Engine Knock, Briggs & Stratton 18 HP
I did some repairs on a ten year old Murray Lawn Tractor with an opposing twin cylinder 18 HP B&S engine (serial no. 42A707 Type 1238).
This engine was apparently switched at some point - don't know how old the engine is. The tractor body says 17 HP Twin II (Murray, 46" cut, Automatic Drive).
Wasn't running when he dropped it off to me. Is running now and it has a loud metallic knock of some kind and in sync with the engine cylinder firing, which I only notice when first starting it up and idling.
I had assume it was a crankshaft rod knocking from worn bearings (only have automotive engine experience), but someone pointed out that it doesn't have rod bearings (but no chance for more discussion on the phone with that person).
I'm wondering if anyone is familiar with my description of the problem, and could tell me what my options are. A B&S service rep told me that Briggs doesn't offer a short block for this serial no. anymore - something to do with emissions non-compliance.
Thx very much for any help,