16 replies to this topic

[BaronVonchesto]

Was having problems with my engine not running properly and not responding well to the throttle, so I decided I'd just go for a full carb rebuild.

Got the waxstat rebuild kit from minispares (including new float) and followed the Hanes instructions almost to a T. Reinstalled the carb in my car but couldn't get engine to start. I noticed that the carb was leaking fuel. Closer inspection showed that fuel was leaking out of the inlet (see pic)

 

Now im certain that the fuel hose is of the correct diameter because its quite snug, and the hose clamp has been tightened as much as it can be, yet fuel still seeps out from the host if the engine is cranked a bit which tells me that the fuel pressure is quite high and isn't getting into the carb as it should.

 

When I removed the float bowl cover, the float appeared wet with fuel, but the fuel level in the float bowl seemed pretty low.

 

I've tried it with and without the provided washer in the kit for the float needle seat, which seems to have not made any difference. Also there is no fuel coming out of the overflow pipe.

 

The one thing I have not properly checked for is a blockage in the inlet pipe. However if I blow into the inlet pipe (without my lips touching of course), there is a slight difference in sound with the float all the way down, and with the float raised slightly.

Any advice would be appreciated.

PS: My engine still doesn't start, but I'll seek help for that problem after I stop this infernal leak :)

 

Attached Files

•  carb1.jpg   66.35K   5 downloads
•  carb2.jpg   35.22K   2 downloads

[BaronVonchesto]

My carb is a HS4 waxstat model by the way, and as per the Hanes manual I set the jet to be flush and then made 3 full rotations down.

Here's a list of what was changed:

All gaskets
Jet
Float & pin

float needle

Float seat

Throttle Spindle

Butterfly valve (the throttle circle thing)

[Ethel]

Fuel shouldn't leak from there, even a properly working carb will stop fuel entering when the float bowl's full. See if the hose is split. You might also be better off with a proper hoseclip, small jubilees often don't clamp evenly because the worm screw is a large part of the circumference

 

 or 

[cal844]

Change the clip for the type in the first picture in Ethel's post. Also check the hose isn't split or degraded.
To test the float valve you ideally need to seal your lips around the inlet, blow through then lift the float(close the valve)

[Spider]

The obvious and first places to check as as Ethel has suggested, however, if could be the tube leaking where it's cast in to the lid.

 

If this is what it is, and if you can get the tube out, and the lid's not cracked, you can clean them up and loctite them back together.

[BaronVonchesto]

hose is new so I doubt its split, but will check carefully just in case.

Also have the original hoseclip so I'll try to fit that one on, though the reason i switched to the screw type was that I was having trouble getting the original clip back on.

Will also retest the inlet.

 

By the way what sort of adhesive is loctite? Super glue? an epoxy of some sort? The sort of stuff we get over here often has different brand names

[carbon]

Baron,

 

Are you're using 8mm ID fuel hose? If yes then this may be the root cause of the problem, as the diameter of the brass pipe on the HS4 float chamber is only 6.4mm,

 

These connections seal best if the fuel pipe is a snug fit with the hose clamp loose.

 

Before trying to start the engine you need to either reconnect the breather pipe to the carb body (you may have removed it to take the photos?) or just cap it off. If you're having trouble starting the engine I would recommend capping it to start with, and then reconnect breather later.

[BaronVonchesto]

The fuel pipe fits fairly snugly, though not absolutely tight. I got the fuel line off my mechanic, where we tried different sizes until we found one that seemed to fit well.

Will get a micrometer and measure it to be sure.

[BaronVonchesto]

also yes I only removed the breather hose to take the picture, but as you say I shall cap it off until i get the engine running.

[Spider]

 

By the way what sort of adhesive is loctite? Super glue? an epoxy of some sort? The sort of stuff we get over here often has different brand names

 

You should be able to obtain Loctite in your part of the world. Loctite 243 will do the job and you'd be able to use it for other things too.

 

https://www.lelong.c...ctite-malaysia/

[MiniMoe2008]

Just want to make sure is it the hose leaking or the fitting from the carb? I've had to use loctite medium blue grade. Link below. I've also used in a pinch plumbers tape. Not the greatest but better than leaking everywhere.

 

http://www.na.henkel...d=8797710090241

[BaronVonchesto]

Well I went to Ace Hardware, but they didn't have any loctite threadlocker compounds, instead I got a different brand, Vtech blue threadlocker. Hope that works similarly well to loctite.

 

applied it all over the fuel inlet and also applied it on the threads of the needle seat before reinstalling it. Then i fitted the fuel hose (which is the right size by the way) and the original clamp as suggested by Ethel.

 

closing the needle seat valve and blowing into the fuel inlet as hard as I could, i saw tiny bubbles coming out between the fuel hose and the carb body.

 

Will let it cure for 24 hours, hopefully that will stop the leak.

[carbon]

The brass tube inlet pipe is a press fit into the float chamber cover, and should make a perfect seal.

 

You shouldn't see any bubbles coming out between the fuel hose and the carb body

 

They are normally solid, might just be that yours is loose? I would check carefully, and if it is loose you will need to carefully take out, clean up, and then replace with threadlock or sealant. Or better still find a replacement float chamber cover.

[BaronVonchesto]

The brass tube inlet pipe is a press fit into the float chamber cover, and should make a perfect seal.

 

You shouldn't see any bubbles coming out between the fuel hose and the carb body

 

They are normally solid, might just be that yours is loose? I would check carefully, and if it is loose you will need to carefully take out, clean up, and then replace with threadlock or sealant. Or better still find a replacement float chamber cover.

Yea this is the last resort. The brass tube appears snug. There might be a tiny hole from somewhere. If the threadlocker can't seal the leak, then I guess theres no choice but to replace the float bowl cover

[Spider]

The Tube is either cast in or pressed. I've had a couple leak and if that's what was found leaking, that's what I was suggesting removing, and refitting with the loctite (even though it's listed as a thread locking compound, it will also seal press fit fittings like these).

 

I can't see it being the needle and seat or it's thread.