Won't Spin Past Compression Stroke

[Tiger Small Engine]

After 18 replies, 3 different starter replacement attempts and jumping with a vehicle battery, the obvious that has been explained is not sinking in.

This seems to be stuck in a "let's replace something loop"... valve adjustment does not compute. No capability?

Some people have trouble listening and learning. Some people think their skills exceed reality. Most people, gratefully, are not like this.

 

[David40]

Have the same issue with one of my mowers. It's the failed compression relief device. A major pain to fix requiring removal of the engine. My work around is to manually rotate the engine to just past TDC and then start it. Once the piston is at or slightly past top dead center it has enough of a head start to keep spinning and starting. It's a bit of an inconvenience but a lot easier than tearing down the engine to replace the part. Also, this will not work if you have a weak battery so make sure that's strong. Oh and another thing. When the compression device fails all the metal pieces will have fallen to the bottom of the crank case. I took one of those earth magnets on a flexible shaft and removed all the metal pieces through the oil fill tube.

 

[Albuck]

Will almost guarantee its yiur compression release spring. Simply cover the intake on the air box assembly with a piece of cardboard and try it. Once it fires up remove the cardboard and it will run fine as the spring only comes into play to start it. Shame it requires a teardown to fix a two dollar part.

 

[mpqualdie]

Model 33R777
Type 0003 G1
Code 190214ZD
Single cylinder.

Will not spin past compression stroke.
Battery measures 12.8 v. Starter is new (and all this was tried with 2 used starters as well, so 3 different starters).
Battery connections cleaned, starter relay connections cleaned.
Battery voltage measures 12.7 all the way to the starter; battery, starter relay input, starter relay output, starter lug.
Remover spark plug, spins like crazy.
Attached car battery. Will not spin past compression stroke. Remove spark plug. Spins like crazy.
Attach compression gauge, struggles with partial spins, but got 100 psi , so it may register more if the engine could spin enough to give a good test.
So, why, if all parameters measure good, will the starter not get past compression?
Thank you,'
J

The compression release on your cam is broken, or your valves need adjusted. There's a little nub that cracks open the intake valve just a hair to relieve the compression. Once the motor starts centrifugal force will pull the nub in and it runs normal. Very common problem on the B&S motors.

 

[glyn1718]

The compression release failure appears to be the favoured diagnosis provided that the engine is on the mower with the blade fitted when you were turning it over. The blades and belts driving blades act as a flywheel that enables the crank to pass through compression stroke. (As anyone who had tried to pull an engine over with no blade connected and experienced the kick back will tell you!).

 

[jamesds016]

Model 33R777
Type 0003 G1
Code 190214ZD
Single cylinder.

Will not spin past compression stroke.
Battery measures 12.8 v. Starter is new (and all this was tried with 2 used starters as well, so 3 different starters).
Battery connections cleaned, starter relay connections cleaned.
Battery voltage measures 12.7 all the way to the starter; battery, starter relay input, starter relay output, starter lug.
Remover spark plug, spins like crazy.
Attached car battery. Will not spin past compression stroke. Remove spark plug. Spins like crazy.
Attach compression gauge, struggles with partial spins, but got 100 psi , so it may register more if the engine could spin enough to give a good test.
So, why, if all parameters measure good, will the starter not get past compression?
Thank you,'
J

Check the compression release, those were notorious for the spring breaking.

 

[Scooba]

Model 33R777
Type 0003 G1
Code 190214ZD
Single cylinder.

Will not spin past compression stroke.
Battery measures 12.8 v. Starter is new (and all this was tried with 2 used starters as well, so 3 different starters).
Battery connections cleaned, starter relay connections cleaned.
Battery voltage measures 12.7 all the way to the starter; battery, starter relay input, starter relay output, starter lug.
Remover spark plug, spins like crazy.
Attached car battery. Will not spin past compression stroke. Remove spark plug. Spins like crazy.
Attach compression gauge, struggles with partial spins, but got 100 psi , so it may register more if the engine could spin enough to give a good test.
So, why, if all parameters measure good, will the starter not get past compression?
Thank you,'
J

Open the crankcase cover and replace camshaft. There is a decompressor on your camshaft that slightly opens the exhaust valve during cranking. It does that to release compression s it won't be difficult to turn. Same thing as on pull start engines.
That decompressor turn to break on those Briggs engines.

 

[outdoorpowermike]

If valves are adjusted right at .004 and stops cranking the compression release built onto camshaft is broken. Needs to be replaced along with case gasket and lower seal. It only takes about 2 hours to do if lower pulley slides off.

 

[kjonxx]

Model 33R777
Type 0003 G1
Code 190214ZD
Single cylinder.

Will not spin past compression stroke.
Battery measures 12.8 v. Starter is new (and all this was tried with 2 used starters as well, so 3 different starters).
Battery connections cleaned, starter relay connections cleaned.
Battery voltage measures 12.7 all the way to the starter; battery, starter relay input, starter relay output, starter lug.
Remover spark plug, spins like crazy.
Attached car battery. Will not spin past compression stroke. Remove spark plug. Spins like crazy.
Attach compression gauge, struggles with partial spins, but got 100 psi , so it may register more if the engine could spin enough to give a good test.
So, why, if all parameters measure good, will the starter not get past compression?
Thank you,'
J

Adjust the valves if no help then compression release not working.

 

[RestoGuy]

Easiest diagnosis of the year...broken compression release on the cam...don't waste your time chasing other causes. Briggs and Scrappem engines are famous for this failure. I have replaced the cam on my BS before I sold the mower and fixed two other engines for friends. Not a complicated repair, just time consuming as the engine must be removed and taken apart. Moral of the story...avoid single cylinder Briggs and Scrappem engines.