All the plastic parts jets and their housing turned yellow

I can only suggest that you ,first post what your working on. Then post it to the right category. Even though car mechanics work on many different motors and such. I don't remember any black button on a yellow housing. Maybe John Deer tractors?

Yellowing is a sign of age, but plastic items can be brightened up a bit. Here are some suggestions:
http://www.howtocleanstuff.net/how-to-whiten-yellowed-plastic/

Gear lube part # 92-858064Q01 is (32 fl oz) plastic bottle Quicksilver Branded, (Try Rechecking your wal-mart for Quicksilver part number 92-858064Q01). Or if you want a lot more oil, there is Part # 92-858065Q01 is 9.46 L (2.5 US gal) plastic bottle Quicksilver Branded.This SAE 90 gear lube features improved emulsifiers to help protect gears should water enter the gear housing and tackifiers to improve oil film adhesion to gears and internal components. There are extra additives to protect gears from metal to metal contact and excessive wear. Quicksilver High Performance Gear Lube is recommended for use in
outboards, Jet Pumps and Sport Jets above 75HP and for all sterndrives

sounds like you need a new seal kit if it is leaking between the plastic pump housing and the motor. this seal kit is a model PS-200 and will run you about $30

US Parts Center

I am not sure if you have figured out how to put the chain back on your saw or not, but it doesn't take long.
1. Remove the plastic yellow "T" shaped nut on the right side of the saw (towards the front of the motor housing)
2. Remove the black plastic housing that covers the rear section of the bar and chain
3. Place the chain back onto the bar making sure it is facing the correct direction.
4. Place the chain over the rear sprocket area
5. Turn the +/- yellow plastic knob (towards the back of the saw on the right side) in the - direction until the metal guide inside the plastic casing lines up with the hole in the chainsaw bar
6. Replace the black plastic housing and slightly tighten the yellow "T" shaped nut.
7. Now turn the +/- knob until the chain is tight. Once the chain is tight, turn the "T" nut until it is tight and you are ready to cut again.

Try Guillens.com or usparts.com I have had some good luck finnding jets. Maax is still in business and you might be able to get the jet directly from them, although they are in Canada. Hope this helps.

The jet bores are supposed to have a plastic liner near the outside of the bores that grips the jet screws to hold adjustment. You could try inserting a piece or two of thin plastic fishing leader, then inserting the jet screw. Don't insert so much leader that the material gets into the pointed end of the screw area as it will plug the jet. Any other threads that are not holding after being properly tightened can be be restrained by applying 'Loc Tite' thread locker fluid (from an auto parts house) to the threads before putting things together. Does the machine seem to have excessive vibration? Investigate the problem if it does. Hope this helps!

Had the same problem and it turned out to be an obstruction in the nozzle and I mean a small obstruction, it looked like an ant leg. I pushed a 1mm drill bit through and now it works fine.

you would have to contact flotec----there should be a part for it,, depending on the age of it, they change the covers all the time to get people to have to replace the whole unit

Check the jet pump, also where the filter is there are two 90s plastic. make sure that they are both in the water, if all those check out then check the switch for the jets. It sounds like the pump is bad and is not pumping the water. Even if the motor works and the internal parts of the motor seal gets wet then it all needs to be replaced and rebuilt. Very easy to do yourself. Like always be careful and unplug the unit.