rebuilt gear case & reassembled unit. knew engine service was next, but had not done anything to it yet.started engine **using ether** and it ran for about 45 seconds, screeched (not cylinder or crank seizing or any such) then died. pulled flywheel off, found **aluminum** keyway was sheared. had an extra on hand, installed it, reassemble and start again **using starting fluid** same occurrence: run, screetch, die. found keyway sheared off again.the keyway is aluminum to allow shear instead of shaft damage.is it my use of starting fluid? I will have to order some more keways before more testing. I will not use ether to start next time. any other possible causes?
If it ran for 45 seconds before shearing off, I'd look at the gear case rebuild. I don't know much about that particular machine, but I'd assume it's in neutral or otherwise unloaded when you start it right? Even if the ether gave it a torque boost at start it shouldn't shear anything when there's no resistance on the output. That it does shear seems like something is catching or dragging much more than it would in normal operation, and that it's sudden enough to not stall the engine but shear the keyway. Is there any chance something in the gearbox or between it and the engine are binding?
Grind down a piece of file to fit
Make sure its not binding up or stopping hard on anything and the engine is free to spin over. There is a one way bearing in the pull start on those old briggs that could possibly seize up if I remember right. You getting the flywheel good and tight? The taper should hold it tight without the key even being in there, the key just prevents it from slipping during operation unless it hits something extremely hard, and then it should shear to prevent the crank from becoming damaged. If it gets to taking too much time and effort to get the ol' Briggs running always remember that the Predator engines at HF are good, cheap, and parts are plentiful.
>>2877400>taper should hold it tight without the key even being in there, the key just prevents it from slipping during operationthis. youre not seating the flywheel well enough on installation
>>2877409>>2877378>>2877400in neutral and tines not engaged. all shafts turn freely whether engaged or neutral.concerning the use of ether, I was thinking of cylinder detonation, not increased torque.the predator is an option, but trying to get this one going with minimal investment. if another few keyways sacrifice themselves, I will probably go that route.
>>2877409he needs to get lapping compound and get a better fit
>>2877414i wouldnt even bother with that. get everything surgical clean and put a couple drops of green loctite on the interface and torque it down
Idk Briggs and Stratton motors but usually theres a special tool for flywheel removal instalation/removal on other engines I've worked on. Sheared Woodruff keys are from the flywheel not sitting on the tapered fit of the crankshaft. Crankshaft starts spinning Woodruff key slips out and is blown to bits, engine seizes. Find the flywheel installer tool or someone on YouTube that installed it some other way. It has to be really really tight. Even if you used something like a socket and rubber mallet it still won't hold once you gas it. Once it's under load of it is not seated properly it will come right off and keep shredding your Woodruff keys. You get runout due to the weight of the flywheel being off kilter and those forces push the flywheel off the flywheel gradually.
>>2877727Sorry I meant flywheel off the crankshaft. I'm tired.
>>2877354If it's breaking flywheel keys then it means the flywheel bolt isn't on tight enough. The key isn't supposed to actually stop the flywheel turning; it's more of a diagnostic tool to help you tell if the flywheel has moved from its intended position.Briggs and strratton is fucking garbage anyway, so just blast that flywheel nut as tight as you can get it with an impact. If something breaks, just shrug and get a honda clone.
Stop using candy to start it, Probably too late The keyway, like a cotter pin shouldnt be taking the force. Making one out of a file is a good suggestion
>>2878712>Making one out of a file is a good suggestionYes, it's great if you want to break a crankshaft.
