Mowed the lawn today 9/27/14 and am getting some wierd noises from it. At high rpms doesn't sound too bad but at half throttle to low makes a noise like "CLUNG, CLUNG, CLUNG.' Rpms go up and down between clungs. I know it means engine work but where to look first? Can't be the crankshaft because two pulleys come off the shaft. Any ideas? Valves? Pushrods? 13.5 Briggs. Fall/Winter project.
Makes the noise without the mower deck engaged.
Walloped a tree trunk during mowing, rpms went way low but didn't stall.
I ve got a 17.5 twin cylinder. Had issues with rpm hunting. Would nt keep steady idle. Found trash in main jet of carb. You ll have to take off fuel bowl and blow it out. Should take care of it.
maybe, but the carb doesn't seem to be the problem. it's that CLUNG sound that's throwing me. Fish said it could be the crankshaft counter wieght. anyway I got half of the engine dismantled already. valves and pushrods are still in one piece. there's nothing hitting the piston. Looking at the crankshaft diagram, I can't figure out how the counter weight is "fastened" in the crankshaft housing. Does it free float? What's the purpose of that link inside?
I doubt that you have an internal problem. I'm not there to hear it, but I also feel you have a fuel problem. My thoughts go to carb loading one cylinder (mixture way to rich) not allowing for combustion in that cylinder. This causes an unbalance in power strokes and that is what you are hearing. If after you have the engine reassembled the problem still exists, look at the carb and ignition systems.
That's what I get when there are two different problems on different engines in the same thread. Sorry about that, I combined and interchanged engines.
Everything is back together. Nothing was broken inside. Had some problems understanding the extra lobe on the exhaust valve camshaft, but thats straightened out. I wrote Briggs with the serial number and they said the engine required two valve stem caps. I could only find one. So I adjusted the valves with one cap on and one cap off and it still works, BUT for how long before the valve stem gets rounded out?
I thought I had a problem with the carb shut down solenoid. With it off, my air cleaner housing would fill up with gas.. After getting rid of the gas, I installed a shut off valve just before the carb. So now as extra insurance, when I shut down I close the manual valve.
When I received the proper engine pulley which slid right on the motor shaft I forgot to check clearance all around the pully. Wouldn't you know it, I made a boo-boo! But the pulley slide right on up! Has a son of a time getting the belt around the other pulleys, even by hand with a socket and breaker bar. The starter wouldn't crank the engine. Then I spotted the mistake. The belt was on that front belt guide right next to the pulley. So, back off the bolt and slide the pulley down just enough to get the belt back in the groove. Bolted back up and everything works now. Next I got to tackle the midpoint idler and spring. Fell off yesterday. Then I should be ready to go! Thanks to everyone involved with my project.
