Our toilet will not flush all the way. We tried shortening and lengthening the chain and that did not help. It looks like the flapper is closing too soon. How can I fix this? Or Do you think this is even the problem?

Please explain your complaint in more detail. Does the flush cut off too short?
Does the bowl fill up, swirl around and drain slowly down leaving solids behind?
Back to you. Regards, Tom

The flush cuts off too short. If we hold the handle down we can get it to flush all the way-- but I would prefer to just push it down and let go :)
Solids will be left behind if I do not hold the handle down long enough.

New toilets are like that to save water, u have to hold it down for a long flush

This is not a new toilet.

This is not a new toilet and it's not even flushing enough to get the waste out of the toilet.

Snake toilet complete
Time to replace all of the tank parts or the complete toilet
Get r done:)