Graham R wrote:
Engineering solution? As a matter of interest, the hinge pin looks like it's a rivet of some sort, rather than a proper pin; how sloppy is that rivet in either half of that bracket? Any slop will result in the pressure from the "black thingy" not being enough to hold the base in the vertical position. Even if it is just a slightly sloppy fit, then replacing the rivets with countersunk bolts/ locknuts, possibly in conjunction with plastic bushes could improve it. You would then be able to adjust the hinge friction as well; using a thin plastic washer between the two hinge faces to prevent wear of the coating on the contacting surfaces.
I think Graham is on the right track with this suggestion. But it was also noted that the black tensioner might also be an issue. Perhaps a combination of efforts would be ideal. Replace the black tensioner (or whatever it's called) and also the hinge pin. I'd start with just the tensioner and see if it helps enough. Replacing the hinge pin would be a bit more problematic because of the way cushion above it has to straddle the hinge arm. Any protrusion would raise the potential risk of wearing out the vinyl on the cushion. Some sort of cap or shield on the replacement fasteners would seem like a good idea.
I don't know that grinding down that surface would be the right choice. I don't have a seat like this so I can't really say for sure. But in looking at what appears to be a wear pattern, the arm actually NEEDS the length of the arm. Removing that portion looks like it might make matters worse. But, again, I've never seen this sort of assembly and I'm just going off that one picture.
I would suggest that assembly is not made by FW. Most parts aren't. I'd contact the factory and ask who makes it for them. That company may be able to offer better solutions to the problem.
Also consider asking a local boat upholstery shop. Seems like something they'd have dealt with in the past.