Newly installed jacuzzi only has hot water for about 30 seconds, then water is tepid only.

SOURCE: Jacuzzi tub works.....sort of.

motor for tub does not run checked electric its ok.. is there a reset button and does there have to be water in the tub?

SOURCE: Leaking pipe in a jacuzzi hot tub

The only product I know of which will do what you ask is an item called Plast-Aid Acrylic and PVC repair kit. Google it and you will find the website. It is about $20. and it works like a charm. good luck

SOURCE: Jacuzzi Hot Water Heating Capacity

Depending on how you heat the hot water, whether gas or electric, is a missing detail in your problem, but if it is electric then your problem is the size, being only 40 gal, and needing probably about that to fill the tub, will always lead to your current position.
If the hot water heater is gas, the chances of it keeping up are slightly better, but again things like the temperature of the water leaving the tank, any mixing valves, etc. will effect the water temp at your tub.  Before raising any temps, make sure you follow local code, as not to scald yourself or others.

SOURCE: water leaking due to faulty knob on jacuzzi whirlpool

replace rubber wasers

SOURCE: Faucet placement on Jacuzzi 6036

If there is room most definitely you can place the faucets on the tub itself. You can mount them on the left rear. However be very careful drilling the holes and make sure you have it aligned correctly before drilling. Check underneath to make sure there is enough room for clearance and hook up. Here is what it will look like.