18.5 HP Craftsman Briggs and Stratton lawn tractor will not start

Old 07-30-15, 12:11 PM
Thread Starter
Join Date: May 2008
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
18.5 HP Craftsman Briggs and Stratton lawn tractor will not start

We have a 18.5 HP Craftsman lawn tractor with a Briggs and Stratton motor in it. The model # is 917.275821. I have no idea if any of these symptoms are related but I figured more info is better than less.

Earlier this year the mower started a bit tough but would start. However, once I reduced the choke after starting it would take almost a minute to go into a normal idling speed. I'm not sure of the best way to describe it, it would run kind of sluggish and slow until it would finally kick in and idle normally. Everything else would work fine after that.

My boyfriend was mowing the yard a few weeks ago and he said that it was making a "strange sound" so he shut it off. Since then it has not started again.

He replaced the battery, the solenoid, and the starter and still no luck. I took the 20 amp fuse out that's by the solenoid and checked that. It looks good but it didn't seem seated quite correctly. there was a ton of dust and dirt in there so I cleaned it out and it looks like it's in good now.

The mower has exhibited different symptoms in regards to what it sounds like when it won't start. Sometimes there is a whine for as long as you turn the key and sometimes it's just a click out of the starter. I can see that the starter does try to turn.

Voltage wise - 12.5 volts or so out of the battery, 11-12.5 volts coming into the solenoid, but only 2-3 coming out when the ignition is turned on. The old solenoid exhibited the same voltage readings. I can't get a voltage reading on the white wire on the solenoid but it may be because I can't make a connection on it - not sure.

I have disconnected the ground from the solenoid and used a jumper wire to verify that the ground is good. That didn't help either - assuming I connected the ground to the chassis well enough.

What's frustrating is I"m not sure if I can trust either the new battery or new solenoid. The battery can go from 70+% charged down to 10 with 3-4 starting attempts of the mower. That seems odd?

The solenoid I ordered was part # 146154 and it said it replaced the part # my manual showed of 178861.

Any help would be appreciated. Thanks.
Old 07-30-15, 07:02 PM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 27,475
Received 2,103 Upvotes on 1,882 Posts
How the machine sounded when it was running and the solenoid and battery are probably unrelated. Small lawnmower batteries can drain quickly so it is possibly that 10 hard crankings have drained the battery noticeably. If I had to guess the engine had troubles and that just makes starting more difficult.

Without knowing anything one of the most common problems is with a dirty carburetor. Dirty fuel and letting the machine sit for long periods (winter) are especially good at clogging the tiny passages and jets in the carburetor. A classic sign is when the engine needs the choke to run (more than just starting) or if it surges.

Post back with specifics of what the mower was doing before it died. Sounds, smoke, what it took to get it started or keep it running are all important clues. Once the engine is sorted out then we can get back to the battery and other starting stuff.
Old 07-30-15, 08:02 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 15,949
Received 138 Upvotes on 127 Posts
To me the story sounds like the engine ran out of oil. locked up, and now you hear amperage whining in the starter when you turn the key. Can you turn the engine by hand? The flywheel screen on top of the motor should by hand.

Thread Tools
Search this Thread
Ask a Question
Question Title: