Briggs and Stratton 17.5 hp won't start and backfires

dougand3

Well-Known Member
Joined
Mar 10, 2012
Threads
12
Messages
437
  • / Briggs and Stratton 17.5 hp won't start and backfires
Search ebay "Briggs 31C707 head" - some $25-35 ones. Search ebay "Briggs 796026". Look at the seller feedback # and read some reviews to find your trustworthy quotient.
 

Tinkerer200

Well-Known Member
Joined
Mar 14, 2015
Threads
4
Messages
913
  • / Briggs and Stratton 17.5 hp won't start and backfires
East Central Illinois, I have a used head myself but shipping would be more than the head. I have traded, rebuilt and sold engines all over this area until I "retired" about 5 years ago as I am 86. May be higher on east coast but likely you are not looking in the right places, small one man shops in out lying towns.

Walt Conner
 

njswede

Member
Joined
Oct 22, 2019
Threads
1
Messages
12
  • / Briggs and Stratton 17.5 hp won't start and backfires
I can get a new one from Amazon Prime for $142 shipped and that includes all screws and gaskets. Almost the same as a used one of you include shipping...
 

Tinkerer200

Well-Known Member
Joined
Mar 14, 2015
Threads
4
Messages
913
  • / Briggs and Stratton 17.5 hp won't start and backfires
I can get a new one from Amazon Prime for $142 shipped and that includes all screws and gaskets. Almost the same as a used one of you include shipping...

Which is why I did not suggest getting one from me but shop your area. Actually, the best deal is often buying a "junk" mower with running engine. Deck gone bad, bad hydro, etc. And frankly I don't want to mess with boxing up, taking to PO, etc.

Walt Conner
 

njswede

Member
Joined
Oct 22, 2019
Threads
1
Messages
12
  • / Briggs and Stratton 17.5 hp won't start and backfires
I can't believe I didn't think of this simple test before: I put the head back on but didn't attach the pushrods, leaving the valves closed. Then I spun the flywheel by hand and could clearly hear air rushing backwards through the intake.

OK. So it's the head/valves. I'm thinking it got overheated and warped either the valve or seat. Either way, I'm getting a whole new head/valve assembly. Done messing with this now.
 

njswede

Member
Joined
Oct 22, 2019
Threads
1
Messages
12
  • / Briggs and Stratton 17.5 hp won't start and backfires
Which is why I did not suggest getting one from me but shop your area. Actually, the best deal is often buying a "junk" mower with running engine. Deck gone bad, bad hydro, etc. And frankly I don't want to mess with boxing up, taking to PO, etc.

Walt Conner

Yeah... I'm done messing with this for now. Just getting the original part with all the accessories shipped seems like the least amount of pain.

Thanks everyone who's helped with ideas!
 
Top