Engine is a B&S model 404577 0291E 031208
The challenge is when the engine is turning over to start, it turns as far as Top Dead Centre, then stops.
With the starter engaged, you can twist the fan to get it past TDC, and then it will continue to spin over and start.
Customer has installed a new B&S starter, and it checks out ok.
I have disassembled the engine thinking that there may be a problem with decompressor, as was the case with many of the singles.
The unit doesn't even have a decompressor.
I have adjusted the valves upon reassembly of the engine to slightly lower .004 clearance.
Battery is a 340 CCA and new.
I have replaced all battery cable connectors and soldered in place.
I have buffed up all chassis grounding points for negative cables.
Finally, I have run an extra cable directly from the - terminal of the battery to the engine block.
After 40 years fixing theses things---
What have I missed?
A little help is needed.