Game Boy start button trouble!

I have an original Game Boy and 2 Game Boy Colors, all with the same fault: they each have a double-pressing start button.

I only know of 2 games which are affected by this fault: Mario & Yoshi (Yoshi in the US, Yoshi's Egg in Japan) and R-Type.

On many attempts to pause either of the 2 games mentioned above, the game unpauses itself straight afterwards. It happens quite a bit on my original Game Boy, on my grape Game Boy Color the rate is similar, but the clear purple Game Boy Color is the worst affected.

Any suggestions for a fix?

I know I can find replacement rubber contacts for the Game Boy Color easily, but replacement rubber contacts for the original Game Boy are IMPOSSIBLE to find! >.<

 

Try cleaning the rubber contacts, make sure if there's not a single thing that is sticking it (maybe there's spilled drink or something).
I had this problem with a PS2 controller, I only cleaned the button and it was working properly again.

 

Not only that, but clean the contacts as well. Most of the time it will fix the issue at hand. clean the rubber portions, and the onboard contacts. You should then be rolling down da streets wit yo gameboy =P

 

Had a similar thing with my SNES controller. The start button was highly unresponsive. Took the controller apart and cleaned all the contacts (so much dirt!) and now it's working perfectly.

 

The rubber pads can wear out as well. The way the pads are made allows them to spring back into shape; however, over repeated abuse, they lose springy-ness and sometimes even separate. To be clear, I am talking about the rubber that surrounds the black circular pad.

Another issue could be a severed trace on the motherboard. With the system open, look for shiny metal scratches going across the normally covered circuit (green lines).