11 replies to this topic

[hughzy69]

Hi guys I took my dash pot off today along with plunger etc as the oil I filled it with a week ago has vanished lol, refilled with some 3in1 oil and I noticed the oil is actually running out of one of the holes in the bottom of the plunger by the side of the needle?

So the question is Why is it doing this and how do I stop it?

Cheers

[Globule]

Are you sure you are just filling the central bore of the carb where the brass plunger sits, as opposed to the area around this? If you filled the whole carb, then yes it would leak out of the holes, as the oil should not be there and so the engine would burn it off

[hughzy69]

Yes mate only filling the centre piece which the plunger sits in.

[Globule]

Then the centre steel tube must be broken away from the aluminum piece, allowing the oil to weep out, and through the holes! But, this is very unlikely to have happened.

[austinmini1963]

out of interest, is it loosing all the oil out of the dashpot?

[hughzy69]

Yeah all of it

[Globule]

I decided to take a picture:

Are you sure you are filling the dark centre tube, or the whole thing?



I just cannot see how the centre tube would be leaking it into the bottom of the aluminium housing, it's thick steel in an area that sees limited force

[dklawson]

Please see the pictures in the links below.

See the picture and note the level of oil and where the oil is.
http://www.sucarb.co...tail.aspx?id=93

Read section #4, see figure 6b
http://www.sucarb.co...tail.aspx?id=73

If the innermost steel tube is unbroken there is no path for the oil to leak out of the dashpot/damper. A very common mistake is to misinterpret what "full" means. If you fill the entire center of the carb up with oil (right up to the threads where the dashpot screws in) then the oil will flow down between the innermost tube and the boss that guides it. The oil then finds its way down into the inside of the piston... and drips out of the two holes at the back of the piston.

Refer to the picture in the first link and stop filling the innermost tube when the oil is about 1/4" below the top of the inner tube.

[hughzy69]

I decided to take a picture:

Are you sure you are filling the dark centre tube, or the whole thing?



I just cannot see how the centre tube would be leaking it into the bottom of the aluminium housing, it's thick steel in an area that sees limited force

Yes I'm only filling the centre bit mate! And mines a hiff44

Edited by hughzy69, 15 August 2012 - 10:57 AM.

[hughzy69]

Please see the pictures in the links below.

See the picture and note the level of oil and where the oil is.
http://www.sucarb.co...tail.aspx?id=93

Read section #4, see figure 6b
http://www.sucarb.co...tail.aspx?id=73

If the innermost steel tube is unbroken there is no path for the oil to leak out of the dashpot/damper. A very common mistake is to misinterpret what "full" means. If you fill the entire center of the carb up with oil (right up to the threads where the dashpot screws in) then the oil will flow down between the innermost tube and the boss that guides it. The oil then finds its way down into the inside of the piston... and drips out of the two holes at the back of the piston.

Refer to the picture in the first link and stop filling the innermost tube when the oil is about 1/4" below the top of the inner tube.

Yes this is what im doing and the oil is just seeping out one of the holes when it tilts forward slightly to locate the needle in the hole

[hughzy69]

The 2 holes and only one has oil leaking from it, it drips out when the plunger is down

Edited by hughzy69, 15 August 2012 - 11:09 AM.

[dklawson]

Regardless of HS or HIF carb there should not be a leak path from that center tube.

Your sanity check is to take a compressed air hose and supply air to the open end (left end as shown in your picture above) of the center tube. If you spray the piston assembly with soapy water (or dunk it in soapy water), bubbles from the compressed air will reveal where any cracks or problems are.

If the compressed air and soapy water reveal a leak path, replace the piston assembly AND the vacuum dome that it works in. The piston and dome are machined as a matched set. While you can sometimes mix components, you shouldn't.