Briggs 8hp hard to crank over manually, ok electrically.

[KE4AVB]

With the addition that the starter is actually having problems getting pass the TDC compression stroke at times I would say it is a compression relief problem. Plus considering it is a '71 model I say it is likely a worn camshaft then.

In order to replace the cam it would take one from a donor engine since Briggs no longer produces this camshaft. 211689 > 691167 > NLA

You ask if possible to add a decompression valve. I have never seen one done on these engines before but it might be possible. It would require modifying the head to where a decomp valve could be installed. Just don't what the maximum compression one of those valve from a chainsaw can handle. I do know some of them are exposed to around 150 psi. It would be interesting experiment.

[Arkie]

You ask if possible to add a decompression valve.

I briefly searched around about such online and did not find where anyone had tried a add on compression relief valve to a 4 cycle engine head.

Was surprised that a redneck had not done a you tube about such.

[Arkie]

With the addition that the starter is actually having problems getting pass the TDC compression stroke at times I would say it is a compression relief problem. Plus considering it is a '71 model I say it is likely a worn camshaft then.

In order to replace the cam it would take one from a donor engine since Briggs no longer produces this camshaft. 211689 > 691167 > NLA

You ask if possible to add a decompression valve. I have never seen one done on these engines before but it might be possible. It would require modifying the head to where a decomp valve could be installed. Just don't what the maximum compression one of those valve from a chainsaw can handle. I do know some of them are exposed to around 150 psi. It would be interesting experiment.

Redneck test: (and fix)
I got some time to make a redneck test install of de-compression release of the 8HP Briggs.
I installed a de-cpmpression valve into the head of the old 8 HP Briggs that parts are NLA due to age and it works great. (easy crank and start) I had to carefully select a place in the raised part of the head by the valves, spark plug area.



I used this one for chainsaws from Flea bay.

M10x1.0 Easysaw Decompression Valve For Husqvarna or Stihl fits most models