Small Engines (Lawn Mowers, etc.): problem with engine!!!, car quest, load test

Question

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Followup To

Question -
Hi John,

I bought an craftsman 18h.p. b&s lawn mower brand new about a year an a half ago.  the starter now seems to be having trouble cranking the engine.  I used to be able to key turning the key back and forth util it finally cranked, but now that don't seem to work very well now.  If I pull the spark plug out it cranks fine.  battery has 12v. is this some sort of combustion problem.
hope you can help..

Answer -
 Hello Adam:

 Load Test the Battery. Just because the Voltage Shows 12VDC Doesnt mean the Battery is Good. A Load Test will Show what the Battery Does when Under a Load. If the Battery has a Weak Cell it will Show 12VDC but when a Load is Placed on the Battery, it will Drop to 8VDC or Less. This Isnt Enough Voltage to Properly Turn the Motor. If the Battery is Good, then Check the Starter. The Brushes in the Starter or the Bushings will Cause the Starter to Drag and Turn the Engine too Slow. The Starter can Be Draw Tested for Bad Bushings or Brushes. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John

I tested the load of the battery and it did drop to 8vdc when try to crank the engine. I charged the battery for a while now it drops to 9vdc while trying to crank.  I also did a compression test and it came back at 160psi every time.
is this a bad battery?

Answer
 Hello Adam:

 Testing the Battery the Way you Did is Not Going to Tell you if the Battery has a Bad Cell. If the Starter is Dragging it will Draw the Battery Down as you Described. If you have Jump Started the Mower from Another Battery and the Engine Turns Good then Remove the Battery and go to your Local Automotive Parts Store and Have them Load Test the Battery. I know tha NAPA and Advance and Car Quest can Load Test the Battery. If using Another Battery the Engine Turns the Same, then the Starter is Dragging. Also, If you have Been Having to Turn the Key Back and Forth Until the Engine Turns Properly, Take a Jumper Cable and Using Only the Positive Lead Attach One End of the Jumper Cable to One side of the Starter Soleniod. Take the Other end of the Jumper Cable and FIRMLY Touch the Other Side of the Starter Soleniod. If the Engine Turns Properly, then Replace the Soleniod.  If the Engine Does Not Turn Properly, then it's the Starter Dragging or the Battery. I see I forgot to have you Do That Test in Or Last Email. Sorry. Also, Remove the Belts from the Engine Pulley. Just on a Chance that a Bearing has Locked up on the Mower Deck. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John