QuestionI 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 strokes, which I only notice when idling.
I had assumed it was a crankshaft rod knocking from worn bearings (only have some 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).
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.
Someone suggested removing the heads and scraping carbon off the piston. You agree?
PlumDucky
AnswerDecarboning won't hurt but it won't fix your knock.
Pull the hood off and mow till she blows. You need to take the hood off so you can see it when it happens. It will be cool and no one will get hurt.
You think the EPA regs on small engines is bad now, thank god Al Gore isn't the pres.
Here is a great site to purchase non-compliant engines.
http://smallenginewarehouse.com/
