Too much compression?

[mechanic mark]

Crap. That does sound exactly like what its doing.

Don't assume anything or get down, read my post above & watch video.

https://www.google.com/search?q=4+STROKE+ENGINE%2F+INTAKE%2C+COMPRESSION%2C+POWER%2C+EXHAUST&oq=4+STROKE+ENGINE%2F+INTAKE%2C+COMPRESSION%2C+POWER%2C+EXHAUST&aqs=chrome..69i57j33i22i29i30.51656j0j4&sourceid=chrome&ie=UTF-8

Read above by clicking on website. Are you sure you were on correct stroke when adjusting valves? You may have been 180 degrees off. With spark plug out, engine cold of course, insert dowel, pencil, screwdriver, etc. making sure piston is at TDC, top of stroke, then go 1/4" past, both rocker arms should be loose & even with valves closed. You are now ready to adjust both intake & exhaust valves to specs.

 

[familyman121712]

Don't assume anything or get down, read my post above & watch video.

Yep, did that last night. Matter of fact thats the same video I found.

 

[familyman121712]

Yep, did that last night. Matter of fact thats the same video I found.

Sorry, hit the button before I finished. When I checked the lash before I reset it, they were at .005 intake and .008 exhaust. I set them to .004 and .006 like you suggested.seemed like a good spot right in the middle of tolerance. Didnt change anything, though.

 

[Scrubcadet10]

Parts tree shows the cam as in stock (leaves within 1 business day)

PartsTree - Home of OEM Parts for Outdoor Power Equipment

Parts lookup and repair parts diagrams for outdoor equipment like Toro mowers, Cub Cadet tractors, Husqvarna chainsaws, Echo trimmers, Briggs engines, etc.

www.partstree.com

Appears available at jacks.

https://www.jackssmallengines.com/jacks-parts-lookup/part/briggs-stratton/84005207

also plenty of Chinese aftermarkets on amazon. https://www.amazon.com/s?k=84005207&i=automotive&ref=nb_sb_noss_1
although star tech has mentioned issues with the cam journals being slightly over sized.

 

[StarTech]

Either way telcon either vendor to be sure they have it in stock. Jacks is bad at having to order items after you order it.

 

[ILENGINE]

IL, I think I see why the ACRs are failing and it is a design problem. Even when the ACR is fully retracted the pin is still loose enough to be constantly bump by the tappet rocking the pin until it breaks off sending the ACR weight flying across the engine. It is just like you bending a piece until it breaks. And sometimes it takes out the governor while at it along other damage. The last two I did use aftermarket camshafts ACR had damage the governor too. THe next to last one actually snag the cylinder a little, lucky it was just a nick.

It is a sloppy design and I would agree that is the reason they are a high failure item.

 

[njswede]

I have a poulan pro riding mower with a briggs and Stratton 19hp ohv engine. The battery us fully charged, the starter is brand new, I've checked the valve lash and made sure they are moving. Compression still stops the crank. Any ideas?

I was driving myself nuts trying to track down this issue. Tried new battery, valve clearance, starter solenoid and everything else. It ended up being a leaky needle valve seat in the carb. It caused the engine to aqua lock when it sat for a while. Take the plugs out. If gas comes pouring out then you have this problem. You then have two options: Rebuild/replace the carb or install a fuel valve you keep closed when you’re not using the mower.

 

[njswede]

…also, if that turns out to be the problem, I highly recommend an oil change! More likely than not, you trying to crank it has pushed some gas past the piston rings and into the oil.

 

[SamB]

I had this cam/ACR issue a while back. A "hack" I learned was if you just have to get the Briggs running to mow,covering the intake at the carb will not allow air into the engine and the engine will turn over fast enough to start as soon as you remove your carb covering. I used a piece of rubber I cut from an old floor mat. Hey,I did say it was a hack,but it does work. LOL!

 

[Ronni]

I have a poulan pro riding mower with a briggs and Stratton 19hp ohv engine. The battery us fully charged, the starter is brand new, I've checked the valve lash and made sure they are moving. Compression still stops the crank. Any ideas?

I had the same problem with a new mower I had just bought. It turned out that gasoline was flooding through the carburetor and filled the piston with gasoline during the compression stroke. This totally locked up the engine from starting. It would not crank at all. I took it back to Lowes and got another mower in exchange.