A few things can cause a cartotank to leak. Overfilling the carto during priming the carto can do this (pretty hard to do this in my opinion) or
getting juice in the center air hole can do this, too. I gently put part of a
wood toothpick into the air hole to prevent juice getting in there. Then there's no need to blow out the carto hole after finishing the priming process.
You're not
filling your tank with the top cap off, are you? Only fill the tank fully assembled, and through the hole in the top cap of the tank with the carto half way hanging out the bottom cap. Only fill the tank 80% full.
Are you sure the tank or carto is really leaking?
A drop of condensation from vapor reconstituting into liquid from the drip tip and air tube is quite common and ends up on the Provari's connector pin. Just clean the connector pin area with alcohol on a Q-tip applicator.
A
worn or missing inner o-ring in the tank caps can cause leakage. IBTanks provides extra o-rings with a new tank, and more replacements are available on the website.
Are you using a tank tool? IBTanked provides a combination drip tip and tank tool with their complete tank kits. An even better tool is the Slap Yo Moma tool from Big Daddy Vapor or the tank tool from Valley View Vapes. Not only will one of these make filling/assembling your tanks faster and easier, they also protect your tank's inner o-rings from damage by inserting a cartomizer.
I consider one of these tools indispensable. A PBusardo Review - Slap Yo Mama Multi-Purpose Adapter - Big Daddy Vapor - YouTube
You may need to
adjust your vape draw. Pulling too hard and short increases the amount of juice wicked from the tank that can lead to flooding. A more gentle and long pull works best for a cartotank. Imagine sucking on a straw in a milkshake (but gentler).
You may need to
adjust the number of holes you use in your cartomizer to match the viscosity of your e-juices. Smoktech tank replacement cartos can be purchased with one, two, or three holes that are laser-drilled. Use one hole for thin juices, two for normal, and three for thick juices.
http://www.e-cigarette-forum.com/fo...nched-single-coil-cartomizers-cartotanks.html
"When I turn the volts up to 4.4 and higher I get a burnt smoke flavor." Seems simple to me to just not turn the voltage up higher than 4.4. I use 2.5 ohm Ikenvape Platinum and 3.0 ohm Ikenvape 510 Fusions and rarely go over 4.5 volts on my Provari's. What's the point of going higher? Just because someone else has said that they use voltages higher than that does not mean you need to. Find your own sweet spot with your individual flavors and personal setup.
Although often said to be used only as a general guideline, the Safe Vaping Power Chart suggests not going higher than 5 volts on a 3.0 ohm carto. Your particular juice flavors may just taste better with less than 4.5 volts; adding more volts may cause them to taste burnt on your current Provari/cartotank setup.
To ensure you are priming your cartomizer and filling your tank properly, I suggest browsing my cartotank setup guide. There's more than one way to set up a cartotank, but you've had issues and maybe you will find a different way works better.
http://www.e-cigarette-forum.com/forum/blogs/baditude/3710-5-cartomizer-tank-setup.html
There is an admitted learning curve to using cartotanks initially. A little knowledge, experience, and a solid methodology of filling one goes a long way. Be persistant and it will come. The most important step is priming the cartomizer properly; how well you do this will determine how well that carto will perform for the life it has in the tank.