Does anybody have a diagram or any tips for this knot ive watched a couple youtube videos on how to tie it and when i then test the knot strength it tends to snap at the knot realitvley easy making me believe Im tying it incorrectly or making a simple error. If it some how helps i way using 17lb fluro to test the knot

http://www.animatedknots.com/sandiegojam/   Wet your line.

Wet your line and tie it slowly. you are probably tying it incorrectly or maybe bad line. I've been using that knot and that knot alone on fluoro for that past few years and can't remember a breakoff due to knot failure. 

Make sure you wet your line with saliva.

If you have a smartphone you can download load the knot wars app, too.

i have been wetting my line but i think iy may be the line because it was some i had left from an old 1000 spool i bought at the begining of last year btw what is the most effecient way to test knot strength

Download the app fishing knots to your phone. This is my favorite knot. With flouro remember to wet and slowly tighten making sure the wraps to not over lap each other. That is the key.

So i just played an experiment with the breaking strength of the san diego jam knot on 15lb invizx it averaged out to break at around 11.5-11.11 pounds does the sound right to anyone? When it comes to knots i am very concerned on strength because when it comes down to it landing a fish all depends on the strength of that knot

Hopefully WRB wil chime in on knot breaking strength of fluorocarbons. He can give better specifics than I can. Fluoro loses a % of its breaking strength on the initial first tying of a knot but i don't remember how much. 

That's 75% of 15lb test so it's about right.