Got the shop waste oil furnace operating fine again. Turned out I was at fault when I changed the filter. Thinking I could use any old oil filter....well, ya can't! I ordered proper filters, 2 so I'd have a spare. These use "screen only" filters, and any with paper in the element will clog soon. I got to thinking how the problem gradually became worse, then did some checking. When I seen the proper filter was only screen mesh, I knew I caused the problem. I could never see air in the suction line, so ruled out the check valve, so the air was coming from the pump shaft seal under such a vacuum from the clogged filter that it pulled air past the shaft seal. Changed the filter out after feeding silage, and now it seems to be operating perfectly.
Heading out to go SUV shopping. There are a few in my price range, so want to go while the places are closed to look without a salesman pressuring me. No, can't look inside them, but going to my grandson's Birthday party that will take me past all these car dealers, so knocking down a couple birds with the same stone. Looking at Mercury Mountaineers mostly. They don't get the best mileage, but they have the power. The V8 version gets pretty much the same as the smaller V6, but have 82hp more (210 vs 292hp). Being I pull trailers kind of often, I could use the power. Avg mileage of 16 isn't good, but lots of owners report 22mpg highway, which is as good as my Cherokee can do.