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DIY gasket and fuel tank clean

In a previous thread I asked about the carb on my 1987 Mazda 626 1.6 LX and its idle problems. One of the suggestions was to have a look at some of the carb needles, which involves taking the carb apart. I've already taken off and replaced the carb a few times, so that bit's easy.

But the original carb gasket had to be chipped off in lumps. I managed to source some replacements for that, but Mazda UK have no source for the gaskets that go between sections of the carb, and if they exist in Japan they'll be months. The part number brings up exactly two hits on Google, both in Ukraine (and they don't look like they will actually sell me anything). I'm guessing finding this kind of thing from 'we import Japanese parts' suppliers is unlikely? There's nothing even remotely close on eBay.

So, if I take this apart, I'm going to need some kind of gasket. My options seem to be:

Instant gasket gloop - I get the impression this is a bad idea for a carb seal?

An old cereal box. I've seen that suggested, but really? Maybe that's just for (eg) a coolant gasket?

Get some gasket material and make my own. Is there any particular type of I should go for, and any recommendations for how to make a copy? I was wondering about smearing the old gasket with white paint/paste, and taking an imprint onto the new then cutting it out. Or maybe grease it and transfer the grease to card to use as a template. Are there any useful tricks to this?

The new carb/engine gasket is quite thick - maybe 0.75mm - so I doubt gasket 'paper' would do. I can probably try to micrometer that, but the old gasket that I actually want to replace is probably deformed into a lump so not very easy to measure. How fussy is it likely to be on thicknesses?

Any other tips on the best way to replicate this gasket?

On a related topic, I suspect the reason for trouble is muck in the fuel tank. As the fuel gets lower, I get random power loss more frequently. When I added about 10l of fresh fuel (current tank is 4 months old and has maybe 10-20l in it) it started and drove fine for about 20 miles. After about 20 mins parked, it then completely refused to restart... until I turned it over about 30 times and then it eventually fired. Since then it's been almost fine. So I wondered if the fresh fuel has disturbed the muck (more than the usual swishing around on corners).

So should I try to pump out the tank, or should I just let it run until it cuts out? I'm going to have to change the fuel filter and clean the carb anyway. What should I do with the pumped petrol? And then is there any way to remove the muck in the tank without dismantling it?

Thanks Tony

Reply to
Tony Jones
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Tony Jones expressed precisely :

Use either made for the job gasket paper, or brown paper as used for parcels. Use a hot soldering iron to burn a hole where one bolt hole goes, put a bolt in place, then burn the rest of the bolt holes. Then work on the larger holes and outer edges. The paper will not get hot enough to burn where it is touching metal.

I used to make some fairly delicate and intricate gaskets by this method.

Carb to manifold, not critical at all, providing it is sufficiently thick - cornflake packet will be fine. Use the hot iron method maybe combined with a small cross pein hammer to 'nick cut' the gasket material around its larger cuts.

Reply to
Harry Bloomfield

Seconded (all the gasket stuff).

As for the rubbish in the tank, why not just add a simple in-line fuel filter just before the carb. Under a fiver from eBay, some have clear casings so you should be able to see what's collecting.

Reply to
newshound

Will that work in a part that has fuel kicking about? These isn't just connector gaskets, they're are between the three sections of the carb, and have things like idle needles sealed by them - I think, I haven't taken it apart yet. Cutting the holes isn't such a problem - can wield a drill and a Stanley knife if I can mark out where to cut - but I wondered about the stability of the gasket material when heat and fuel are around.

I found another Ukranian website with a parts blowup:

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that suggests that the original gaskets are asbestos - I'm wanting13-XA6 and maybe the unmarked one below the label 23-440. Tony

Reply to
Tony Jones

You mean something like this (random eBay selection):

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the usual fuel filter? The previous filter (only on a few months) was a bit odd... when I changed it clean fuel came out the outlet OK, but the stuff that came out of the inlet looked like milk, and the plastic casing could be deformed easily. Not sure if that was a duff filter or there's some serious clag in the tank, but nothing much changed when I replaced it.

Tony

Reply to
Tony Jones

Sounds like water's got in somewhere and emulsified making it look milky. I'd have a good look at the petrol cap and filler area. Also check that the cap has a breather in it. It's possible that the tank, if it can't breathe, is working like a vacuum and not allowing enough fuel to flow through the pipes.

Reply to
Paul - xxx

The age-old method of making a gasket was to get suitable paper/material, hold it onto one of the parts to be joined, and gently tap round the holes in that part with something such as a bolt head, or some small blunt weapon, so as to cut the paper neatly at the right places. Always worked for me. And, yes, I bet a cereal packet would work just fine. You could put a smear of Hermetite on it if you wanted.

Rob Graham

Reply to
Rob Graham

Regards

Reply to
TMC

Have you tried a carb specialist like

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Not used them for years, but they were good then.

Reply to
Chris Bartram

Harry Bloomfield wrote in news: snipped-for-privacy@NOSPAM.tiscali.co.uk:

I rebuilt an entire GPz 305 engine using this process. A smear of red gasket seal on the cardboard helped too.

Reply to
Tunku

Should work fine- the main thing is to ensure there are no creases or burrs in the paper or card and that it properly clears the holes to ensure even pressure on the gasket.

I cannot think why they would be asbestos, there is no need for heat resistance around a carb. Asbestos would be illegal anyway these days.

Reply to
Harry Bloomfield
[...]

Many gasket materials *contain* asbestos for reasons other than thermal insulation.

What about in 1986?

Chris

Reply to
Chris Whelan

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