OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs and Stratton 28q777 Vibration

I have been watching this forum with interest and I am hoping someone out there can help. I have a Cox Kingcat with a single cylinder 16hp Vanguard engine. I have serious vibration problems. I have disconnected and removed the clutch and the drive pulley for the hydrostatic to eliminate these parts so there is nothing on the end of the crankshaft. Faulty crankshaft I thought, out came the engine and I removed the shaft. No had it checked at a crankshaft place and it is true. The machine runs well with no smoke and plenty of power. Only thing I can think of now is the harmonic balancer ( flywheel ) is out of balance but I can't see that happening, Any suggestions out there? Thanks for any help.

These engines have a 'synchro-balance' system fitted to most engines (some manufacturers for some strange reason option their engines without it to save money) which you should have seen when you had it apart.

Synchro-Balance consists of two big cast iron weights which are eccentric on the crankshaft held together by a long 1/4 unf bolt and small conrod to mounting on the inside of the crankcase. Was it all there and in ok condition?

Also check for fatigue cracks on the chassis itself where the engine bolts on

If you decide to change the flywheel you should be able to pick up a good second hand one fairly easily but make sure the ring gear is ok and of the same material you already have (they are either plastic or metal ring gears)

Thanks MST for your assistance. I have looked at the parts list for my engine and it seems that the newer versions of this engine did away with the counter balance. There are three pictures of the crankshaft and two show some type of counter balance as you suggested but after 1999 it seems there is only the crankshaft. There are no cracks in the chassis where the engine mounts, I might try some local repairers re. your suggestion on the flywheel or I may just bite the bullet and take the engine to a small engine repairer. I was somewhat annoyed at the reaction by most of the mower repair shops, it was basically you need a new engine it will be about $2000 please thank you.

Kingcat,

You will find that most mower shop will only be interested in selling new equipment as the older ones need knowledge base to repair and take some time to do.

Thanks Bruce, Yes probably cause I am a tradesman from the old school and like to repair things rather than tossing them out. God I sound like one of these guys on the grumpy old men series. I will fix it though by hook or by crook.

Kingcat

Kingcat,

I hope all goes well with the repair.

I too am from the old school. :Wavey: These days if the younger ones are challenged to use their brain they find it too hard and it is easier to replace rather than to fix and gain a bit of knowledge.

Computers are great for reference material but they still can't replace the hands on approach.

Well MST you were right, there should be a synchro balance system there and it has been removed at some time in the past. It took me a while to find this out as the manual for my model of engine states it shouldn't be there at all!!! Possibly the crankshaft ( or the engine ) has been changed at one time and the only one available required the balance assy. Anyway I have one on order and will post when I complete the job. Thanks to you all.

No Probs kingcat.

As I stated previously, there is a small number out there without the synchro balance. Some manufacturers order the engines without them to save costs, and rely on the chassis to be strong enough to withstand the vibrations.

Cost cutting by Cox I would say, it was probably never fitted from new . . . . I have seen this from a few manufacturers which I will not name!