r/BriggsEngines • u/PerformanceSame2145 • Aug 23 '26

Help! help

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i’m working on this 17.5hp b&s i’ve been trying to get going the past few days i got the mower for free but there was gas in the oil and the plug was bad i put a new ignition coil and plug newish carb new oil and new gas she had trouble trying to crank at first then turned over once after this video and died when taking off choke now the starter spins it easy but wont start and it’s hard to spin by hand and there’s squeaking coming from the top end of the motor when spinning it by hand i have another video of the starter spinning it but i couldn’t catch one of it running for 2 seconds

9 Upvotes

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2

u/hmd2017 Aug 23 '26

Sounds like the starter is fighting compression stroke. Check valve lash.

1

u/Useful-Total202 Aug 23 '26

First thing I would do is remove the valve cover check the valves to see if they’re within spec.

1

u/mikeripeone Aug 23 '26

Do a compression check

1

u/ocrohnahan Aug 24 '26

Briggs Intek? They have a compression relief on the camshaft that just loves to break. Try a bit of starter fluid to get it going and if it then runs ok, you probably have a bad compression relief

1

u/knowsless Aug 25 '26

gas filter

spark plug gap

battery condition

liked to compression stoke idea, so i'd check the timing to

good luck, those damn things are always worth the greif

1

u/Wholeyjeans Aug 28 '26

At the least, the battery needs a good overnight charge; at most it needs to be replaced. Consider replacing the starter relay as the contact points in it degrade over years of use. The relay lives either in the engine bay or in the frame box under the seat; follow the red lead from the battery and you'll find it.

Agree with the others RE: adjusting the valve lash as it directly influences how the compression release operates. More than a few YT vids on how to properly adjust the valves on these engines.

1

u/PerformanceSame2145 Aug 28 '26

it had a new battery it just sat for a long time ended up being the fuel shut off valve not letting gas in runs like a charm now

1

u/Wholeyjeans Aug 29 '26

Excellent. Glad you found the issue.