Maybe someone can help me figure this out.

I'm only getting 18mpg on B100. 75% of my trips are 45-50mph with no stop lights. Even taking off 10-20% for bio, I think I should be in the low 20's

Had a bit of smoke on startup, so I ordered a new set of Monark injectors from Mr Watts. The first time I started it after installing them, the engine was purring like a kitten. It was as smooth as our 606 engine.

The next day, start it up, idle is a little rough. Day after that, the idle is as rough as before. I though there was a clog in the system and maybe it's sucking air. Changed the primary fuel filter (it was clogged). Seconday filter was changed a couple months ago. To rule out the tank strainer, i've swapped the return and supply lines. Still has a rough idle.

I'm thinking the poor economy and rough idle may be the same issue. I can't figure out why it ran so smooth the first time I started it.

I'm going to run the tank down and remove the strainer and also change the secondary filter again.

Any ideas?