Google: Is there a limit to shipping weight?

Google Merchant may invalidate items with shipping weights greater than 70 lbs.
In GMC > Settings > Shipping there would be an option to create a shipping rates based on a weight table or rule.

We suggest tinkering around with the shipping settings on GMC, where they regularly update their settings:
https://support.google.com/merchants/answer/6069284?hl=en