First and foremost, do NOT go to the orange apron for advise on painting. Go to a real paint store where chances are the person who works there actually has painted something and most likely has some knowledge of paint an products.The employees @blowes and homely depot know nothing( for the most part)
As to you're problem, Zinnsers Cover Stain( oil) would be the best solution.
LIGHTLY sanding the existing paint will not damage the plaster in any way.
I would lightly sand, clean, and apply Bullseye 123 or Fresh Start.. There are many good bonding primers that will work to go from oil to latex ( with a light sanding and cleaning)

 

Ditto everything Chris says. :thumbsup: If you can still get it, I liked oil-based alkyd primers as great equalizers between oil and latex. You can put either over alkyd. Some companies are formulated alkyds in waterbased products now too.

As mentioned, good paint store quality waterbased bonding primers will work great too if you are finishing with acrylic products anyhow.

Oil finishes chalk over time so I cannot stress good prep over all else in your project!

 

Thanks so I just want to confirm... You think a latex/water based primer such as bullseye 123 will work fine if I clean all the walls well after patching and then sand the walls and then apply the primer and then paint... Right? Also will products such as bullseye take care of some staining/mold like killz claims to?
Thanks for all the help!

 

As the other guys have said, a good bonding primer is the way to go.

It caught my eye when you mentioned mold...

I'm not sure what, exactly, you mean. But do not just prime & paint over mold. You'll need to kill it first, and remove all of it that you can.

2 products I've used, and have had good success with, are Moldex and Microban. Bleach really doesn't do the trick. Spray the mold with either of those products, scrape & wash the area down, then do your priming and painting.

 

Absolutely correct. If you have mold or mildew issues you must source and deal with them before priming and painting. The commercial products mentioned should do the trick or even a bleach mix. However, if you have water pipes, drain lines or other plumbing issues or an HVAC condenser line leaking behind the lathe and plaster you had better cut out the damaged areas, fix it, then patch.

Kilz is not worth the can it comes in. If you have stain issues use a better stain blocking sealer/primer. For things severe like cigarette smells and tar stains BIN is the stuff to use. It is alcohol based though so make sure you have adequate ventilation.

 

Thanks for the info took care of the plumbing issues it was just the bathroom the previous owner had missing tiles and holes and didn't fix them yet still used the shower.. I fixed most of them also the house is at the beach down here in socal so I think a lot of it is just neglect as well as the moisture in the air... I will try some of the products you guys mentioned some of the stains could be from smokers but not quite sure I'll try to use a bleach solution do you think simple tsp will clean and kill the beach or is it pretty imperative I buy a more commercial product... The house was built in 52 and most maintenance was stopped middle of the 80's.... Luckily the house is on a raised floor so the plumbing etc is all underneath... I just finished removing all the original
Galvanized pipes that were so plugged up you couldn't even stick a bobby pin through them... Thanks for all the help folks!

 

Well I am glad you are trying to do things right. Quite a gift someone gave you if you have SCal beachfront property all of the sudden. I imagine it is well worth putting some money into it to correct 30 years of zilch maintenance. Sadly that level of inattention forces you to suspect everything.