Briggs and Stratton 12HP Clanking/tinkling sound

macadameane · 09-11-2009, 10:58 AM

Its a long story, but I'll try to sum it up. This is a B&S 281707-0415-01 12HP engine for a riding mower from 1992.

My engine wasn't starting well and burning a lot of oil. First I replaced carb parts and cleaned carb. Soon I had a really hard time starting it, so I took it apart, replaced the piston rings (which were badly worn), lapped the valves, cleaned, and reassembled (with new gaskets etc) and proper torque values.

I was finally able to start it (with the aid of carb cleaner again) but much quicker. It is not idling well (but this is less of a concern for me). There is a faint sound (like metal-buttoned overalls in the dryer, but quieter). I ran it for 20 min in hopes that the piston rings would seat better. In addition to this strange clanking sound, I am getting gas in my oil (but only since I ran it for 20 min). I have had the gas hooked up for many days after putting it back together without any leakage into the oil.

Any ideas for either of these problems?

Here is the parts diagram if you are interested:
Engine Model # 281707-0415-01 Illustrated Parts List

**Basementgeek** · 09-15-2009, 09:05 AM

Sorry no one got back to you.

Did you get your problems figured out ?

On the gas in the oil, got to be needle/seat/float settings are off.

BG

macadameane · 09-15-2009, 12:22 PM

When I rebuilt the carb, I checked the float and it seemed fine (and replaced the needle.

I hear that rust can occur from watery gas and cause the needle not to seat properly, but this isn't the case here. It only happened after I started it up and ran it for 20 min. Some on other sites have said to check the intake valve;s clearance. I forgot to do this (since I relapped the valves). I might need to grind the valve stem down a bit. Perhaps during compression, gas is getting forced into the crankcase this way (but I'm no pro).

The carb does need to be adjusted and tuned though. Even so, I want to get to the bottom of the clanking first.

**Basementgeek** · 09-15-2009, 03:17 PM

I have no idea what that "tinny" sound you are hearing is. Can you remove the cover and run it to see if you still hear it?

BG

macadameane · 09-15-2009, 05:28 PM

What cover are you talking about? I started it without the air filter/cover on.

It sounds link a clanking sound inside the crankcase, but I'm not sure that that is its source.

Wish I could get a sound recording of it, but I think a lo-fi recording would not help much.

One thing's for sure, I'll be buying new gaskets again.

**Basementgeek** · 09-15-2009, 08:09 PM

I was referring to the blower cover. I no clue what inside the engine could be making that noisy.

BG

digger350 · 09-20-2009, 02:46 PM

sounds like its about to throw a rod the connecting rod may be loose about to break

macadameane · 09-21-2009, 07:24 AM

Quote:

Originally Posted by digger350

sounds like its about to throw a rod the connecting rod may be loose about to break

Its not that, we torqued that thing down to specs. Also the sound isn't as fast as the piston should be moving. A few have suggsted it is a valve clearance issue (since I lapped them and the valve may be not closing all the way. That may even cause both problems.

**K-B** · 09-22-2009, 07:39 AM

If all you did was lap it, as long as you re-set the valve clearance you shouldn't have to grind the valve stem.

macadameane · 09-23-2009, 08:51 AM

The clearance can't be adjusted that way. Cam pushes the tappets, tappets push the valves. Thats all there is to it.

**K-B** · 09-23-2009, 11:32 AM

I'm sorry, I hadn't even bothered to look at the diagram. I was thinking it was an OHV.

09-11-2009, 10:58 AM	#1 (permalink)
macadameane Registered User Join Date: Dec 2008 Posts: 14 OS: Windows XP SP3	Briggs and Stratton 12HP Clanking/tinkling sound Its a long story, but I'll try to sum it up. This is a B&S 281707-0415-01 12HP engine for a riding mower from 1992. My engine wasn't starting well and burning a lot of oil. First I replaced carb parts and cleaned carb. Soon I had a really hard time starting it, so I took it apart, replaced the piston rings (which were badly worn), lapped the valves, cleaned, and reassembled (with new gaskets etc) and proper torque values. I was finally able to start it (with the aid of carb cleaner again) but much quicker. It is not idling well (but this is less of a concern for me). There is a faint sound (like metal-buttoned overalls in the dryer, but quieter). I ran it for 20 min in hopes that the piston rings would seat better. In addition to this strange clanking sound, I am getting gas in my oil (but only since I ran it for 20 min). I have had the gas hooked up for many days after putting it back together without any leakage into the oil. Any ideas for either of these problems? Here is the parts diagram if you are interested: Engine Model # 281707-0415-01 Illustrated Parts List

09-15-2009, 09:05 AM	#2 (permalink)
Basementgeek Moderator, Home Support Join Date: Feb 2005 Location: Central Ohio, USA Posts: 1,483 OS: XP Pro SP2/Vista Ultimate SP2 Blog Entries: 3	Re: Briggs and Stratton 12HP Clanking/tinkling sound Sorry no one got back to you. Did you get your problems figured out ? On the gas in the oil, got to be needle/seat/float settings are off. BG __________________ Donating to the forum keeps TSF free for all. Proud member of ASAP

09-15-2009, 12:22 PM	#3 (permalink)
macadameane Registered User Join Date: Dec 2008 Posts: 14 OS: Windows XP SP3	Re: Briggs and Stratton 12HP Clanking/tinkling sound When I rebuilt the carb, I checked the float and it seemed fine (and replaced the needle. I hear that rust can occur from watery gas and cause the needle not to seat properly, but this isn't the case here. It only happened after I started it up and ran it for 20 min. Some on other sites have said to check the intake valve;s clearance. I forgot to do this (since I relapped the valves). I might need to grind the valve stem down a bit. Perhaps during compression, gas is getting forced into the crankcase this way (but I'm no pro). The carb does need to be adjusted and tuned though. Even so, I want to get to the bottom of the clanking first. Last edited by macadameane; 09-15-2009 at 12:28 PM.

09-15-2009, 03:17 PM	#4 (permalink)
Basementgeek Moderator, Home Support Join Date: Feb 2005 Location: Central Ohio, USA Posts: 1,483 OS: XP Pro SP2/Vista Ultimate SP2 Blog Entries: 3	Re: Briggs and Stratton 12HP Clanking/tinkling sound I have no idea what that "tinny" sound you are hearing is. Can you remove the cover and run it to see if you still hear it? BG __________________ Donating to the forum keeps TSF free for all. Proud member of ASAP

09-15-2009, 05:28 PM	#5 (permalink)
macadameane Registered User Join Date: Dec 2008 Posts: 14 OS: Windows XP SP3	Re: Briggs and Stratton 12HP Clanking/tinkling sound What cover are you talking about? I started it without the air filter/cover on. It sounds link a clanking sound inside the crankcase, but I'm not sure that that is its source. Wish I could get a sound recording of it, but I think a lo-fi recording would not help much. One thing's for sure, I'll be buying new gaskets again.

09-15-2009, 08:09 PM	#6 (permalink)
Basementgeek Moderator, Home Support Join Date: Feb 2005 Location: Central Ohio, USA Posts: 1,483 OS: XP Pro SP2/Vista Ultimate SP2 Blog Entries: 3	Re: Briggs and Stratton 12HP Clanking/tinkling sound I was referring to the blower cover. I no clue what inside the engine could be making that noisy. BG __________________ Donating to the forum keeps TSF free for all. Proud member of ASAP

09-20-2009, 02:46 PM	#7 (permalink)
digger350 Registered User Join Date: Aug 2009 Posts: 14 OS: xp	Re: Briggs and Stratton 12HP Clanking/tinkling sound sounds like its about to throw a rod the connecting rod may be loose about to break

09-22-2009, 07:39 AM	#9 (permalink)
K-B Moderator, Linux Join Date: Oct 2005 Location: NY Posts: 2,876 OS: Vista, Ubuntu My System	Re: Briggs and Stratton 12HP Clanking/tinkling sound If all you did was lap it, as long as you re-set the valve clearance you shouldn't have to grind the valve stem. __________________

09-23-2009, 08:51 AM	#10 (permalink)
macadameane Registered User Join Date: Dec 2008 Posts: 14 OS: Windows XP SP3	Re: Briggs and Stratton 12HP Clanking/tinkling sound The clearance can't be adjusted that way. Cam pushes the tappets, tappets push the valves. Thats all there is to it.

09-23-2009, 11:32 AM	#11 (permalink)
K-B Moderator, Linux Join Date: Oct 2005 Location: NY Posts: 2,876 OS: Vista, Ubuntu My System	Re: Briggs and Stratton 12HP Clanking/tinkling sound I'm sorry, I hadn't even bothered to look at the diagram. I was thinking it was an OHV. __________________