Air Conditioning - ac running overtime

i live in jville florida in a 2000 sq ft doublewide mobile home. my ac is set at 79 degrees and when i got home today it said room temp was 81. i checked the vents and the temp coming out was 55 degrees. it will cut on during the day and not cut off until night time. it is a heat pump system. i have goodair coming out of the vents its just wont stop. it only does this whn it gets in the 90s outside. when it is in the 80s it shuts off and on. wondering what could be the problem

What size is the unit? Is the filter clean?Is the outside unit clean?Are your windows closed tight?Is your attic vented?Shades /drapes on windows?

I just reread..you don't have an attic.What shape is your ductwork in?Your unit may be undersized and just can not handle the heatload. The temp out of 55 sounds good but may indicate a problem. A temp difference of 26 deg [81-55=26] is a high difference.Check for good air volume.

Mobile homes aren't very energy efficient. That 90+ degrees is attacking it from all sides incl the bottom. You might check this though....
Most have a large flex tube underneath that connects the AC unit on the A half to the other B half. Check that for holes, could be losing some air.

not sure the size of the unit. the air volume is okay. all my windows are shut and i have blinds and curtains covering them all. i did notice some vents on my roof that are different from regular vents to let hot air out. i have one in my sons room and it has a cover on it that says ventline and when i hit the switch it turns on and it seems like it acts as a vent to pull hot air out of the attic area. and there is also another one over my kitchen but dont have the inside part just a vent on the roof. i will for sure check the bottom duct under the house. ty for the feedback.

Manufactured homes always have ductwork problems. When you place your hand at a register, how far [in inches] is the air being blown? Measure the return air intake inside the house, what size is it? Read the label on the unit, post the model number and we should be able to tell you the size.

When it is in the 90's the unit should run well into the evening. Mine stopped at about 9 last night and it was in the upper 80's. I do agree that 26 is to high.

i am gonna bring a temp gauge home from work and check the air temp again. then im gonna check the duct underneath the house. i can sit on my living room floor and feel the air from the vaulted ceiling. i will look for the model # when i get home and post it. i think my filter is like 20x20 or a lil bigger.

i just checked my duct work under the house. the duct runs from unit over the middle of the house. all was clearuntill i got to the point where it goes up into the house. it has a y connection so i have 2 separate spots coming up side by side. the first was good then the second i felt some air coming out. it wasnt blowing out of there but you could feel the cold air. i wouldnt know how to go about fixing this because i dont know if it is lose in the wall or at the floor coming in. i couldnt see that much due to the flooring.