Start Compression Locked Briggs & Stratton Engine

How to start a compression locked Briggs & Stratton Engine. B&S engines in a certain series (330000 & others) have a known mechanical failure with the compression relief mechanism. This video shows a work around to starting an engine with this failure.
*Please use your own discretion when starting an engine with a compression relief failure. It's common to find metal pieces of the mechanism within the engine when it fails. This can harm your rotating assembly.

[nevilledoll]

Just a note fellas, i had this problem, fitted a cam kit, had same problem, checked and set valves problem fixed, Cam decompression does fail, but i got caught by loose valves. Cheers and good vid.

[KBuckyRailVideo]

Thanks for the video. My Intek 20hp B&S did this a few years ago and I paid someone around $300 to repair it. All was well until a few days ago when it behaved like the battery was not charged enough to start. I tried a new battery with no change. I then replaced the starter solenoid with no change. My next step would've been the starter, but as much as I was in denial, the compression issue was the cause. I turned the wheel on top of the engine backwards about two turns and it started. Got about 3/4 of my lawn mowed and figured since I can at least now start it, I'll finish the next day, Nothing doin'. after 15 tries I headed to my local hardware store and purchased a new mower with a Kawasaki engine. In my world Briggs & Stratton can never be trusted again.

[dereknewton]

Working on a Craftsman that's been sitting for 8 years, was having the same problem. Did exactly what you did and replaced the plug and it fired right up. You're a lifesaver! Thanks for the video!!!

[kennethrutledge]

Dude!!! Thank You so much for the tip on starting without a new cam !!! I just put a new cam in this thing 4 months ago and it did it again !! First thing is the morning I’ll git er dun!! !!! Thanks again!!!

[kenw.]

NICE VIDEO ! HAVING THIS ISSUE WITH A CRAFTSMAN LT1000, 15.5 HP ENGINE 42 " CUT. MY THOUGHTS WAS TIMING IS OUT OF WACK. DID NOT KNOW ABOUT COMPRESSION RELIEF VALVE. WILL TRY THIS! BEST INFORMATION I HAVE FOUND IS YOURS . THANK YOU !!!!😊😊😊😊😊😊

[jeffrandolf]

I've been doing, something similar to this for 2 years. I never knew there was a decompression mechanism at all... so I assumed battery &/or starter were NO GOOD. I replaced them both with NO LUCK. I was able to spin the flywheel by HAND (top of motor) to get it past the compression stroke WITHOUT removing spark plug.
FYI... I hooked a battery BOOSTER PACK directly to starter (+) post while simultaneously turning key to "Start" postiion & was able to get it to crank enough to start WITHOUT getting to TDC nor using starter fluid. Prolly gonna burn up my NEW starter, though.
*EDIT:* After reading all the comments below... gonna check valve adjustment FIRST. 2005 B&S 17.5hp.

[eroksizzle]

This seemed to be the trick that worked. Thank you so much. Apparently, my gas is old but adding fuel stabilizer and following your steps from this video worked perfectly. 💪
Thank you

[MrCountrycuz]

I adjusted the valves on my YT3000 and it has ran for the last two years like a champion!
The compression release depends upon proper valve adjustment. I run ethanol free fuel that I process my self and I also had a squirt of two stroke to the fuel to give it some top cylinder lubrication.
I run a YT3000 with a 21 hp platininum.

[geoffwalker]

Thanks for this very useful video.
I checked the valve clearances but knew from the symptoms that the decompression mechanism was broken on my Intek version.
I wound engine ccw until resitance was felt and found that 12.5 volts wasnt enough, so gave it 14.4 volts off a running car and that started it.

[raymondsadowski]

You can also turn the engine backwards to that same spot like you were doing with the fly wheel cover without removing the spark plug.

[michaelglenn]

I done everything I could to get my 18 horse brings to turn over I could...now I know why it's the compression relesee unit that's failed and I discovered the back up compression trick to get it running on my own... need to take a picture of the mod and tool I made to get it going really easy.

[christmasduck]

Had this problem on a Biggs & Statton engine as soon as I removed the spark plug petrol came flowing out of the engine, that was causing the compression problem .Previously I had been working on problems getting the carburetor float bowl to seal eventually sorted that problem, I'm not a Mechanic so no idea how the engine flooded but fires up perfect now. Thanks for your video.

[JasonTylerRicci]

I'm convinced my compression relief mechanism has failed, since I have a newer battery and starter. The only reason I'm dreading the repair is that it's my only mower so I'd need to repair it in a timely manner. I'd be OK running it with these "hacks" but worry about a major failure if the mechanism is sitting somewhere at the bottom of the sump cover. Thank you for sharing!

[upsidedowndog]

A 500 CCA battery for a touring Harley has kept mine working for around 3 years (and it was 3 years old when I got it for free).

[palorodriguez]

Thank one more time. Very clear to speak. Amen.

[brokenglasses]

I've been starting a v twin for 5 years since I bought it used by rotating the engine to top dead centre on the stiffest cylinder, then just past it. From there the starter cranks its fine. I always thought it was the sealed battery had been incorrectly charged and compromised by the previous owner (lots of warnings in the manual supplement), but I was surprised that a brand new battery didn't change anything. So I've now just discovered this compression release mechanism fault. It seems though that even a slightly too wide gap on the exhaust valve tappet can cause it, as the compression release 'bump' is so slight a oversize gap will mean the exhaust valve just doesn't open that little fraction to decompress. So next job is set the tappets.

[choppergirl]

I saw a video where if you take your hand and put it over the air intake, that will prevent air from getting in and compression building up, and allow your engine to turn over, and once it is running or gets going you can release your hand and let air in. I haven't tried it yet.

[robertbartlettii]

So, I've not tried this yet, I was actually in the middle of removing the engine, 17.5 hp 500cc b&s on a troy bilt pony. Was looking up videos on removing/repairing it when I ran across your video. Now considering putting the carb and everything else back on and try this temporary band aid.

Question tho.... the last time I ran it, it suddenly revved up then began surging. I finished the lawn then ordered new carburetor, plug, filters, and got some sea-foam for the fuel. Replaced all that, went to start it, and wham! Wouldn't turn over. Pulled the plug and it spun no problem, also there wasn't any fuel coming out when I removed it, so I don't think it's an issue with fuel and must be compression, but that's just a guess because I really don't know much about these engines.

My question is, given the symptoms I mentioned prior to parking it to repair, and the engine locking up, also when I turn it with plug out when it reaches compression it sounds like a horn softly honking coming from the breather tube, is that normal?
Anyway, given all that, anyone have an idea what it could be? The root cause, problem.

Thank you, anyone, for any insight

[Copycatcarnivore]

So if anybody is still watching this particular video, simply turn your engine backwards until you feel the compression, then take the air cleaner off, put your hand over the carburetor and turn it over. It will fire up immediately, then put the air cleaner back on and away you go once it's warm it will fire up from after you turn it off for a few minutes.

[fastguned]

My 1996 Tractor style Snapper with Briggs engine was doing the same thing. I adjusted the vales. No help I could turn the engine by hand w/o removing the spark plug and no starting fluid. I turned it past the compression stroke and started it. My battery checked out good but it was a 4 year old Die Hard from your local members store. I put a new Wal mart battery in it with 25 less amps and it is starting now even better than that Die Hard did when new.