Hello,
Mine does the same thing and even does it when I jump it with my truck. I know the battery is about shot. Is it possible to have a weak starter motor? Never adjusted the valves because I don't know how. I would hate to buy a new battery and not fix it. The mower was a freebie so you can imagine its not in very good condition at all so I really don't want to spend a lot of money on it. Can you explain how to adjust valves? The motor is a Briggs 16.5 HP
I know this is a bit late but I wanted to put some feed back on this as I have worked a Toro LX500 that has a Kohler Courage sv720 in it. Her's was having issues with getting over the compression stroke as well so here is what I did:
1. Had battery tested at Oriellys and checked the solenoid, both were in good shape, but still had issue with compression stroke
2. Tested voltage at starter - was 12+ volts.. this was good.
3. adjusted valves to specs, first and cheapest adjust to see if it fixed it.. It didn't
4. Verified the engine spun easy with ignition by leaving spark plug out - It spun really good
5. Found that one of the magneto coil spark plug wire was partly chewed through by rodents, replaced it and that didn't help either.
6. Had to replace the regulator as that wasn't working but that shouldn't affect starting or compression stroke issue.
7. While re-testing the startup again, the start literally started smoking and burnt up and started smoking
8. replaced the starter.
The starter was the ticket. The lady stated that the other start was only like 1 or 2 years old. BUT the mower stays outside and for the most part is under cover but still in the elements of hot, cold & moisture. My guess is it was either combination of cheaply made parts or elements got to it or both.. Not sure which but the new starter cranks the engine right up now. The old starter just got weak on the bushings and coils to turn the engine over the compression strokes of the twin cylinder sv720 engine. I hope this helps other decide on what to try. I know that I read a lot about the compression release on the cam shafts getting work down but I would MUCH rather spend 30 buck and try an easy fix like that rather than pulling the engine off and tearing it apart to replace about a ~100.00 cam replacement. Please do you research before you just go out and by parts.
So to answer your question about, "Is it possible to have a weak starter motor?", the answer is YES. I have run in to this on more that 1 occasion. The other occasion was on a my briggs & stratton 31p777 motor. You are the first person that I have found to question the starter. All of the other information I have seen on compression issues is people jump right into the whole, "It's the compression release on the cam shaft" statement. Not even suggesting the starter may be too weak to get past the compression stroke.
I hope this helps others who run into this situation of an engine not being able to get past the compression stroke or getting past it but having a very hard time doing so.