Briggs and Stratton 19.5hp opposed twin engine not starting (42E707) - Craftsman riding lawn mower 

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Not sure if you've gotten running or not... Make sure coil is set correct distance from flywheel, .010-.012" or a business card thicknesses. Also sand clean the magnets on the flywheel for good contact with 1000-1500 grit sandpaper. Your flywheel should be spinning faster, fully charge battery, plug gap .030, NGK BR2LM plugs, non-ethanol gas & Sta-bil will keep gas fresh & carb from gumming up during storage. Other suggestions ppl made are spot on too. If still no start, remove plugs to ensure compression, if no compression then look @ valves, pull flywheel & check key, several videos on here how to pop that off. Provide update if you can Briggs Opposed Twins are great long lasting engines as long as you change oil & maintain carb.

i had exactly the same problem. changed the starter and proplem solved!

Have you tried a direct jump to the starter to see if it cranks the same? Black jaw on a bolt to ground and touch the red jaw to the positive on the starter.

I am having the same problem with my 42E707 19.5 HP . If I can get it to start, it runs fine but I have the same compression issue that isn't allowing the engine to turn over. I noticed on other videos that some engines have a compression release valve that is attached to the camshaft. It causes the valve to be partially open only during starting, which reduces compression. This part can fall off the camshaft and then you will have a compression issue preventing the engine from turning over. Also there would be metal parts in the oil base that could cause huge damage if the moving parts were to come into contact. I am not 100% sure this engine has this compression release valve as it isn't clear on the parts diagrams. I suppose the first step would be to check the current valve lash to see it it is near specification. My opinion is if the valves were worn there would be less compression and not more as the valve stem would be closer to the push rod and hold the valve open.

hi this is Gil I was watching your video one more time when I saw you put your hand on the flywheel and spent it, I noticed that the shaft in the middle did not spend with it, might want to check your key on the flywheel if it's broken, if key is broken timing will be off and it won't start.

For Pete sake people, the valves are non adjustable on an opposed cylinder flat head! You must remove the head and lap new valves and seats

You need to adjust the valves that's exactly what the problem is. I had the same issue with a 20 horse Briggs & Stratton Vanguard adjusted the valves and it turned beautiful

It’s been over a year, any progress on diagnosis and what you did to remedy? Comment section was pretty helpful.

Check out " post 10" on RU-vid to check valve clearance on flathead engine. It's the little silver cover on the front of the twin opposed. More than likely its the exhaust valve that needs fixed.

Thanks for posting this video. I just got the same right lawnmower for free wondering what year it is you know any other info you could tell me when I got mine I just brought it over on a ferry and I’m in Washington state and my cousin threw a car battery on it and dump some gas in the in the in the carburetor where the oil filter is, he just dumped a little bit of gas in there. I think fired up and I got it at my place now I’ve got issues with mine. It doesn’t have a belt for the deck and the battery that my cousin gave me is too small but also it needs a tire so I’m gonna go tube. I’m gonna go buy a tube today and see if I can’t get it driving around. At least you know God bless.

Hey Did you ever resolve starting issue ? Possibly weak / bad starter or ground issues or too small ted starter wire coming from battery ?

You might have to adjust your values, when there out of adjustment it can turn hard.

It’s struggle on the compression stroke u new a better starter cuz them motors have a high compression take one spark plug out and turn it over and u will see

Put so e jumper cables on battery, not enough juice to turn fast enough

I had the same problem. As a solution, I installed a larger 100A relay and a smaller car battery. :) The original battery can't crank the engine. How can the valve clearance go out of adjustment? Today in 2024, I used AI and it offered quite a few solutions to check.

Not spinning fast enough - bad starter? bad battery? Loose connection between battery and starter? (people look at the Positive cabling , but forget the Ground connection.).

Make sure your coil is not to close to your flywheel

adjust the valves. The cam has the governor on top of it. behind the cam sprocket there is a centrifugal force device to operate moving balls in the first two lobes that relieve compression at start up. IF the valves are out of adjustment the balls wont do its work.

I've seen videos talk about the compression release locking it from spinning... Look those up. I think you have a compression release issue.

Compression release not working. Replace cam shaft

Put a new battery in it and make sure that it's the most cca I put in my 500 cca battery and it has no problem turning over

The ROP Shop Compatible Ignition Coil Replacement for Briggs & Stratton 392329, 394891, 394988, 590781

Load test your battery and check all connections. If not a starter issue, I found my solenoid to be bad. The contacts internally were so bad that it couldn’t provide the amperage needed. From what I see? It’s not a coil issue. The opposed Briggs are awesome engines.

i think you need a new starter or better battery and your air gap is set too close on the coil

Didn't have to watch too much of the video - one problem for sure is that it is barely turning over.

Did you ever figure it out?

Using the wrong coil I had this problem before

Fly wheel keyway needs to be replaced

I replaced the battery and solenoid on mine and still get nothing when I turn the key, I don't know if it's the starter, not sure why it's not firing. At least you are getting it to turn over. Did you find the problem?

How would you even adjust the valve lashing on this unit

Did you figure out what was wrong? I have the same issue with you!

That's how mine was turning over before I replaced the starter. It did that for two years then the teeth were gone. And replacing the starter solve the issue. ru-vid.com/show-UC2q-idTXK7MmaJVk_r173Ug I think what's happening is that the chewed up gear is adding mechanical resistance, and the old wiring electrical resistance, making the starter too week to get past the firing point of one cylinder. BTW, you haven't tightened or replaced any of your belts lately have you? Because dragging belts can also slow down your starter.

19.5 Briggs mower surges

Your valves need adjustment

Ignition switch

What was the issue

Valves

try a new battery

Battery is to weak

valve adj.