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From: Tony Jones on 11 Jul 2010 17:43 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
From: Harry Bloomfield on 11 Jul 2010 18:39 Tony Jones expressed precisely : > 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? 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. > 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? 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. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk
From: newshound on 11 Jul 2010 18:43 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.
From: Tony Jones on 11 Jul 2010 19:21 newshound <newshound(a)fairadsl.co.uk> wrote: > > 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. You mean something like this (random eBay selection): http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=360254115297 before 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
From: Rob Graham on 12 Jul 2010 04:51
On 11/07/2010 22:43, Tony Jones wrote: > 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 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 |