Mower rebuild


Old 06-16-07, 09:15 PM
Thread Starter
Join Date: Jun 2007
Posts: 3
Mower rebuild

briggs and stratton
family ybsxs.1901vc 274466
stamped into the body near the carby24990

Old Problem - inlet valve stuck open, fixed with WD40 and a hammer
New Problem - valve timing gear slipped out before i had the chance to draw the placement, 60 or so different combinations for that gear plus the gear that sits on top of it ( which i wouldn't have a clue even what it is for )

the gear is plastic of all things and has 2 cams on it for the inlet and exaust valves, 2 markings as far as i can see, one groove which doesn't make sence when lined up with the groove on the drive shaft and a picture of a round clock which i dont think is used for timing. Does anyone have an extract from an overhaul manual or knowlage of where the timing gear and the placement of the otherone ( which sits at a right angle ontop of the timing gear. )

Any help would be appreciated, especially from someone who has the manual or alot of experience on the subject.

PS Please do not post in reply "Its not worth it, get another one, dont bother with it, i can sell you one cheap" as that does not help my situation
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Old 06-17-07, 08:59 AM
Join Date: Mar 2007
Location: Southern Wisconsin
Posts: 354
The timing mark on the cam shaft gear is the groove or notch. This lines up with the dot on the crank shaft gear. The other marks or circles you are seeing are mould release spots from the manufacturing process.
Old 06-17-07, 04:21 PM
Thread Starter
Join Date: Jun 2007
Posts: 3
one down, how many to go?

valve timing i believe i have fixed, there was a dot that i didn't see on the drive gear that lined up and now the valve timing makes sence.

Still will not fire though unless it is full of "start ya *******". The third gear i didn't see anything that made any difference in timing though i will try to pull it apart again.

Other than that i think that i can try a direct gas injection if i make up an air cleaner \ filter with an LPG connection and run it from a gas bottle. I believe this will bypas the need for the third gear but i am unsure what problems that i will run into if i do it this way.

At the moment as i think the third gear is ok i think the problem may lie with the carby, perhaps i missed something when i cleaned it or i didn't put it back together properly.

Any suggestions on the gas injection system would be appreciated.
Old 06-17-07, 04:25 PM
Thread Starter
Join Date: Jun 2007
Posts: 3

thankyou for your reply, i ended up finding that shortly after posting this, there are still a few issues, any clue about the third gear? it will be a day or 2 before i pull it apart again or try the gas injection so i will wait for posts this time.
Old 06-17-07, 04:48 PM
puey61's Avatar
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
The numbers you posted are only emissions reference numbers not engine identification numbers. Since I have no idea what you have for an engine most flat head engines have the model, type and code numbers either stamped directly into the flywheel shroud or stamped into a plate that is in turn riveted to the flywheel shroud and most overhead valve engines will have the numbers stamped into the/a rocker (valve) cover. Find these numbers and post back.

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