Alan Gordon 5 Posted November 6, 2019 Share Posted November 6, 2019 Hi Guys, I have aquired a Seagull Extra 300 with a Super Tigre 91 up front, No problems apart from the tank as supplied is a tight fit in the formers, the trouble is vibration in tank which in turn is causing bubbles in the fuel delivery to engine which in turn is causing eratic running, Any ideas on how to insulate tank to minimise this adgitation ? Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 6, 2019 Share Posted November 6, 2019 It is more likely an air pressure leak in the tank or one of the pipes Alan Also, an ST91 is usually quite smooth running, so double check the prop balance Quote Link to comment Share on other sites More sharing options...
cymaz Posted November 6, 2019 Share Posted November 6, 2019 If it’s tight in the formers , as you say, there are solutions a smaller tank cut away the formers Different design of tank. I always use Dubro turn the tank through 90*...you might get some useful space Get one of these and give it a try. Edited By cymaz on 06/11/2019 17:21:28 Quote Link to comment Share on other sites More sharing options...
Alan Gordon 5 Posted November 6, 2019 Author Share Posted November 6, 2019 I thought about cutting away the formers as this seemed the way to go with sponge surrounding the tank but being ARTF was concerned with weaking the structure. Will check prop balance though ! Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted November 6, 2019 Share Posted November 6, 2019 i've never tried it but I've seen recommendations to add a couple of drops of a product called "Armor All" (sorry about the spelling!) to a tankfull of fuel to eliminate vibration induced frothing. Perhaps someone who's tried it might comment? Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted November 6, 2019 Share Posted November 6, 2019 Posted by Martin Harris on 06/11/2019 18:38:10: i've never tried it but I've seen recommendations to add a couple of drops of a product called "Armor All" (sorry about the spelling!) to a tankfull of fuel to eliminate vibration induced frothing. Perhaps someone who's tried it might comment? Yes its a car interior dessing contains silicon . A squit of silcon based furniture polish does the same. It helps treat the result of vibration but its far better to treat the cause of the vibration. A fuel tank should be a good fit to stop it moving but some foam insulation is ideal . A smaller tank and some foam would help after you have balanced the prop and spinner. Quote Link to comment Share on other sites More sharing options...
Alan Gordon 5 Posted November 7, 2019 Author Share Posted November 7, 2019 Interesting regarding the polish, guys, I realise that enclosing the tank in foam would help but this being an ARTF the tank is good fit and I would have to cut away the former holding the tank to fit foam then I would be concerend with regards to loosing structural strenght. I take on board also the need to balance thr prop / spinner. Quote Link to comment Share on other sites More sharing options...
jrman Posted November 7, 2019 Share Posted November 7, 2019 +1 for silicon polish. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted November 7, 2019 Share Posted November 7, 2019 Personally, I wouldn't be too concerned about cutting the former - you can always reinforce it with some ply. Even if it is one of those laser cut "lots of holes" type formers, it could be doubled up to retain strength. What about a different shape tank? A longer thinner one? Quote Link to comment Share on other sites More sharing options...
J D 8 Posted November 7, 2019 Share Posted November 7, 2019 I recon just packing some foam around the tank as it is may fix it. After vibrations arrive through the wood work the tank sides themselves vibrate foaming the fuel. [ seagull tanks are nothing special ] Quote Link to comment Share on other sites More sharing options...
Alan Gordon 5 Posted November 7, 2019 Author Share Posted November 7, 2019 The present tank is 56.5 ml square, with an over all lenght of 120 ml I think I will try as Nigel suggestes getting a smaller tank but longer, will scout around the web !! Quote Link to comment Share on other sites More sharing options...
Robert Welford Posted November 7, 2019 Share Posted November 7, 2019 I've experienced issues with YS engines due to bubbles in the fuel supply. The solution is to use a felt covered clunk. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Alan Gordon 5 Posted November 8, 2019 Author Share Posted November 8, 2019 i would like to try this Robert, are they generaly available ? Quote Link to comment Share on other sites More sharing options...
Robert Welford Posted November 8, 2019 Share Posted November 8, 2019 Most felt clunks are used with petrol engines and turbines. The YS variant was smaller - unfortunately YS bits are now difficult to source within the UK. Alan, you'll have to see what will fit through the opening of your fuel tank. Sintered clunks will also eliminate the effects of bubbles. Search online and you should find what you are looking for. Quote Link to comment Share on other sites More sharing options...
Robin Colbourne Posted November 8, 2019 Share Posted November 8, 2019 Nexus do a felt clunk: Felt Clunk Quote Link to comment Share on other sites More sharing options...
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