Rum mash will not ferment

[heresjonnie1]

Hi everyone,l
I recently made a rum mash from the recipe from Clawhammer supply and it will not begin fermentation. the recipe consists of 80oz molasses, 6lbs of natural cane sugar and 4.5 gallons of water. I warmed the water to around 120 degrees, added the sugar nd molasses and mixed/aerated wit a drill with a paint mixer attached. I let it sit covered overnight and then made a yeast cake from regular Fleichmens yeast and added that to the mash. 24 hours late I had no fermentation, so I aerated again, covered and waited another day. Still no fermentation. So I made another yeast cake and tried again. Following day, nothing. I store my mashes in my outside shed, so I checked the temperature of my mash and it was 75 degrees, so I don't think temp is a problem. I've made this recipe a couple of times before without problems. Buckets were clean. When I added the yeast I did notice that it kind of fizzed. Is the sugar content too much for the yeast? I don't remember if I used distillers yeast when I made it last. Any suggestions?