.jpg

float grommet from rear moved to front.jpg    28.2 KB
Sign In or Register to view this photo
new float angle.jpg    40.5 KB
Sign In or Register to view this photo
refisk Rick Fisk
Frankenmuth, MI, USA   USA
That's still too much of an angle, but now the other way. The top of the float bowl should be parallel with the floor, just like the radiator cap in you last photo. The bowl itself should be perpendicular to the floor. smileys with beer

maraud Avatar
maraud Gold Member Sean K
Longwood, FL, USA   USA
Interestingly I'm still struggling with the same problem on my Midget 1500 that I converted to SU HS4's. I have that same vent/dust cover and mine happens when at or coming off up 50+ throttle or more. I've dialed the fuel pressure down to 1.5PSI which has greatly reduced the issue but it still happens from time to time. Very frustrating. I'm not running an SU pump, but rather a centrifugal 1-4PSI pump that I've regulated to just under two PSI. I've tried adjusting the the float height, and my float bowls are as close to vertical as one can get. It's just nusto as the back one (firewall, first one in line from the fuel filter) doesn't do it. I've even swapped the float/pins and no change. Tried grouse as well... Consider me stumped at the moment.

Poundingsand Avatar
Poundingsand Silver Member Peer Ebbighausen
Los Angeles, CA, USA   USA
Sean, I mentioned earlier in the thread to Doug to drive the car to replicate the condition, then feel the float bowls. My car did the same thing recently (spit fuel only after a freeway run) and it turned out I was too lean at wide open throttle. My float bowls were extremely hot and the fuel was boiling over...it never vapor locked - just ran extremely lean. A richer mixture cured the problem.

dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
i have to agree with Rick that now its just angled the other way....seems logical to me that the bowl should be verticle with the float and all...perhaps i will just craft my own grommet with a razor knife and move what i cut out to fill the void thats already there. you see in the picture below there is a key on the carb the bowl grommet mates up to at some predetermined British engineered angle to promote continuous tinkering and frustration with the whole works.


Attachments:
1528754642307-632779025.jpg    31 KB
1528754642307-632779025.jpg

dbnoaol Avatar
dbnoaol doug bowers
milford, OH, USA   USA
more float bowl observations lead to more questions....
notice the pics.
the bowls are different inside. they are the same model AUG 1310...there is further designation number below that...front and rear?
perhaps the grommets werent swaped, the entire bowls were?

also, notice the openings on the jets...they are different sizes, ( same part #) ordered from Moss as pair and installed myownself.
is this a concern...is there a front and rear difference required to the jets or the bowls?


Attachments:
15287622557251346730561.jpg    29.5 KB
15287622557251346730561.jpg

15287623960201092078202.jpg    33.8 KB
Sign In or Register to view this photo
. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster