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Discussion Starter · #1 ·
I have run out of things to try!

Have a Briggs 18.5 hp 31p777 that has been hard cranking since new.

It cranks to compression then won't go past.
I have set valves .005 and .007 cold, removed head to clean carbon (not much there), removed flywheel and checked key, set armature gap .012.
Still won't go past compression. Installed larger CCA battery, jump with Ford Super Duty (2 batteries and #4 jumper cables) still stops.

Hooked #4 jumper cables direct to starter, just heats up the starter and cable and won't turn past compression.

To start I just keep trying and eventually it will roll past TDC and crank normally and start. Then starts normally the rest of the day.

I have even looked for a compression release to no avail.
 

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Its possible your compression release mechanism might not be working properly, but i would start with checking your starter first, if its drawing too many amps it will not crank over fast enough and the cables will start to heat up.
 

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Discussion Starter · #3 ·
compression release mechanism

Starter draw ok when I get it to crank but high when trying to start aginst compression.

? where is a compression release mechanism? Can't see it in the manual.

Thanks.
 

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Compression release is on the camshaft. The easiest way to check it is to remove the spark plug and valve cover then watch the valve operation as you slowly rotate the engine, one of the valves should open slightly near the beginning of compression stroke. If neither valve opens then recheck lash. Be sure to check valve lash at 1/4" past TDC on power stroke. If lash is good and you cannot detect any compression release operation, then the engine will need to have the sump removed in order to inspect the compression release mechanism on the camshaft.
 
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