Briggs 18hp twin runs backwards!

[zman007007]

I don't believe any of this bull. new armature in what the starter? If it was, it meant the starter was turning backwards which in that case would never have engaged the flywheel, unless also the starter gear was upside down. Even then a 4 stroke I would find hard to believe would run in reverse rotation. I believe we are having some serious B/S here. ZMAN :confused2:

 

[hawkeye08]

I don't believe any of this bull. new armature in what the starter? If it was, it meant the starter was turning backwards which in that case would never have engaged the flywheel, unless also the starter gear was upside down. Even then a 4 stroke I would find hard to believe would run in reverse rotation. I believe we are having some serious B/S here. ZMAN :confused2:

BS detector went off when I first read the title. Agree.

 

[zman007007]

I know the 2 stroke engines on my old Harley Davidson golf cart engines run backwards and forward. Thats why you have to let the engine die completely, before you change it from forward to reverse. zman AKA Pete:thumbsup:

 

[SPYDERLK]

I've got 18hp twin briggs that runs backwards. It ran backwards when I first started it up. I adjusted the ignition gap and it ran normal for a little while. Then it switched to backwards again and has been backwards ever since.

Things I did before starting it up: (1) new stator, (2) full carb clean (3) new flywheel key, (4) new spark plugs, (5) new oil.

I am having trouble torquing down the flywheel nut. I've heard it needs 145 ft-lbs. (is this right?) I can't lock the engine to get the torque on it. I already bent a belt pulley when I was using a belt and vice-grips to stop the engine so I could tighten it up. Any advice about how to lock this engine so I can tighten that flywheel nut?

I've been playing with the ignition gap but I can't get it to run normal again. Does anyone know why this motor runs backwards and how I can fix this?

Thanks,
Backman

If it ran Ok forward and you havnt taken it apart and recammed it, it wont run backward well ... or at all if its a single. Running backward would imply intake thru the muffler followed directly by exhaust thru the carb. Im assuming its a 2 cyl with a single carb. Depending on how the cyls are timed wrt one another I guess exhaust thru the carb could possibbly force gas into the other cyls backward exhaust stroke during valve overlap. Could make it possible to run -- but no power. By rights it should be a fire.
larry

 

[Skyco]

I'm like Paul Harvey- I want the rest of the story
Was this a replacement engine?
Was it used?
The statement that it runs clockwise looking down on it seems to jive with the B&S vertical shaft engine on my Snapper, it also runs that way. The online manual for this engine also shows it running clockwise.
Is it now running counterclockwise after the starter work/armature/pinion?

 

[zman007007]

#6A. Had too many Bud lights and now my eyes are spinning backwards. lol zman :confused2:

 

[bjustice]

I have a B&S engine and mower combination almost identical to the one in question--I have also had the complete mower run backwards when it should run forward. It is due to the belts being installed wrong--this is a very easy thing to do, and not at all obvious. It only requires a half turn of the belt (a half-turn is required for installation) in the wrong direction and the machine will indeed run backwards--but the engine will NOT run backwards. remove the belt and make a half-turn in the other direction and everything will be fine.

 

[SPYDERLK]

I have a B&S engine and mower combination almost identical to the one in question--I have also had the complete mower run backwards when it should run forward. It is due to the belts being installed wrong--this is a very easy thing to do, and not at all obvious. It only requires a half turn of the belt (a half-turn is required for installation) in the wrong direction and the machine will indeed run backwards--but the engine will NOT run backwards. remove the belt and make a half-turn in the other direction and everything will be fine.

... This doesnt explain the tractor running backward. ... A half twist of the belt in either direction results in the same reversal of the driven pulley.
larry

 

[The Haymaker]

I have a B&S engine and mower combination almost identical to the one in question--I have also had the complete mower run backwards when it should run forward. It is due to the belts being installed wrong--this is a very easy thing to do, and not at all obvious. It only requires a half turn of the belt (a half-turn is required for installation) in the wrong direction and the machine will indeed run backwards--but the engine will NOT run backwards. remove the belt and make a half-turn in the other direction and everything will be fine.

As I mentioned many posts ago..... Number one rule in troubleshooting machines. Look at the obvious, or bring the Bovine Fuel Cell Byproduct Removal Device..... A shovel, in laymans terms.

And it's not even April yet.

 

[bjustice]

As I mentioned many posts ago..... Number one rule in troubleshooting machines. Look at the obvious, or bring the Bovine Fuel Cell Byproduct Removal Device..... A shovel, in laymans terms.

And it's not even April yet.

Good rule--I agree.

Also if the belt exit side of the driven pulley is switched from the "normal" loop configuration to the "crossed loop" configuration, it will be driving the driven pulley in the opposite rotation. That is what happened here. I must have explained it badly in my earlier post. My engine also runs clockwise--since 1986. Engine is Model 4220707 type 0179-01.