Problems with the cutting deck

before you go too far, remove the pulley, replace the bolt then run the engine to check it is in fact the pulley & not the crankshaft .
Fi the pulley is just warped then holding it upside down in your vice do some mechanical rectification with a block of hardwood & a big hammer
 
It's already in my plans to remove and evaluate, I haven't done this yet because the tractor stayed in place... I had to return with the empty trailer for another activity.
I even have to take measurements, as some sellers are private importers and have never seen a lawnmower tractor in operation and buy cat for rabbit is complicated.
I only found 3 "suppliers":
The Official Importer - USD$250
A private seller in another state - USD$173 + shipping
And a repair shop in another state - USD$140 + shipping.
Speaking of an official importer, I know the reason why he no longer imports the brand... is that Briggs&Stratton bought the company Branco, which is now supplying 3 models with Briggs engines under the name Branco (traditional manufacturer of small machines for the garden and field), a zero turn 25HP, a 19HP and a 17.5HP.
I'm waiting for an answer from Branco if they also use this pulley (708363).
 
Well... I ended up buying a new pulley... but... it also shows the same symptom, less so, but it does.
See that the lathe bench even vibrates at high speed (700RPM).
I'm asking B&S to find out what the vibration specification is to condemn the new pulley.

 
I don’t think that you are going to find any pulley that’s going to run perfectly true. Most are 2 piece of stamped steel that are either bolted or welded together. It awfully expensive to make a pulley out of solid stock and machine it down.
 
This appears not to be made of two halves but rather hot formed and then welded to the shaft I believe in a standard form and welded by machine... even so, there is human interference in the operation, where the greatest probability of error lies... perhaps in the rush to produce.
 
As consumers we are in a bad spot...
B&S USA referred me to technical assistance.
B&S Brasil, paid me a lot of attention, but couldn't say anything about the specification and couldn't even test another one from stock, as here they only sell it for the 17.5Hp engine, which according to them is different.
I'm going to return the new pulley, because not even the store that sold it to me can say anything...

I'm seeing if any company that works with industrial balancing can solve the problem with the original pulley.
 
No company returned positive information, always a “maybe” or “could be” and I will not pay for transportation and service that way.
I returned the purchased part and worked on the old one, achieving a good result... better than the new one, but only in the oscillation of the pulleys, as I have no way of checking the balance, but the improvement was noticeable both on the lathe and assembled.


But there is still a constant vibration of the motor assembly, which I believe is due to flexion of the tray where it is sitting, as it is 2.8mm and appears to be flexing.
Lateral trator com motor.jpg

What do you think?
 
Well, I think I'm on the right path...
The base where the engine sits is actually flexing.
I made a support for the front part of the engine, just below the valve adjustment cover and the improvement was significant...

m_20230925_174336.jpg


The deck vibration is now becoming acceptable...
But if the shaft is not bent and the pulley now has no more "play", I can only imagine something unbalanced inside the engine... what could it be???
 
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