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HIF44 carby float valve issue
https://ausmini.com/forums/viewtopic.php?f=2&t=93396		 Page 1 of 1
Author:  Morbo28 [ Tue Aug 09, 2016 1:55 pm ]
Post subject:  HIF44 carby float valve issue
Hi everyone,

I've got some flooding issues with my HIF44 and I think it is the float valve. A bit of history
* It's a brand new carby (though I see what looks like varnish/solidified old fuel at the bottom of the float bowl; I had let it sit with fuel in the bowl for a while so that was probably down to me)
* When the engine was first built I was gravity-feeding the carby with fuel to run it on the bench and it worked fine
* I connected a 4psi fuel pump and excess fuel was flooding the carby and dropping out
* I then fitted a fuel pressure regulator and it's set just below 2psi but the problem persists
* So I tried gravity feeding the carby and it still floods now
* The rubber needle valve point looks like it's in good condition
* When I hold the needle valve closed with light pressure with my finger it successfully closes the valve and no fuel gets in
* I have tried adjusting/bending the metal tab that is joined to the float that pushes on the valve to close it. It either seems to permanently keep the valve closed (when bent too far) or when backed off just a little it doesn't close the valve and the fuel spills out when gravity fed


In some way, the fuel still isn't closing the float valve. Any ideas????

Here's a token pic of the carby as it was setup when I was testing it with gravity fed fuel.
Image

And just to check in, it shouldn't make a difference that I'm testing it with no needle installed should it?


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Author:  simon k [ Tue Aug 09, 2016 3:42 pm ]
Post subject:  Re: HIF44 carby float valve issue
you should be able to hold the carb upside down and blow (with your mouth, not an air compressor) the fuel inlet and have it seal - if it doesn't then your new needle and seat doesn't work, or you'll find where the air is getting into the float bowl

and no, won't make a difference with no needle/dashpot etc.
Author:  gtogreen1969 [ Tue Aug 09, 2016 4:15 pm ]
Post subject:  Re: HIF44 carby float valve issue
The needle and seat may have some gum on it. Yes thats my technical term for the hardened residue left over after some fuels evaporate.
Author:  Morbo28 [ Tue Aug 09, 2016 4:24 pm ]
Post subject:  Re: HIF44 carby float valve issue
Okay thanks guys. Looks like the seat unscrews. I'll pull it out and give it a clean and if it's still not working I'll replace it.

If I do need to replace it, I see there are genuine items but also this 'uprated' item. Any idea if I should get the fancy pants one or just standard?


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Author:  Morbo28 [ Tue Aug 09, 2016 4:28 pm ]
Post subject:  Re: HIF44 carby float valve issue
Link would help http://minisport.com.au/mini-competitio ... -ball-type

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Author:  gtogreen1969 [ Tue Aug 09, 2016 4:35 pm ]
Post subject:  Re: HIF44 carby float valve issue
Yes the grose jet style is a good upgrade. I bought this style. http://www.minimania.com/part/AUD9096GR ... e-And-Seat
Author:  timmy201 [ Tue Aug 09, 2016 4:41 pm ]
Post subject:  Re: HIF44 carby float valve issue
Morbo28 wrote:
Link would help http://minisport.com.au/mini-competitio ... -ball-type

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"Fits HS2, HS4, HS6"

http://www.minispares.com/product/Classic/CA90.aspx

I can't see any others to suit HIF other than this one
http://www.minispares.com/product/Class ... 1099A.aspx
Author:  Morbo28 [ Tue Aug 09, 2016 7:25 pm ]
Post subject:  Re: HIF44 carby float valve issue
Ah you're right, I'll grab the standard ones then. I see there are standard/non-turbo ones or turbo ones and it appears they aren't interchangeable. I'm going to assume I have the non-turbo.

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Author:  minimanic [ Tue Aug 09, 2016 9:07 pm ]
Post subject:  Re: HIF44 carby float valve issue
I can't quite see on your photo, but the tube that is blanked with a plug on the carb may possibly be the bowl vent.
These carbs do all sorts of strange things with the fuel level in the bowl if the vent is pluged from flooding to not letting any fuel in at all.
I have seen needle and seats damaged from too high fuel pressure, but if this is the case the needle will have a noticable ring where it touches the seat.

Ben.
Author:  simon k [ Tue Aug 09, 2016 9:41 pm ]
Post subject:  Re: HIF44 carby float valve issue
minimanic wrote:
I can't quite see on your photo, but the tube that is blanked with a plug on the carb may possibly be the bowl vent.


good pickup Ben - I that is the vent...
Author:  Morbo28 [ Wed Aug 10, 2016 7:27 am ]
Post subject:  Re: HIF44 carby float valve issue
Yep, that's the vent :) From what I understand the vent has two exits? An external one (blanked with a plug) and the same passage also leads to inside the air filter I was lead to believe? I will have a closer look.

I did actually try removing the plug when I was trouble shooting with the pump connected and it shot a nice little spurt of fuel into the engine bay out of the vent pipe :)

For arguments sake, if I was to unblock that vent, would I leave it bare or route a hose somewhere?

I'm leaning towards the theory that the valve is gummed up, given the residue on the bottom of the float bowl and given that the fuel pump is only 4psi at the pump and theoretically I should have been right to run it without a reg.

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Author:  simon k [ Wed Aug 10, 2016 7:38 pm ]
Post subject:  Re: HIF44 carby float valve issue
Morbo28 wrote:
For arguments sake, if I was to unblock that vent, would I leave it bare or route a hose somewhere?


definitely route a hose, mine goes into the air filter

edit: and mine doesn't have any other vent - that's the only one, yours may be different but I'd be testing it by putting the bowl back on, blocking up the jet and blowing into it
Author:  Morbo28 [ Wed Aug 10, 2016 11:02 pm ]
Post subject:  Re: HIF44 carby float valve issue
Okay - this afternoon Simon I did exactly that...it is the only vent. With it blocked, the air must vent out through the jet. Because the jet draws from the bottom of the float bowl, fuel was getting pushed up the jet.

So minimanic/Ben you were right on the nose, good pickup.

Now there must have been some float valve sealing issue for at least a short period, because I uncapped the vent at one of the trouble shooting sessions and with the pump on, fuel came out of the vent?

All sorted, anyway! Though I will replace the rubber tip of the needle as I damaged it when cleaning it up. One is on its way from MKO should arrive tomorrow.

Thanks heaps for all of your help, much appreciated :)
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