Shaking Briggs 16

[Brettw 1,134]

I picked up a 7116 earlier this year, and it has been doing some leaf vac duty.  The engine starts and runs great,  lots of power, no smoke or issues.  However, there are two things that I need to deal with, and they may be related.  It has a slight oil leak that I believe is coming from the pan gasket.  And lastly it shakes.  I mean it isn't a smooth engine.  I cleaned up and set up a 7116 from my BIL, and it runs very smooth.  I know that there is a counter balance in these, is there not?  And if someone was inside the motor and did not make sure it was installed or installed correctly, could that be the issue?  I suspect this, because of the pan gasket leak leads me to believe someone may have been inside this engine.  

Edited November 27, 2016 by Brettw

[720nut 4,225]

Not for sure but first thing I'ld look for  Just my $.02

 

[BLT 718]

The synchro-balance weight is in the cover and the timing does not require the oil pan to be removed. It starts off with the head removed and the piston at TDC.  It's possible that the weight could be off if you didn't pin the weight to stay in place when installing the cover.

[MrSteele 492]

Had a similar problem with a 15 HP Crapsman a few years ago. Went to the effort of removing the engine and looking at the weight. Everything fine. Noticed while removing the oil pan that a couple of bolts were loose, and one completely gone. Put it back together with a new gasket, and no more problem. Before removing engine, you thought the engine was going to jump out from under the hood.

 

[MikeES 458]

Also make sure it is not the drive shaft coupling/flex disk that is out of alignment or bent.

[theniteowl 29]

Ditto on what Mike said.

I picked up a B112 that had a really bad vibration to it but ran well.  I had to tear the whole tractor apart doing various bits of work and I found that at some point one of the driveshaft bolts into the engine coupler had come out at one point causing the driveshaft to *** sideways while running causing a lot of wear against part of the hydraulic lift arm and the drive shaft.
The flex disk was also worn out of round on one side of the bolt hole so when the guy put it back together the disk was shifted bit out of alignment before being tightened causing the heavy vibration.  I replaced the disk and it smoothed right out but then I took it apart again and powder coated the coupler and drive shaft.  When I put it back together I found that the original bolt hole had the end threads stripped out from the previous incident and it just would not tighten enough for my comfort so I put in a 1/4" longer bolt.  Now I have vibration again apparently because the bolt on one side is a different weight than the other.

It's a relatively easy test.  Unbolt the drive shaft and see how she runs.

[Brettw 1,134]

Thanks guys.  She's in hibernation now, up in the garden shed, but I will check it out this spring.  Only a few more vibrations runs to be made until then, as I do try to run them for 15 minutes or so every three weeks to a month.

[GardenTrACtorguy 29]

If it wouldn't be internal problems I would maybe check your engine mounts.  Just my 0.02 cents.