Sure, if you send me the model number of the engine. There are several 18 hp B&S engines and I don't do lookups. Walt Conner wconner5 at verizon dot net

Yeah, address below, put in proper format, remind me of engine and what you want. Walt Conner wconner5 at verizon dot net

thanks for the tip. i was sort of afraid it was going to be the carb. i added stabil to the fresh fuel just now and according to it - it has some sort of cleaner in it. is this what you are talking about to try first, or is there a different carb solution to be added to the fuel? beacuse the stabil thing didnt really work - it almost got worse. i saw at home depot a spray can of something called "carburator cleaner" but i dont think that is to be added to the fuel - more like to spray somewhere, or possibly use during carb rebuild? second question, if I were to rebuild the carburetor - what would you suggest? I've never done it, how hard is it to figure out by following online instructions? i just looked up parts - rebuild kit is $15-20 and time it takes to learn and do it. the new carb is $150-$160 but could just plug and play. if i were to take on rebuilding it myself - would i need any specialized tools? if i were to take off the carb and take it to someone to rebuild it - how much would that typically cost? thanks again - trying to weigh options as the branches are piling up...

I have owned an opposed twin on an old Gilson for about 20 years and it has a knocking sound when idling with no load. The knock disappears when the blades are engaged at idle. The knock cannot be detected at high speed - load or no load. I believe this is a characteristic of the vertical opposed twins with splash lubrication. They seem to run forever. Opposed twins with full pressure lubrication are as smooth and quiet as any engine out there - no knock. the question is - Are you describing the characteristic knock - or do you have something more serious. As mentioned, cleaning the head carbon is a good idea and it is easy to clean. Change the oil to SAE 30. Make sure the oil level is maintained in the operating range. Make sure the dip stick is screwed down and not simply rested on the dip stick housing. If your engine does have a serious problem, there are many good engines remaining on expired equipment. Cooling fins must be kept clean to reduce the possibility of a valve seat failure. A Murray mower is not worth the expense of a new short block - even if you can find one.