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Small Engines (Lawn Mowers, etc.)/briggs & stratton intek 17.5 hp motor


My 17.5 intek motor will crank but not start. It is getting fuel and good spark, and tried starting fluid and still won't start, and I checked the compression and is showing low compression. I took off flywheel to check for sheared pin, but was good. What would you suggest it might be or what direction should i look at going forward.



Spark plugs.  If you know you have fuel and spark then it should start.  Briggs rarely publishes compression specs due to variations across engines.

Per the Briggs manual,
Testing Engine Compression

When your engine has leaks around the valves or rings, compression of the air-fuel mixture suffers. When this happens, performance and efficiency can drop dramatically. A spin of the flywheel will tell you whether the compression in your engine is sufficient.

1.  Disconnect the spark plug lead and secure it away from the spark plug. Remove the blower housing. Then, disconnect the brake pad or band, if equipped (see "Servicing the Brake").

2. Spin the flywheel counter-clockwise by hand (image A). If compression is adequate, the flywheel should rebound sharply. Weak or nonexistent rebound indicates poor compression (see "Troubleshooting" for a list of possible causes and remedies).

It does not take much compression for the engine to run.  Better (higher) compression usually equals more power and an effecient engine.

If you know for sure you have spark and it will not start on starting fluid I'd suspect compression or timing.  You verified timing via the flywheel key.  This leave compression to be the problem.  However, low compression, to the point a Briggs will not start at all is rare unless a valve is stuck, head gasket blown, or a broken rod.  Most of these symptoms are pretty obvious and easy to troubleshoot with a compression gauge...if you have 50-90 PSI the parts (compression) is good to start.  To check the valves you can just remove the valve cover and turn the the valves move.

I suspect there is an ignition or fuel problem.  Most likely a fuel problem...a leaking gasket.

Let me know if the engine snaps back per the Briggs compression test directions.

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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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