Briggs Stratton 326437

We got a 7.5 kva alternator (Dunlite out of Oz) powered by one of these (16 hp side valve with balance shaft) second hand. Alternator is direct coupled to the engine so only one bearing. Known history - the alternator and motor had both been overhauled just prior to getting it - but the overhauler (a small equipment outfit) mightn't have been that good by some things I've found on this dismantle. It has had only intermittent use since.

Question is - do they all vibrate badly? This one has shaken the roll cage off the frame, shaken a wire off the rotor and a leg off the flywheel diode in the alternator.

And I've just found that the magneto end crank bearing has play in it. Which might have had to do with the bolts fastening the alternator to the engine being slightly too long and bottoming out before the flsnge was really tight. (Both engine and alternator are bolted to a base plate as well though).

The base plate has been adapted so it sits on a tyre in the roll cage as an anti-vigration measure.

Is this the nature of the beast or do I need to know more about that balance system? I'll have to go in there to replace the bearings so will have to find a manual.

Thanks in anticipation for any help and any pointers to a manual

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Synchro Balance

Bob

Thank you very much - I'd have been bloody lucky to get that right by fluke!

There's an "out of production" Briggs manual that covers those engines, but the link I posted is FREE.

GOOD engines, but shake terribly when "overhauled" by "BLEMS"!

Bob,

Thanks again for the link. I've explored some.

I'd say I found that manual listed on the B & S site ($23)and I'm checking to see whether our local librarian can get hold of it via the technical training school system here. The aim was to find out what I am dealing with and your link will do that.

I won't get inside this one for a while but will update on what I find.

It fully fits in with an expression we have here involving shaking and nails and a certain structure shape if you get the gist.

I put a somewhat updated post of this over at RP but haven't generated any response there as yet.

Though I'm not a fan of B & S I find it hard to believe they let it go out of the factory like this.

Bob,

Now I know what to look for.

I haven't stripped it yet but looks like the balance is timed about half a crank turn out.

Update

It was a "high class repair" somewhere in its career. First the balance weight out of time.

But then there was the oil leak on the alternator side - due to the complete lack of the oil seal that should have been there.

The engine now seems to work fine. The alternator seems to be a basket case as the rotor seems to test ok stationary and do bad things when running. Maybe one more try or another alternator.

I'm glad to here you got rid of the shakes!

Sometimes, a guy's gotta wonder just what guys are thinking when they mess something up like that!

Bob,

Yes - and then have the hide to charge for doing it!