21HP Briggs Won't Start and Backfires stopping/reversing the engine

[rubantin]

21HP Briggs Won't Start and Backfires stopping/reversing the engine.. I'm thinking sticking valve?

Here is a video clip of it...

Will be up by 9:40PM CST

 

[motoman]

Start by removing the plastic cowling and checking spark timing. Many in the forum have found sheared flywheel keys allow the spark timing to drift. Usually after hitting something with the rotating blades. I don't know if there is a ref timing mark. On my Intek 24 I had to find TDC and mark it on the engine . Otherwise you might have to pull the flywheel to check the key. The big retaining nut is on with ?100 ft lbs of torque so you would need a tool to hold the flywheel while loosening the nut. Then a puller to loosen the flywheel. Others will surely chime in and help.

 

[EngineMan]

Yes check the flywheel key first. its firing when the inlet valve is open...! you should be able to see the key just by removing the nut, without the need to remove the flywheel.

 

[rubantin]

Thanks guys... will check it tomorrow...

 

[rubantin]

Well pulled the flywheel nut... not sheered... so, did something I should have done in the first place... pulled the plugs... the first one was clean.. but the second one... here is a pic

 

[EngineMan]

Burning alot of oil was it...! do a compression test on that cylinder.

 

[rubantin]

ok... replaced the plug... it starts but is not running on the other cylinder (the one with the clean plug)... seems like the intake valve on the other cylinder is "stuck". Only bought one plug. So, tried again with swapping plug sides... still only firing on the cylinder that had the gunky plug.... intake manifold blows back (no fire this time) with every revolution. This makes me think the intake valve is stuck open?

 

[rubantin]

Don't have a comp tester.. actually I do but we moved and it is buried in storage.

 

[rubantin]

ok.. took off the valve cover... bent rods.. figure it got too loose and came off.... can I just straighten them and put it back together?

Russ

 

[rubantin]

The rocker bolt hole is stripped.... ugh!!!