14 replies to this topic

[charliefarlie37]

Morning....
How critical is a the float level in a hif38 carb?
Where should the fuel level sit in regard to the overflow, and how far away from 'book setting can you be before it gives fuelling issues?


I'm having trouble with my hif38. I've had it reconditioned and set the float according to videos on you tube( curve of float bowl just under level of carb base)... I'm getting fuel out of the overflow on tickover.
Obviously this means the float level is too high,but having set up the float according to 'book' settings I can only assume that the slight angle the carb sits on the inlet manifold is effecting the float/fuel level?
Has anybody else had this issue? Will experimenting and altering the float level until I get no overflow of fuel drastically risk the chance of fuelling issues and fuel starvarion?
Cheers

[cal844]

There is a proper procedure to adjust them.

http://sucarb.co.uk/...tter-reassembly

This will help

[charliefarlie37]

I've set it according to that, but getting slight weep out of the overflow, was wondering if anyone else had come across this,how much they had to adjust the level and if it caused any fuelling issues?

[nicklouse]

then either the float needle needs replacing or your fuel pressure is incorrect. Presuming the inlet is correct to give a suitable carb angle.

[ukcooper]

I set mine just about leave when I had a sprite1995.

 

Because it was a cross over year between carb and inj it had a return petrol line fitted and it was blocked and made the car run like poo so just disconnected it ran perfect after

[charliefarlie37]

Carb has been reconditioned by a specialist, new fuel pump too.
Had this issue ages ago but a friend altered the float level and it was then fine.
Just wondered if anyone else had this issue and if it was down to the angle of the inlet manifold. Can't see how a manifold with less of a angle would work as the carb would fowl on the bulkhead.
I could alter the float level but at what point would it cause fuelling issues.

[carbon]

Dirt/rust from the fuel tank can also cause sealing problems on the carb fuel inlet needle valve. This can result in carb flooding.

 

Do you have an in-line fuel filter fitted?

[charliefarlie37]

I'm over cautious, I've 2 inline filters, one near the electric pump under the rear subframe and one in the engine bay...
Carb didn't overflow before the recon and refitting but I know a mate set the float different to book setting, just wondering if anyone else has had this problem...don't think it's excessively angled when looking at other people's engine bays, but it's the only thing I can think is making it overflow.

[charliefarlie37]

I'm over cautious, I've 2 inline filters, one near the electric pump under the rear subframe and one in the engine bay...
Carb didn't overflow before the recon and refitting but I know a mate set the float different to book setting, just wondering if anyone else has had this problem...don't think it's excessively angled when looking at other people's engine bays, but it's the only thing I can think is making it overflow.

[charliefarlie37]

Are these connections correct?  20181111_180015.jpg   26.09K   2 downloads

[nicklouse]

almost but that is not a Mini SU.

 

B would not be there so block

A would not be there and is different but in a similar place and is for the vac advance.

[charliefarlie37]

My carb has all those connections, I've a vacuum take off the other side from the port labelled A...
I've seen this type of carb used on minis in pictures, it's actually the connection labelled B that I have fuel weeping out from, I was led to believe this was the float chamber overflow.

[nicklouse]

like i said it is NOT one found on Minis

the mini ones just have these four connections.

lower red fuel in upper red fuel overflow

blue connection the crank breather system or Block off.

green vac advance

 Capture.JPG   54.14K   4 downloads

[russo]

I have twin 1 1/2 HIF Carby's on my Mini. I have fitted new needle and seats, floats, jet tubes, needles and gaskets etc. I have set them up as per manufactures specifications. They sit at a 30 degree angle and I've been told by SU direct that these carbs will run up 40 degrees OK. The problem I have is that I can't seem to stop fuel spilling out the float overflow tubes. I have a facet pump fitted and have checked the fuel pump pressure which is well within the max. pressure allowable. Because of the 30 degree angle should I alter the float level to compensate? Has anybody had a similar problem when running HIF carbs at a 30 degree angle. I used to have the overflow tubes running into a bottle which I had to emty every 10 or so miles. The very strange thing is that one day for no reason it stopped doing it and hasn't done it since in the last couple of years and I have done nothing different.

Edited by russo, 11 November 2018 - 08:13 PM.

[GraemeC]

I run twin HIF4s on a Maniflow steel inlet manifold, Facet Silver Top pump and Filterking regulator (set at 4 psi IIRC).
I have no problem with fuel overflow.