I was living with my run-lean-on-warmup problem until Gernold adjusted my linkage to eliminate the early movement of the pump lever. After that, the start-die and driving while warming up got much worse as in terrible. The problem is that the pump just wouldn't deliver enrichment with a cold engine, despite the air part of the WRD working properly.
So, I talked to Hans at H&R injection about rebuild prices. I described the problem, and he asked me if I had checked the oil in the pump. I said, no, I thought it was fed off the line from the engine and there was nothing to check. He explained where the dipstick was. He said the oil needs to be checked and changed periodically. He wanted me to look for gas in the pump's oil, which would indicate worn seals and the need for a rebuild.
I did a search on this and found an excellent post by Arthur and others. Arthur explains that on the 230 and 250 pumps, the oil from the engine lubricates the shaft seal, and that the pump has it's own little sump.
http://www.sl113.org/forums/index.php?topic=4199.0So I found the dipstick, a 14mm head with a screw notch just under and to the outside of the solenoid. As soon as I removed it, dirty oil started gushing out into the pan I put under the car just in case. Then I used a tube from a Windex bottle and my MityVac to suck out the rest. There was 3-4 times as much oil as should have been there.
The good news was that it did not smell of gas, it was more like really dirty engine oil.
This morning I refilled with about 175 ml of 10/30. Things aren't perfect, but much better. The car was quite driveable warming up, smoother and more responsive. Apparently, excessive oil impedes the flywheights and generally screws up the internal working of the pump.
Maybe I am the only one who didn't know about this aspect of the pump, but thought I would post it anyway.
