How To Clean A Briggs And Stratton Carb Youtube

Hi Guys,
I see this thread is quite old now, but I came across a solution with the help of a buddy whose a small engine mechanic. I teach small engines at a high school, and had the "too much compression" issue in some of our 5.5hp OHV briggs engines that the students tear down, measure and reassemble. I've attached a couple photos from the textbook I remembered I had once the local small engine guy tipped me off about the compression release.

Many Briggs and Strattons have a compression release system that relieves excess pressure during the compression stroke by releasing a small amount of compressed gas through either the intake valve or the exhaust.

There are two main ways that they accomplish this. The first is through what they call an "Easy Spin" compression release system. They use a second raised side on the cam lobe to raise the valve slightly off of the seat immedietly prior to maxumum compression pressure. Briggs admits that they'll have to do away with this in time due to stricter and stricter emmissions testing.

The second way, and more common way, is to use a mechanical release. The ones we have at school opperate simply by a weighted arm and a small spring. The issue we had with too much compression was due to the little spring coming unhooked. My small engine mechanic friend said he repaired one where there was actual pieces broke off, and picked up on it because there was a bit of damage to the cam from broken pieces that the customer claimed were never there in the first place. (The customer must have opened the crankcase, chucked the compression release mechanism, and claimed it never happened.)

If you're sure your timing is correct, as in you haven't had your camshaft out recently, or you're sure it's timed correctly, then follow the following procedure:

1. set valves correctly (make sure the piston is 1/4" down from TDC on power stroke, the reason it needs to be down 1/4" is to ensure that the compression release isn't interfering with your valve lifter).

2. check compression release

- Remove the spark plug
- Remove the valve cover, turn the engine flywheel clockwise while watching the valve action.
- When the Intake Valve closes, stop.
- Now focus very closely on the valve spring retainer of the Intake Valve, continue turning the flywheel clockwise. In about 1/4 turn, you should see the Intake Valve Retainer (and valve) make another little move towards fully closed.
- This indicates the Compression Release is working.
- IF you see no movement, try again.
- Still no movement, there is a problem in the Compression Release system. When the engine is cold, you can rest the side of your hand on the head and grasp the Intake Valve Spring Retainer between you thumb and index finger while turning as described and you should be able to feel the Retainer move.

I've done a bit of searching around on the internet and couldn't find this solution. Hopefully it solves everyone's problems, and that your engine is sitting in the corner of your shop or garage somewhere, and hasn't been sold for scrap metal! Again, ours was as easy to fix as reattaching a small spring that had become unhooked.