A friend dropped off a machine that wasn’t running. He had used dirko on a carby gasket which blocked the impulse. Here is a picture of how different sealants react to fuel after a few hours.
The only one that really stands up to fuel is Motoseal (left which I had to use my nail and pick at it to remove it) the others are ThreeBond 1104, Yamabond 4 and dirko all are affected. ThreeBond dissolves, Yamabond and dirko swell and crinkle.
i’ve mentioned before that used correctly they’re fine, but be very careful if you use them as a dressing for gaskets both due to blocking holes or swelling into the intake.
A quick repair in this case, but thought I’d share a pic here. The only dressing compound I use for gaskets is either hylomar or aviation form a gasket. Both of which don’t react to fuel. You could use Motoseal but you’ll rip it on disassembly.
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