Sudden over revving Briggs and Stratton

[bcliquidforce]

I have a Craftsman lawn tractor, 21 hp Briggs and Stratton, model 331877-0869-g5. Was mowing and all was good, pulled into garage and engine started revving at high speed. Have started a few times since, always goes super high rpm, the outside governor arm doesn't move, but I moved it by hand and it slows the rpm's down. Moves freely and everything outside is tight, so I thought the governor gears stripped, possibly. Took it apart, found governor gears look ok, and found this spring in the crankcase, it was a little tangled up but straightened it out. Trying to figure out if this spring goes on the governor or somewhere else, I can only assume it has something to do with the over revving issue. Thanks, Brian

 

[StarTech]

First the governor are damaged. As for the spring is off the camshaft ACR which means it is laying in pieces inside the crankcase. The governor flyweights most likely got jammed.

 

[bcliquidforce]

First the governor are damaged. As for the spring is off the camshaft ACR which means it is laying in pieces inside the crankcase. The governor flyweights most likely got jammed.

Are you saying the governor is bad? The weights move freely, gears look good, do you see something broken in the picture? Thanks, Brian

 

[StarTech]

Are you saying the governor is bad? The weights move freely, gears look good, do you see something broken in the picture? Thanks, Brian

Think about it. Any loose material inside can jammed the flyweights and then while you taking the engine dislodge..

But yes I see damage teeth. It could be even be bent. I have seen it where the ACR pieces got into the mating gear teeth on the camshaft and governor. It happen enough here that I stock both the camshaft and the governor/oil slinger.

 

[bertsmobile1]

You won't see it if you don't know what to look for
That is the difference between techs and home handymen

 

[bcliquidforce]

Star Tech, thank you very much. Bertsmobile1, the purpose of a forum is to share information, likely, I don't have as much knowledge as you on small engines and that's why I am here. If you have a business, your attitude is probably driving people away, I assume. I have been an electromechanical tech for years, PC's, scales, all kinds of printers, alarm systems, UPS's, servers, switches and routers in computer rooms, meat labelers, conveyor systems in warehouses, forklifts, etc. My small engine knowledge is improving. A history, of this engine, and lawnmower, bought it about 10 years ago at a Sears Outlet for about $1000, and they said it had been returned and refurbished, lie, lie, lie, it burned oil from day one, got worse over the years, but I am happy I got 10 years of use out of it. The deck, trans, frame, all still ok, so now that the ACR has came apart, seems to be a common problem, thanks Star Tech, found more loose parts inside, I have decided, that since it has been burning oil for it's whole life, to rebuild it would require a governor, camshaft, unknown on the rings, piston, cylinder, cylinder head, gaskets, valves, it's not worth it, so I bought a replacement engine, new, and I hopefully will get another 10 years out of it or more. So, again, thanks Star Tech, and Bertsmobile1, If you can't contribute any more than criticism, STFU

 

[sgkent]

If you can't contribute any more than criticism, STFU

Okkkkaaaayyy. No one else posted but the two guys whom you praised. Are you here on the forum under multiple aliases? There are people here like myself who spent maybe an hour, hour and a half trying to find that part in the drawings but said nothing because we didn't know. The last sentence you wrote is rather an eyebrow raiser.

 

[bertsmobile1]

Not a criticism, a fact .
Try to tell me you do not do a call out and see a dozen problems with equipment that the customer has not noticed .
I have walked more people through repairing their equipment than you have had hot breakfasts and this includes a lot of disabled people many of which were functionally illiterate , both here & in person.
When customers ask I show them what needs to be done & tell them how to do it to the point that the they become the only customers I loose because they realize just how easy mower repairs are when you know what to do but the bulk of them buy parts from me and long term I would prefer to sell & $1000 of parts a week rather than $ 2000 of labour as I am over 70.

And the proof of the pudding is you posted the photo of what you thought was a good governor & Star picked the broken teeth.
I am in Australia so by the time I saw the photo Star had already drawn your attention to the bad teeth which you had not seen because you never thought about checking them .
Techs do see it because we pull engines apart to replace the broken ACR and then check the gear for damage .
So we know what to look for where as Joe Average would have replaced the damaged cam then a short time latter the governor will fail , engine will race away and the con rod breaks totalling the engine.
They then come here swearing blue that XYZ brand of engines are junk.

We are here (and that includes me ) to prevent this happening .
If you want to take offence and believe that every one who states a fact is making a person attack on you then you have my sympathy because that makes for a myserable life

 

[StarTech]

Being a 330000 series most likely the oil burning was the result of a blown head gasket these engines are known for as are they known for camshaft failures. The problem with camshaft is a design flaw which Briggs has never corrected. If you do change your mind about the repair avoid buying a Chinese after market camshaft. They are problematic to say the least. I tried them and the ones I got had to be reworked to even fit the engine. That was 6 months ago and one has already failed.

I have a lot experience working on a lot things but I am no expert on everything, never will claim to be. Started out working office calculators in '79 then went to typewriters and copiers. Then later I went into the financial field of bank equipment and forms handling equipment This include the high speed line printers

Heck 62 I just learned how the gearbox of Stihl trimmers apart and that took working with another tech that had experience in that area. Everyday I learn something to prove to myself that I am still alive. One thing that I have learn in the 43 yrs and that is to ask for when it is needed.

 

[slomo]

bcliquidforce, I see you are new here. Welcome to the best mower forum on the internet.​

Far as Bertsmobile1 goes, that guy, in my opinion, is a walking genius. He is very straight up in your face but always correct. I have to admit, at first I was a little turned off buy him. I actually read and listened to his thoughts/messages/wisdom he was putting out. Lets just say he is stunning at what he shares here. And we only read about 20% of his knowledge on here. Dude is scary smart. If Bert says the sky is orange, place your bets on him. Give Bert a chance. He won't steer you wrong. End of message.