Troy Bilt Bronco hard to spin over

semimechanicman

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It has a single cylinder 19 horsepower briggs and stratton. 2018 year model. Will post model number later.

So when you turn the key, it gets stuck like it has too much compression. Sometimes the starter will make it through and allow it to start. But most of the time the starter just gets stuck. The engine also sometimes goes backwards after the first spin of engaging the starter. Any help is appreciated
 

semimechanicman

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It has a single cylinder 19 horsepower briggs and stratton. 2018 year model. Will post model number later.

So when you turn the key, it gets stuck like it has too much compression. Sometimes the starter will make it through and allow it to start. But most of the time the starter just gets stuck. The engine also sometimes goes backwards after the first spin of engaging the starter. Any help is appreciated
I have also replaced the starter, solenoid and battery.
 

ILENGINE

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First step would be to remove the valve cover and make sure the valve clearances are set correctly. .004-.006 for both valves is a good starting point. After confirming they are set within spec, then you can replace the valve cover and see it is fixed. Still having issues would point toward the other major issue with the Briggs singles which is the compression release is broken on the camshaft and will need to be replaced.
 

semimechanicman

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First step would be to remove the valve cover and make sure the valve clearances are set correctly. .004-.006 for both valves is a good starting point. After confirming they are set within spec, then you can replace the valve cover and see it is fixed. Still having issues would point toward the other major issue with the Briggs singles which is the compression release is broken on the camshaft and will need to be replaced.
Thanks i will do that. But it does start after a few tries so would it still be valves?
 

bertsmobile1

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Yes
once started they will run with valve lashes so wide that the pushrods will fall off when going over bumps.
 

StarTech

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Thanks i will do that. But it does start after a few tries so would it still be valves?
Yes. As Bert sometimes the rocker clearances are so large that push rods can fall out but it is nearly triple of the spec. With some engines using valve stem caps (buttons) even they can fall off. Most 31 series uses them.

Briggs uses a weak starter on these engine; therefore, they use an ACR (automatic compression relief) on the camshaft. It is a poor design and tends to break off leading to full compression at start up. I adjust the valve to their minimum specs (OHV tends open these clearances as the engine wears). IN .003-.005 EX .005-.007). Note the intake is the one fartherest away from the flywheel. It also has an aluminum push rod. This aluminum needs to be checked for wear where it passes the push rod guide. If worn replace it. Once adjusted you rotate the engine the TDC compression by hand watching the intake rocker a slight opening (bump) just as you approach TDC compression stroke. If not present with the valve adjusted properly then the ACR has failed and is laying in engine along any other damage parts.

Don't be attempted to install a Chinese aftermarket camshaft either as they are junk. But Briggs currently have these camshafts on back order until Christmas.
 
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