I recently bout a 2005 Poulan tractor with a 17.5 hp B&S. i thought it may have been valve lash preventing it from kicking past TDC, adjusted that, which the exhaust was way off. Charged the battery and changed out the oil. still no luck, it hits TDC and stops. When Checking voltage at the starter it drops from 12.5 down to 5v. No luck even with a jump start. I got the correct manual in today and it looks as though I will have to tear into it to check compression release. does anyone have an idea?
Do a voltage drop test across each connection to find out where the resistance is. It could be the solenoid contacts are corroded but a voltage drop test will verify it. You should not have more than a .1 or .2 volt drop across a switch or set of contacts. Also check the voltage at the battery while cranking. Just because you charged the battery doesn't mean it has the capacity to hold a charge. How old is the battery? If the battery is original you may need to get a new battery. I did read where you used a jump starter but you can't rule anything out until it is tested and verified.
I forgot to ask if the engine is hydro-locked. Is it? You didn't mention if you removed the spark plug to check for anything preventing the piston from moving past TDC. Excessive carbon build-up? Other foreign matter in the cylinder? Can you rotate the crankshaft by hand more than 360 degrees? Did you do a compression test?
Yes, I checked for that, in fact the first thing I did was to check valve lash, check the plug, change the oil, and put the battery on a trickle charger.
If someone tries to turn it when it hits TDC it will turn over, but i need to check the battery also, as it is only a month old, then the voltage drop test.
I did get the engine service manual in so that should help some, we'll see what happens.
I have not done a compression test as my compression tester was stolen, doesn't seem hydrolocked, I took the battery back and the cranking amps were only at 100 when they should have been 330, got a new battery and it tries to turn over but then if I try a second time it won't. I am going to pull the starter first to check it along with all of the other wiring.
I already checked the valve lash and readjusted it as the exhaust valve had way too much lash. This did not clear up the problem, however I pulled the starter and although I am not able to do a growler test there were portions of the armature that had no continuity plus the magnets inside were no longer holding onto the housing. I plan to order a replacement because the brushes were also extremely worn.
