Advice please... I need to stick a plastic fuel tap into the hole in the bottom of a plastic 2-stroke fuel tank (the tank looks like polypropelene) on an outboard motor. The fuel tap was originally a screw-in job but a previous owner stripped the threads. I used Araldite last time, but it didn't hold very well.
What adhesive should I try next? Superglue? I also have some Golden Hermatite. Perhaps that would work...
Unfortunately, that could take some time, since parts for this obsolete motor are hard to find. I'm just looking for a quick fix that's quick, cheap and reasonably secure.
You might be able to find a generic tank and tap a new hole into it (or with a correctly formed outlet already there). Is the tank some weird and wonderful shape, or would any old unit do?
You might be able to reinstate the thread using one of those whatnots... a metal spiral, forget the name. Or maybe make a ring that screws in, and the tap screws into that. Etc.
One thing you dont want is fuel pouring out, so I'd make it tough and secure.
The tank is a rather specific shape. It has to fit inside the outboard motor's upper alloy casing, and the cap has to coincide with a hole in the alloy casing.
But thank you for the suggestion.
Realistically, I'm just looking for the best way to use the current tank. Surely some kind of goo or adhesive will form a leakproof joint between the stripped petcock and the stripped hole in the tank...
Thanks; that might be the ideal solution, but it's more tricky and time-consuming than I want to get involved with.
Yes, within reason. I did use Araldite previously. It got me out of trouble, but, of course, there was no real adhesion there, so it was only hanging in there on a wing and a prayer.
I figure there must be something more suitable than Araldite...
I would try a large diameter, short brass nut, washers and bolt into a tight fitting hole with a "suitable-for-fuel rubber" washer each side - then drill and tap the brass bolt and screw in the (or a new) petrol tap. This assumes you can get a nut into the right position and it will self hold whilst tightening up ( use loctite ).
If not, and this assumes the plastic is thick enough, drill and tap a larger hole and either fit a petrol tap in direct, or a bolt which you can then drill and tap perhaps with a washer on the outside to strain relieve a bit.
Or as the others suggest - get a new or s/hand one but then thats not D-I-Y...
Also depends on "what if it leaks" - a lawn mower/ outboard motor I wouldn't worry so much, but if it leaks somewhere where vapours could collect, go the new route.
Unfortunately, the thread is stripped off the plastic petrol tap too. But tapping new threads is more trouble than it's worth. Thanks for the suggestion, though. I really just need a quick fix until such time as I can obtain a second, identical motor to butcher for spares.
It wouldn't be the end of the world if it started to leak a drop or two every 30 minutes ro so, since it is an outboard motor hanging off the back of a boat.
However, I reckon it should be possible to jerry-rig it so that it doesn't leak at all. Last time, I fixed it in with Araldite. It didn't leak at all - but it wasn't very strong either. The tap pulled out too easily. I reckon there must be some adhesive - or other goo - that will give some adhesion and be impervious to 2-stroke mix. Red Hermatite? Golden Hermatite? Superglue? Uhu? The fit is still pretty snug despite the lack of threads.
BTW, I'm not at all sure what kind of plastics the tank and petcock are. They may well be something other than polypropylene. Nylon, possibly. One thing's for sure: they look like the sort of plastic that's not easy to stick together!
You said late that the threads were damaged on both items. Could you not take the tap along to a machinists shop and ask them to clean the threads on the tap up or even tap it down to a slightly smaller thread size?
Then ask them to make up a brass fitting - like a threaded nut with a large flat shoulder on it. Cut out the treaded portion in the tank then fit the above with a soft washer impervious to fuel. In other words trap the tank firmly between the two parts.
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