Old Briggs compression test readings

[ricklea1953]

I have a 1963 horizontal shaft 6 cu in Briggs and Stratton. I have no spark yet and would like to check the compression before I proceed with more repairs. I have read that Briggs and Stratton do not publish recommended compression test readings.

What ballpark reading should I be looking for? I have read online articles recommending readings from 60 - 90 psi?

What range should I consider adequate before deciding whether or not to continue investing in repairs on this engine?

Thanks

 

[briggs]

I have a 1963 horizontal shaft 6 cu in Briggs and Stratton. I have no spark yet and would like to check the compression before I proceed with more repairs. I have read that Briggs and Stratton do not publish recommended compression test readings.

What ballpark reading should I be looking for? I have read online articles recommending readings from 60 - 90 psi?

What range should I consider adequate before deciding whether or not to continue investing in repairs on this engine?

Thanks

60 to 90 is good ...There is a trick i learned many years ago by one of my shop teachers....pull the plug out place your thumb over the hole and have some pull it over if it i pushes your thumb off the hole its good it even says that in haynes repair manual ...I use this trick when i am out on service calls i dont always have my comp tester with me on the road

 

[DaveTN]

Another procedure I use to test for compression other than finger-over-the-hole method mentioned is to leave the plug in and pull the cord to see if I have normal compression resistance. This only works on the older type engines or the ones w/o the "compression release" which won't get compression until a certain rpm is achieved. Otherwise we couldn't pull the engine over to start them. The points on that old engine are of course under the flywheel and that may be why it's not getting spark. Clean and set the points and before you tighten the flywheel nut down tight, just give it a spin and check for spark. Or put in a new set of points. But before you take the old points and condenser out, clean them, set them and see if you've got spark.

 

[ricklea1953]

I finally got around to the compression test; lots of overtime this week.

Initially, I got 50psi which I think is on the low side. Then I sprayed wd-40 into the cylinder and I think I ruined my compression tester because it read zero. Next I poured a little motor oil in and there is a noticeable increase of pressure on cranking. The tester still reads zero but I can feel a lot of resistance when pulling the rope.

What should I learn from this? Should I pull the head to see what things look like and install a new head gasket to see if that helps?

Thanks

 

[briggs]

I finally got around to the compression test; lots of overtime this week.

Initially, I got 50psi which I think is on the low side. Then I sprayed wd-40 into the cylinder and I think I ruined my compression tester because it read zero. Next I poured a little motor oil in and there is a noticeable increase of pressure on cranking. The tester still reads zero but I can feel a lot of resistance when pulling the rope.

What should I learn from this? Should I pull the head to see what things look like and install a new head gasket to see if that helps?

Thanks[/QUOTE

50 is low your comp gauge is now toast ..a little bit of oil in the cyl will boost the comp for sure place your thumb over the hole and have someone pull it over if it moves your finger off the hole its good if not pull the head and have a look and see what the cyl looks like if its scored up bad the motor is junk if the cyl looks fine replace head gasket also check to see if the valves are closing proper

 

[ricklea1953]

Thanks for the replies. My next step will be to pull the head, after I find the correct gasket.

 

[briggs]

Thanks for the replies. My next step will be to pull the head, after I find the correct gasket.

i would pull the head of first before u spend any money on it to see whats up in there ...