bio-d causing loss of power in 3yr old svo truck, makes no sense

[tim594]

System:
2000 Ford f350 7.3L.
Ive been running SVO for 3 yrs no problem.
2-tank, coolant heated system, hose-in-hose,
copper coil heater in svo tank and svo filter.
6-port switch in front of stock pump along frame under drivers door.

Just started burning Biodiesel:
The first time, I put B80 in my main unheated stock tank.

Then, within 1 day, had powerloss at ~2500 rpm, it would run rough, no power, and sounded/felt like when you change your fuel filter and you have air bubbles in the system.

I thought it was the filter, so i changed it, didnt help.

Switching to SVO tank solved the powerloss problem, which means it wasn't the filter.

So, I continued driving and burned a half a tank and added diesel to dilute the Bio, so now its down to about B50... but still has the problem!

Problem details:
Start the truck cold - it runs rough in idle. (Im thinking that the Bio settles to the bottom, so its getting B100 at first, until it warms or mixes a little)

After warming up for 5mins, it idles fine, and revs to 2500 in Neutral no prob.

I drive for a few miles in low RPM's, its ok, but as I start going on the freeway about 60mph... but after 10-15 mins, I get powerloss at 2200.

If i stay on the gas, it gets worse, and I can eventually only go 40mph.

If I let off the gas a little and cruise at 40 for a while, then im able to go 60mph again for a few mins, before the power loss kicks in.


Ideas:
The only thing I can think of is:
1. the bio dislodged some gunk in the tank or fuel line from the tank to the svo switch, and clogged it. (But this doesnt really make sense, since it happened almost immediately, the same day, when i put the bio in.)

2. the bio is a bad batch and is actually svo (im checking with my source now).



IF, it is #2, what can I do? Do I have to drain the whole tank, or can i mix in some thinner?



Thank you,
any input is greatly appreciated.

[ned37]

siphon some out and take a look at it.

[redtopman]

Just a guess. Since it runs ok on SVO you might check the stock check valves. Could have some gunk in them.

[hheynow]

Blend in some #2 or kerosene and re-check your power.

[kevinj1]

If you have separate fuel pumps check the PSI of your BIO tank pump

[wdwkr]

When I have had a loss of power it was the fuel filters. They even looked fine but when I changed them it made all the difference in the world. Do you know where the Bio came from? It could be bad. My school of thought is to start will a very low % of bio and work up to B100. There seems to be more problems when just starting on B100 the first time. It will clog the whole fuel system up if there is a lot of sulphur build up in the tank and lines.