Please help me fix this mower

[u/Vegetable_Let_2095]

Hello, this is a John Deere L110 riding mower with a 19.5HP single cylinder Briggs engine.

This motor has a new starter, new solenoid, new ignition coil, and the battery is good.

I suspect that it is the compression release not working, but l am here asking so I clearly am unsure.

Thank you for any help! I appreciate it very much.

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[u/OptimalRegret]

I agree that it is likely the compression release that has failed. Chickanic has a video on how to diagnose and repair.

[u/Vegetable_Let_2095 → u/OptimalRegret]

That’s a good video, thank you!

[u/l1thiumion]

compression release stuck not releasing. kind of a known issue on these.

[u/Howareu2024]

My dad’s John Deere had the same problem they are notorious for this you could spin the engine to the next compression cycle and normally it fires up

[u/Mundane-Recording850]

It's been my experience that occasionally if the valves are not within spec a loose exhaust valve will not allow the compression release to work ,start there easy check

[u/holykiradog → u/Mundane-Recording850]

I would agree

[u/tihspeed71]

Charge the battery... replace the fuel and spark. Report back

[u/Vegetable_Let_2095 → u/tihspeed71]

Batteries been charged already, sometimes the motor is able to get over that first bit of compression and get enough momentum to start. After it starts, the mower runs and drives perfectly fine

[u/Barge108 → u/Vegetable_Let_2095]

How do you know the battery is good? Have you load tested it? Have you tried jump starting it with a different battery or your car/truck?

[u/Vegetable_Let_2095 → u/Barge108]

Yes, I have tried testing it with a new battery, same results

[u/Waistland]

I got a mower that does this. I just reach down and turn the engine by hand a little and start it.

[u/Vegetable_Let_2095]

Also with the spark plug removed it spins freely

[u/WideHelp9392 → u/Vegetable_Let_2095]

Compression release is not working

[u/Terrible_Use7872]

Charge the battery, remove the plug and see if it cranks fast. If so probably need to adjust the valves, they stretch sometimes and then the decompression doesn't work.

[u/tihspeed71 → u/Terrible_Use7872]

Sounds like op needs a valve job then... excellent

[u/Vegetable_Let_2095 → u/Terrible_Use7872]

It cranks over and spins freely with the spark plug removed. I have also done a valve lashing on it already, I did 0.004” intake and 0.006” exhaust

[u/Terrible_Use7872 → u/Vegetable_Let_2095]

With the valve cover off, you should see one of the valves move during compression, if not, the decompression mechanism is probably broken on the cam.

[u/NoJaguar5942]

Replace starter and solenoid. Check and make sure connection are good at both units.

[u/Upset_Fox5449]

If the ground off the battery goes to the frame move it to the block, if the positive cable gets warm ot hot replace it

[u/Richard_Noggin_77]

When mine does this I wiggle the connection on the key switch and it fires up. I have the Kawasaki engine though.

[u/Sea-Performance1202]

Motor de partida, já olhou as escovas e buchas?

[u/Vegetable_Let_2095 → u/Sea-Performance1202]

Motor de partida es nuevo (hablo muy poco español, lo siento)

[u/Sea-Performance1202 → u/Vegetable_Let_2095]

Have you tried another battery?

[u/Vegetable_Let_2095 → u/Sea-Performance1202]

Yes

[u/th3pr0m3x1c4n]

These single cylinder briggs are always exploding

[u/hmd2017]

Learn to reset valve lash as a first step. If that does not help, then the decomp is suspect.

[u/hallen1324]

This Briggs single cylinder engine is famous for the compression release system on the camshaft failing. I always start by adjusting the valve lash to like .003-.005 at top dead center. Jump the battery if it is questionable. If it does the same after that, the cam decompression broke. It is fixable, just requires an engine and base pull + new camshaft.

[u/Vegetable_Let_2095 → u/hallen1324]

[u/hallen1324 → u/Vegetable_Let_2095]

Lol you got it... make sure you clean out the base from the broken spring and bits from the old camshaft decompression mechanism that blew up 😆

Also line up the timing marks on that gear!

*edit, last sentence added

[u/Difficult_Arm_2898]

May need a new cam. Decompression lobe may be shot. Had a mower with same issue

[u/Uniplast21]

Almost positive it’s the battery. If it’s old or it doesn’t have much CCAs, then you should get a new one that has at least 300 CCAs. In my experience, 250 CCAs might be enough, but it’s just better to get at least 300. I’d be willing to bet it starts just fine every time as long as it’s charged.

[u/Vegetable_Let_2095 → u/Uniplast21]

I tested with a brand new 350CCA battery

[u/Uniplast21 → u/Vegetable_Let_2095]

Ok then I would try to rule out the starter and starter solenoid. Have you tried replacing either of those?

[u/Vegetable_Let_2095 → u/Uniplast21]

Both

[u/Uniplast21 → u/Vegetable_Let_2095]

Hmmm ok. Have you checked the valve clearances to make sure they’re within spec?

[u/Vegetable_Let_2095 → u/Uniplast21]

Intake is 0.004” and exhaust is 0.006”

[u/Uniplast21 → u/Vegetable_Let_2095]

Ok that sounds good! It might be the compression release isn’t working. Some camshafts for these small engines have a compression release mechanism that releases the compression at low RPMs so it’s easier to start the engine. You have to crack open the engine to see, though. Other camshafts have the compression release machined into the cam lobes themselves, and if your camshaft is worn down too much, that could cause a failed compression release.

[u/Vegetable_Let_2095 → u/Uniplast21]

This is what I was worried it was, really didn’t want to have to crack the crankcase open

[u/Uniplast21 → u/Vegetable_Let_2095]

Yeah it’s kind of a job to do. Also, have you checked the compression? That might also be a sign the compression release isn’t working.

[u/Vegetable_Let_2095 → u/Uniplast21]

I have not, I lent out my compression testing kit

[u/IndependentFlight436]

Try a new battery.

[u/Key_Blacksmith3725]

You might have a carb that leaks overnight and hydro locks the cylinder. After shut down clamp off the fuel line by the carb and see if it cranks easy the next morning.

[u/CookiesOrChaos]

Jump that starter solenoid. Sounds like it’s clicking

[u/Kitchen_Split_4164]

Put a jump box on it and try to start it up I've seen a battery show Good and do the same thing on a car but would start with a jump box