16 replies to this topic

[sam138]

Just need some help please I've rebuilt a hif44 carb which was from a non mini but it's overflowing with a large flow of fuel and black smoke out of the exhaust . I believe I've blocked off the correct non use outlets but correct me if I'm wrong . i have attached some images of the carb and float , could this be to do with the float clearance ? How should it be ? The carb was rebuilt with a full rebuilt kit .

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[Compdoc]

To check the float level, turn the carb upside down, i.e  with the float at the top, with the float resting on the needle valve under its own weight. Put a straight edge across the rim of the float chamber so that it passes over the centre curved part of the float. The distance from the straight edge to the float should be 1.0mm +/- 0.5mm. (Some manuals say 2.0mm but this is for the later floats that do not have the metal tang that rests on the needle valve).

Can't help you with the blocked off ports though.

[Ethel]

Could do with seeing the other side, the hose clip in the bottom photo looks to be on a fuel inlet, for all it's on the opposite side to usual. The capped port on top, 2nd & 3rd photo is the part throttle weakening device, you can cap it, but the other end of the hose should go to thus:

 

The other 2 pipes are fuel inlet nearest the camera and fuel overflow furthest. Don't be confused by the throttle linkage, it's on the other side to yours. Note also the communication ports on the air filter mounting face and check that none are covered by your gasket or filter casing.

 

Lots of other possibilities for the leak, let us know how the above checks out, but does it leak externally and what fuel pump are you using?

[sam138]

Thanks for the reply , if it's not correct do you just bend the metal tab to float valve to adjust height ?
Also attached a further picture of needle float valve which I'm not sure if it's correct way around ? The carb was from a twin set up and have no external leaks just straight out the overflow pipe . The fuel pump is a brand new mechanical one from minispares as below which was recommended by them for my 1275 Cooper engine .
http://www.minispare...18.aspx|Back to

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[sam138]

I've attached a further photo and coloured dotted what I've connect up .

White dott - breather
Red Dott - over flow pipe
Their is one more pipe below on that side ( not in photo ) but I have connected this to fuel inlet same as other side in picture which is capped off .

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[sam138]

With the float needle valve should the arrow shape be up side or down facing the metal on the float valve ?

[Spider]

Have you check the fuel pump pressure?

 

What fuel pump are you using?

[sam138]

Thanks for the reply this pump was recommended to me by Minispares .

http://www.minispare...18.aspx|Back to

[Spider]

Thanks for the reply this pump was recommended to me by Minispares .

http://www.minispare...18.aspx|Back to

 

That should be OK, however, I have had two now that have had higher than rated pressure. Best check with a gauge, you might be looking in the wrong place.

[Compdoc]

With the float needle valve should the arrow shape be up side or down facing the metal on the float valve ?

The arrow head shaped end fits into the brass tube leaving the tiny sprung end touching the underside of the floats tang. You bend this tang to adjust the float level. If you have the needle valve upside down it would definitely flood. The float in your picture is in the correct position.

[nicklouse]

Just need some help please I've rebuilt a hif44 carb which was from a non mini but it's overflowing with a large flow of fuel and black smoke out of the exhaust .

just wanting clarity on this. you are seeing fuel out of the overflow pipe.

 

the modern needle valves are said to be good for 10psi so if it is closing it should hold that pump with ease.

 

so that leaves float height. the how to set it is in the kit IIRC if not it is on the SU website tec section.

[Ethel]

Ok, if there's just one pipe out of view in the last picture, I think we've cracked it.

 

Like I said the red dot pipe is part of the weakening device (saves fuel when cruising etc). The pipe directly under it is the fuel overflow/ float chamber breather. There must be only one fuel inlet, which is the one capped off on the other side. Saves me asking another question, if that snazzy blanking cap is silicone it's not really suitable for fuel unless it has a butyl lining.

[sam138]

I've attached some further images of the side of the carb and turned the valve float needle around the correct way .  IMG_3324.JPG   44.86K   9 downloads

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[sam138]

So should from the side pic of the car do you think the top right out of the three is for crank breather and top back to join into the weakening device which is capped off and the bottom of the three being the carb overflow ? And the fuel intoet on the other side ?

[panky]

Ok, if there's just one pipe out of view in the last picture, I think we've cracked it.

 

Like I said the red dot pipe is part of the weakening device (saves fuel when cruising etc). The pipe directly under it is the fuel overflow/ float chamber breather. There must be only one fuel inlet, which is the one capped off on the other side. Saves me asking another question, if that snazzy blanking cap is silicone it's not really suitable for fuel unless it has a butyl lining.

 I agree. If it's one of pair of twins then the fuel inlet will be on the same side as the linkages and the second carb a mirror image with a 'T' piece feeding the inlets.