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Hi guys and gals, a client of mine just bought an Ariens tractor with a 2015 Briggs, MOD: 33R877 0009 G1, CODE: 150109ZD. He called and told me that the starter was overheating and wouldn't crank the engine over. I took a look at it and found that the engine was locking up on the compression stroke and figured it just needed a valve lash adjustment. I told him to get on the phone and let the warranty work, but whoever he spoke with told him that the valve lash service wasn't covered under warranty. So I decided to take a look. The service manual tells you to:

1. Turn crankshaft counterclockwise until piston is at top dead center on the compression stroke. This prevents the compression release from holding the valves open.
2. Insert a narrow screwdriver or rod into the spark plug hole as a gauge, then slowly turn crankshaft counterclockwise until the piston has moved down the bore by 1/4
3. Using a feeler gauge, adjust rocker nut to obtain the clearance as listed (.003 - .005 in. for both intake and exhaust)
4. Hold rocker nut and tighten the rocker ball setscrew to the torque valve shown in Section 12 - Engine Specifications.
5. Check clearance again and re-adjust, if necessary.
6. Repeat for other valve.

I did this, put the spark plug back in, turned the engine over by hand and it is still locking up on the compression stroke. So then I turned to all of the old tricks up my sleeve and nothing has worked so far. Another tech told me that the compression release spring on these engines have a tendency to break or come off. What do you guys know about this? Any other suggestions? I know some of you will probably say, "It's under warranty, just take it in to an authorized dealer for repair", and I agree with that. But I would like to know more about this issue and gather as much information for my personal use as possible. And yes, I called Briggs. They told me, ..."just take it in to an authorized dealer for repair". No help. Thank you in advance!

If you are sure the valves are adjusted correctly, then it sounds like the compression release has failed on the camshaft. I will adjust the valves, and then turn the engine over a few revolutions and watch for the valve compression bump off. If not present, then suspect camshaft issue. Most that I see don't fail during the warranty, they normally wait until the warranty has expired before failing. I find more with broken compression release weights laying in the oil pan, then just compression release spring problems.

If everything checks out and suspect compression release failure, it will need to go a authorized briggs service center for warranty.

Thanks for confirming my suspicions @ ILENGINE! Really appreciate this forum and you guys sharing your experience. Just to share a little more, I found this helpful information on another forum:

"To check the compression release mechanism:

- 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."

msmallenginerepair said:

Thanks for confirming my suspicions @ ILENGINE! Really appreciate this forum and you guys sharing your experience. Just to share a little more, I found this helpful information on another forum:

"To check the compression release mechanism:

- 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."

Click to expand...

I am the author of the quote you posted on compression release test.

I don't know where you got your instructions on adjusting valves, it was not from Briggs & Stratton Service Manual for single cylinder OHV engines which says, "Adjusting valve clearance - all" "Turn crankshaft clockwise (flywheel end) ------ past TDC until piston is 1/4" down."

First thing you need to do is adjust the valves CORRECTLY before tearing down looking for a CR release problem.

IF you still do not under stand the proper process, I can send you detailed instructions, address below, put in proper format and remind me engine model number and what you want.


Walt Conner
wconner5 at frontier dot com

Tinkerer200 said:

I am the author of the quote you posted on compression release test.

I don't know where you got your instructions on adjusting valves, it was not from Briggs & Stratton Service Manual for single cylinder OHV engines which says, "Adjusting valve clearance - all" "Turn crankshaft clockwise (flywheel end) ------ past TDC until piston is 1/4" down."

First thing you need to do is adjust the valves CORRECTLY before tearing down looking for a CR release problem.

IF you still do not under stand the proper process, I can send you detailed instructions, address below, put in proper format and remind me engine model number and what you want.


Walt Conner
wconner5 at frontier dot com

Click to expand...

Hi Walt, I got my instructions directly from the Briggs & Stratton Service Manual for Single Cylinder OHV Air-Cooled Engines. It covers the following series:

MODEL 110000 HORIZONTAL SERIES
MODEL 120000 HORIZONTAL SERIES
MODEL 150000 HORIZONTAL SERIES
MODEL 200000 HORIZONTAL SERIES
MODEL 210000 HORIZONTAL SERIES
MODELS 97700 & 99700 VERTICAL SERIES
MODEL 110000 VERTICAL SERIES
MODEL 120000 VERTICAL SERIES
MODEL 210000 VERTICAL SERIES
MODEL 280000 VERTICAL SERIES
MODEL 310000 VERTICAL SERIES
MODEL 330000 VERTICAL SERIES

The engine I am working on is the MODEL 330000 VERTICAL SERIES. The instructions for this model are different from the normal procedure, which you describe in your reply. And by the way, I graduated at the top of my Small Engine Technician class

My quotes I sent came word for word from B&S Service Manual for Single Cylinder OHV engines, section 6, page 13. The 33 series engine is NO different than 31 and is just a bored out 31. The named manual says, "Including 33 series".

Regardless, IF you are doing as you posted, you are dong it incorrectly. IF you are doing custom work, repair work for money, you should know better. My offer of Detailed Instructions stands.

Walt Conner

Tinkerer200 said:

My quotes I sent came word for word from B&S Service Manual for Single Cylinder OHV engines, section 6, page 13.

Regardless, IF you are doing as you posted, you are dong it incorrectly. IF you are doing custom work, repair work for money, you should know better. My offer of Detailed Instructions stands.

Walt Conner

Click to expand...

Right back at you buddy. My instructions are quoted word for word from the correct manual. I have been doing this for years, on numerous engines. For your information, I also tried doing it the traditional way that you are quoting after the other instructions failed, and that did not work either. It is obviously a broken compression release mechanism and will require engine tear down. Sounds like you might need some updated information Walt. Would you like me to send you the Briggs Service Manual for this engine series? I have it in PDF format. If so, just send me your email and I will get it off to you.

You are correct, Intek singles are adjusted differently than twins and Vanguard twins.

Here is a fool proof way. Works on every engine.
Turn the engine counterclockwise by hand till one valve is open and the other is closed. Adjust the closed valve.

If you do the 1/4 past tdc then you have to Measure the stroke then go 1/4 of it down.

You both are arguing over a simple procedure.

It's a small engine there is nothing complicated about it.

Thanks Mad Mackie and Carscw for that clarification! Carscw, I agree with you 100% and I also tried the method you describe, after I did it by the book. That also failed which left me feeling pretty sure the the compression release mechanism had failed. Thanks again everyone!

Carscw said:

Here is a fool proof way. Works on every engine.
Turn the engine counterclockwise by hand till one valve is open and the other is closed. Adjust the closed valve.

If you do the 1/4 past tdc then you have to Measure the stroke then go 1/4 of it down.

You both are arguing over a simple procedure.

It's a small engine there is nothing complicated about it.

Click to expand...

You're right, it isn't complicated. But that is not the right way to adjust valves. Doing it that way, the lifter (or valve stem, on flatheads) will be approximately perpendicular (90 degrees) to centerline of the cam lobe. 180 degrees is the ideal spot, where the lifter is on the base circle and directly opposite the cam lobe.

cpurvis said:

You're right, it isn't complicated. But that is not the right way to adjust valves. Doing it that way, the lifter (or valve stem, on flatheads) will be approximately perpendicular (90 degrees) to centerline of the cam lobe. 180 degrees is the ideal spot, where the lifter is on the base circle and directly opposite the cam lobe.

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Well dang.
1000s of us have been doing it wrong for 50 years.

It has been tested over and over to be the best way.

Adjust your valves with one of the ways in this thread. Then check them using the other 2 ways. I bet the valves will read the same. If done right.

Do you really think that most people take the time to know where a 1/4 from tdc is?

Carscw said:

Well dang.
1000s of us have been doing it wrong for 50 years.

It has been tested over and over to be the best way.

Adjust your valves with one of the ways in this thread. Then check them using the other 2 ways. I bet the valves will read the same. If done right.

Do you really think that most people take the time to know where a 1/4 from tdc is?

Click to expand...

You don't have to.

Set the intake when the exhaust just starts to open.

Set the exhaust when the intake has just finished closing.

It's that simple. It puts you as close as you can get to that ideal spot that I described.

That is the way I was taught to do it.
it is also the recommended way to do all BSA pre-WWII motorcycles as they had substantial opening and closing ramps to make the engines quieter.
Also no matter what the valve timing is or the addition of decompression devices, you can not go wrong if you use the opposing valve method.