Small Engines (Lawn Mowers, etc.): New starter, still hard to turn over, deep cycle battery, engine cranks

Question
QUESTION: Hi,
I just bought a used Murray 40631a with a 28V700 Series 12.5 hp B&S engine.  The engine would crank (turn over) slowly when assisted with hand on top.  Btw, this is with a new, good, deep cycle battery jumped directly to it.

After some research, I bought a  replacement starter as turning it by hand alone, it feels smooth, can hear/feel compression and oil looks good.

It turns a little better now but still stops every cycle unless I assist by manually turning the top.

The engine ran last year and doesn't appear "siezed", what am I missing?

Thanks in advance
Travis
ANSWER: Hello Travis:

Set the Piston to TDC. Reset the Valve Clearance. Set the Intake at .002in - .004in and the Exhaust to .008in - .010in. The Compression Release is Not Operating Properly because the Valve is Out of Adjustment. This is a Common Problem with All the OEMs  Engines; Wether its a Briggs, Tecumseh or Ect. They All are having this Problem. Also a Damaged Flywheel Key will Cause the Symptoms you Described. Hope this Helps. I am Here if You Require More Assistance. Let Me Know What Happens, Please. Thanks.

Good Luck

Respectfully  

John

---------- FOLLOW-UP ----------

QUESTION: Hi and thank you for such a quick and detailed response.

I removed the spark plug and engine cranks normal speed and even started within seconds after replacing plug.  But after killing it, it wouldn’t restart.  So I assume that verifies it’s a compression issue (since I released it with plug removal) and not fly wheel key.

I've done timing belts, water pumps, engine/trans replacments but never a "valve job".  Are the measurements you gave the gap between the fat part of the valve and the valve seat or the bottom of the valve shaft?

If you would verify that, I'm confident that between the B&S IPL and google, I can handle it from there.  Thanks again for such quick, expert guidance.

Sincerely,
Travis

Answer
Hello Travis:

The Valve Clearance is Between the Valve Stem Top and the Tappet. A Special Valve Spring Compressor will be Required. Once you have Seen the Breakdown/IPL and are Sure you want to Attempt this Repair; Let me know and I can Give Detailed Instructions. The Breakdown/IPL is at this Site Addy, http://www.outdoordistributors.com/ and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File #28. then Select the Folder #28V700. Hope this Helps. I am Here if You Require More Assistance. Let Me Know What Happens, Please. Thanks.

Good Luck

Respectfully  

John