Threads are all chewed up and broken in places

should not be necessary but you do need to get an electrician top do the job

Difficult to diagnose without a machine brand and model. Is it a thread guide or the needle threader that is broken?

If the needle threader is broken, they are very fragile and are easily broken. There are moving parts associated with the needle threader so gluing may not be the best answer. However, it is not working anyway, so even if glue doesn't work, you will still be in the same position. You could take it for service, but that could be expensive.

The other alternative is to manually thread your needle--not such a big deal since that's how it's been done for 100 years... It helps to apply saliva to your finger and wipe it over the back side of the needle's eye. Then when you poke the thread toward the eye, the moisture helps draw the thread through the eye.

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the name & model number of the sewing machine is not shown
when a sewing machine sits up for a long time, sometimes the oil & grease can become break down & it does not take care of the machine like it should, & they need to be serviced once a year
the needle should be changed & the correct needle for the thread & fabric
it should be cleaned under the needle plate & in the bobbin area for loose threads & lint
the tension needs to be checked

I have seen this a couple times when the die begins to slide out as your threading it will turn enough to rip the threads just keep steady pressure on the wheel so the die cannot slide out if this is the case the other reason is normally because the dies were not installed properly take notice to the fact they are numbered

When threading the fourth thread (Green) make sure that the needle threads (1, 2 - Orange and Blue) are not over the fourth threader. This would cause them to tangle up with the fourth thread. This is caused when manually advancing the machine to thread the fourth thread. I run a piece of cardboard through the feed mechanism to free all threads before using the overlocker.

Ok,... before you re-thread the loopers, always unthread the needles.Thread the needles last.

no there is no solutions for plugging off the jets so the water doesn't go in them. you will have to pull the tub and repair the lines. no access panel just means you have to dig in!

What cutting compound are you using?

Yes, the semi-rigid metal flex tubing is recommended because it resists crushing, crimping, collapsing and heat. The old plastic flex hoses would collapse easily, develop more clogs, melt and rodents could chew through them easily. When installing a new flex hose, the SHORTER and STRAIGHTER you can keep the run, the better. The more bends you have, the greater possiblity you have of creating areas where lint can clog. I hope this helps you. Post back if you need further guidance.