[spuggy]

Wow, can't believe it's taken this long. My excuse is that the garage has mostly been impossible to go into - like 45C during daylight...

But sucked down coffee and made it in there today before it got too hot...

TL;DR:

To fast-forward to the chase; the fuel line between pump and filter had completely lost integrity. In my efforts to dislodge the pump from the #$%$#% clip in the tank, I could see most of the outer rubber part of the hose had fallen off, completely exposing the cloth braiding.

By the time I worked the pump out, the only thing connecting the pump and the filter were the fibre braids; all of the rubber vanished entirely. I could hear the chunks hitting the inside of the tank.

Longer whinge:

So, Public Service Announcement. Pardon me if everyone but me already knew this, LOL...

I didn't fully appreciate until I did some googling to buy replacement hose a few weeks ago (it was obvious I was going to have to split the hose ends with a razor to get them off, as they acted like they'd bonded to the tank fitting), but injection-rated fuel line from an auto parts supplier will almost certainly be SAE 30R9 (high pressure). Carburettor fuel line is rated SAE 30R7.

However, SAE 30R9 has no business going ANYWHERE near the inside of an injection Monster fuel tank. Because what you want is submersible fuel hose, or SAE 30R10 rated (or higher).

30R10 is 4x, 5x the price of 30RJ9 - and this is not what you're going to get unless you specifically request "submersible" fuel line.

This is the second Monster I've encountered where the internal high pressure hose in the tank was something that presumably wasn't the correct stuff - and the hoses have waited until my ownership to fail.

Pretty happy I found the problem, at least...