Hi Tom
I've been running a single cylinder Hatz all summer - about 700 hours, so far - with 20% filtered wvo. I discovered a bad attack of diesel bug last week end, the exhaust is a bit sooty, other than that, no problems.
Here's a good, concise brief on diesel bug
https://conidia.com/diesel-bug/#1576146601791-21bb4c02-2c33The diesel bug contamination is almost certainly lack of attention to detail on my part, I just didn't give it a thought.....
The tank is in a lovely warm spot, next to the genny and veg oil is a great source of vitamins for the bug, it was almost bound to happen
I'm using red diesel / heating oil that had sat in an underground tank for a couple of years, I've now had a good clean out, new filter and am conditioning the fuel with a proprietary marine additive, I'm also looking more closely at what's in the ready use tank!
Somewhere on here, someone posted the results of a lubricity test in the US, I think, with with proprietary additives, and straight soya oil was as good or better than almost all of the competition and way cheaper.
I would say, as it's going to be a standby unit, add a little, 3 / 5% veg oil for lubrication and a fuel conditioner for protection.
A valve in the supply from the tank allowing to you to draw off any condensation at the bottom of the tank and check a small jam jar of fuel would be a worthwhile addition. as would a CAV 296 type filter with a glass (see through) sediment bowl.
Cheers
Stef