Jump to content

Nominations for Tractor of the Month
Garden Tractors and Parts on eBay



Photo
- - - - -

18 HP Briggs Flat Twin - Strange Sounds???


  • Please log in to reply
8 replies to this topic

#1 jdslednut OFFLINE  

jdslednut

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 77
  • 636 Thanks
  • 837 posts
  • Location: Winthrop, MN

Posted March 22, 2011 - 10:35 PM

I and a couple of my students are working on a B&S 18 Flathead Twin from the mid 80s. We installed it into a Schweiss mower (hyrdo driven zero-turn) and when the engine ran at low RPMs and especially when we killed it, it made quite a clatter noise, almost like a knock. We removed it and decided it would be better to go through it just to know before sending it out the door. Everything measures up like new. Rods are good, crank is good, rings are good, bearings are good. Any ideas? Is this characteristic of this engine as I have read on some forums? Do you think it is a response to low-end power to the hydro? Any ideas would be appreciated. I plan to redo the top end anyway - grind valves, new rings, and install new rods for piece of mind. Thanks, Jeff

#2 JoshBrown OFFLINE  

JoshBrown

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Member No: 1978
  • 20 Thanks
  • 277 posts
  • Location: Northeastern Kentucky

Posted March 22, 2011 - 11:12 PM

I have had several Opposed twin 18 hp briggs that really clatter when you shut them down. I suppose it is normal for the briggs. I had a 1996 18.5 briggs I/C that really did this sounded like it was knocking everytime I shut it off.

#3 jdslednut OFFLINE  

jdslednut

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 77
  • 636 Thanks
  • 837 posts
  • Location: Winthrop, MN

Posted March 22, 2011 - 11:31 PM

Thanks Josh. It's good to hear of others with the same experience. Anyone else have the same for a little more piece of mind? Or other experiences?

#4 Deck_Drive OFFLINE  

Deck_Drive

    collector of sears

  • Senior Member
  • GTt Junior
  • Member No: 736
  • 96 Thanks
  • 348 posts
  • Location: Cambridge MN

Posted March 23, 2011 - 03:28 PM

in the 3 or 4 briggs opposed twins I have owned. None of them made the clattering noise.

#5 JD DANNELS OFFLINE  

JD DANNELS

    Tractorholic

  • Senior Member
  • Member No: 2011
  • 3,786 Thanks
  • 3,907 posts
  • Location: Newton.Ia

Posted March 23, 2011 - 03:50 PM

I can't say for sure, but can tell you about my 22 HP Murray with The Briggs Vertical shaft. It did just what you describe.
I fixed it last Sunday. The front motor mount bolt was loose, the missing back bolt was found in a bunch of grass inside the frame rail. My only guess is the belt pulled fine while running and when shut off it caused the motor to bounce.
Lock tite and tourqing the bolts have solved my problem.

#6 DH1 OFFLINE  

DH1

    Electric Tractors

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 62
  • 4,587 Thanks
  • 5,295 posts
  • Location: Markham Ontario Canada

Posted March 23, 2011 - 04:20 PM

I have a 18hp B&S vert twin just like yours and no clatter at idle or when you shut it down.
JD DANNELS might have the answer there loose mount bolts.
When I do shut mine off just before it stops the whole mower shakes.

#7 NUTNDUN OFFLINE  

NUTNDUN

    Lost in Cyber Space

  • Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 3
  • 10,266 Thanks
  • 15,618 posts
  • Location: Pennsylvania

Posted March 23, 2011 - 06:49 PM

The opposed twins do seem to give more of a shake at the shut down then a single cylinder does. I don't know why other then more rotating mass. The Briggs vertical shaft 22hp in the Huskee we have sounds like crap all the time LOL.

#8 jdslednut OFFLINE  

jdslednut

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 77
  • 636 Thanks
  • 837 posts
  • Location: Winthrop, MN

Posted June 07, 2011 - 01:31 AM

Forgot to let you know what the problem was. The crank gear keyway was worn as well as the pin (key) in the crank. This gave quite a bit of slop in the gear and shot off the timing when run at low rpms. There was also a little to much end play as well. Engine ran like a top after the fixes. Let's just hope it keeps going for it's owner.

#9 NUTNDUN OFFLINE  

NUTNDUN

    Lost in Cyber Space

  • Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 3
  • 10,266 Thanks
  • 15,618 posts
  • Location: Pennsylvania

Posted June 07, 2011 - 08:52 AM

Forgot to let you know what the problem was. The crank gear keyway was worn as well as the pin (key) in the crank. This gave quite a bit of slop in the gear and shot off the timing when run at low rpms. There was also a little to much end play as well. Engine ran like a top after the fixes. Let's just hope it keeps going for it's owner.


Glad you got it figured out Jeff and thank you for posting the update :D




Top