Crankshaft bolts/nuts on various models

[ILENGINE]

The fuel solenoid requires a minimum of 9v to operate, and the regulator/rectifier requires 10v to close the internal switch to allow power to reach the battery. Some engines are set up for the regulator to output power without a battery for various operations( wide area mower) so it is doable, which would also power the fuel solenoid.

You can get some mowers to run without a battery, but if you momentarily get the voltage to drop below that magic number, say kicking in the pto, the charge system will open the micro switch, and kill output from the regulator, and therefore shut down the engine because no power is reaching the solenoid.

The fuel solenoid job is to help prevent the BANG it will no stop a carb from overflowing and flooding the engine and crankcase with gas. Now there are others systems out there that shut off the fuel flow to the carb Some are electric, some work on engine cranking vacuum pulses.

 

[turbofiat124]

The fuel solenoid requires a minimum of 9v to operate, and the regulator/rectifier requires 10v to close the internal switch to allow power to reach the battery. Some engines are set up for the regulator to output power without a battery for various operations( wide area mower) so it is doable, which would also power the fuel solenoid.

You can get some mowers to run without a battery, but if you momentarily get the voltage to drop below that magic number, say kicking in the pto, the charge system will open the micro switch, and kill output from the regulator, and therefore shut down the engine because no power is reaching the solenoid.

The fuel solenoid job is to help prevent the BANG it will no stop a carb from overflowing and flooding the engine and crankcase with gas. Now there are others systems out there that shut off the fuel flow to the carb Some are electric, some work on engine cranking vacuum pulses.

How come the older model lawnmowers don't have this solenoid mounted in the fuel bowl and they didn't backfire? I'm not disputing you on it's purpose, just trying to figure how why they started putting these on carburetors at some time or another?

I've rebuilt some Weber carbs that had something similar. It's purpose was to prevent dieseling after shutting the engine off when unleaded gas was horrible back in the 80s. I've heard these solenoid valves can go back and leave you stranded so I just cut the tip off mine. It has to have power before it will open. I've never had any issues with dieseling. My father's truck use to "diesel" back in the 1980s. Then for some reason it stopped.

My Trabant had a petcock valve coming of the dash. I ended up installing a fuel solenoid shut off valve to I wouldn't have to remember to shut/open the valve. The brass thing. Ignore that Mr. Gasket filter.

 

[RDA.Lawns]

In part to get emission compliance they redesigned the fuel supply systems and carbs. That required the fuel shut off solenoid.

 

[ILENGINE]

Part of the afterfire could be due to engines running leaner to meet emissions standards therefore run hotter. Lawnmower engines will actually make the muffler glow on riders and pushmowers more so than years ago. Use to have a 71 CC 106 that would afterfire if your didn't idle it down for a few seconds before turning off the key.

People may of just become less tolerate of the BANG and wanted it gone.

 

[bertsmobile1]

It is EPA regulations to prevent fuel being sucked into the carb & blown out unburned in the dozen or so revolutions between when you turn off the the engine & it stops spinning.
Hard to believe I know just think of Mr Pencildick from the original Ghostbusters.

AS previously stated mufflers run red not to after burn any unburned fuel during use then when you turn it off, air enters the muffler which has fuel vapours in there and a red hot ignition source so when the air:fuel ratio becomes correct for burning at atmospheric pressure it goes bang

 

[turbofiat124]

It is EPA regulations to prevent fuel being sucked into the carb & blown out unburned in the dozen or so revolutions between when you turn off the the engine & it stops spinning.
Hard to believe I know just think of Mr Pencildick from the original Ghostbusters.

AS previously stated mufflers run red not to after burn any unburned fuel during use then when you turn it off, air enters the muffler which has fuel vapours in there and a red hot ignition source so when the air:fuel ratio becomes correct for burning at atmospheric pressure it goes bang

Thanks guys for the explanation.

 

[Boobala]

First of all, can someone tell me why B&S is no longer installing recoil starters on lawnmowers? At least on 17.5 HP and up models. This is very handy when you discover that the battery has bit the dust after the winter and you really need to mow your yard that particular day before going back to work the following day or you're like me and you're too cheap (or frustrated) to buy a new battery every other year.

When did Briggs and Stratton went from using nuts to bolts on the crankshaft/flywheel?

Reason I ask is I have this nutty idea to made a rope starter for one of my lawnmowers. Most likely my MTD 17.5 B&S engine. I also have a 21 hp B&S Husqvarna. I'd like to do both.

I have a 14hp B&S circa 2000 that threw a rod through the block. It looks like the rod bearing nuts were not properly torqued or had Locktite from the factory and vibrated loose which sent the rod through the block. The engine was less than 5 years old.

This engine is on a shelf in my storage building and I'm going to have to move some stuff to get to it and pull the cooling shroud off to find out.

The plan is to:

1) Drill a hole through the side of a socket and the crankshaft bolt for a roll pin or cotter pin.
2) Up through the socket will be a 1/2" carriage bolt threads facing upwards. Maybe a few flat washers to take up any slack in the depth of the socket.
3) Use a pulley that uses a square keystock to keep from spinning
4) Grind a slot in the end of the carriage bolt for the keystock.
5) Cut a groove at an angle for the knot on the end of a rope.

This winter I pulled my batteries off my mowers and hooked them to trickle chargers. Hoping I can get more than 1 to 2 years out of these horribly cheap lawnmower batteries everybody sells.

As long as I have the strength and ability to pull start a lawnmower engine, I'd just soon do that as to keep spending money on these junk batteries.

I think my Interstate battery made it one season. The Husky battery from Lowes (I think) made it 2 years before it bit the dust.

The battery on that same Snapper went bad after a year and I just pulled started it for 10 years until I sold it.

I think you're thinking SOMETHING along these lines ... ???

......

 

[turbofiat124]

I think you're thinking SOMETHING along these lines ... ???

......View attachment 31885

Yeah I seen a YouTube video where someone did that. Quite clever if you ask me.

Both of my engines looks a bit different than this particular model so I wasn't sure if I could do the same until I remove the cooling shroud to see if there is a lip on the piece that goes under the crankshaft bolt to bolt a pulley to.

I've got an old Snapper deck in my scrap metal pile I'm going to scavenge the pulleys from and give it a shot.

I'm definitely giving this a shot. I'm tired of playing musical batteries between riding mowers and paying $50 for a battery than only lasts 1 or 2 years.