Wont Start

Kenneth in Texas · Jul 28, 2016

LTX 1046, Briggs & Straton engine. Was running fine, then just shut off like you turned the key to off.

Now will crank, have headlights when you turn the key on but just wont start. Have gas going thru filter and up to carb. What do I look for next?

Maxify55 · Jul 28, 2016

When you turn the key and crank it, do you get spark to the plug?

Pull the plug and reattach the wire.

Crank the starter and watch to see if you are getting spark to the engine.

Either plug will do.

LTX 1046 shows a twin cylinder Kohler but you say a briggs engine is installed?

Kenneth in Texas · Jul 28, 2016

yes have spark at plugs, have gas coming out of fuel filter if line is disconnected

Kenneth in Texas · Jul 28, 2016

B&S professional grade, 23hp

Cub cadet manual says LTX 1046VT

ultrarunner · Jul 28, 2016

My quick and dirty diagnostic tool for service calls was a can of starting fluid...

If the motor cranked but would not start I would give it a short shot at the intake and if it fired I reasonably knew the ignition was OK.

If not, I would pull a plug and check condition and look for spark.

Bob_Bainbridge · Jul 29, 2016

I agree, starting fluid is the way to go. You may have gas coming out of the filter but not the carb The float could be stuck in the up position. If it starts with the starting fluid you have a carb problem. The other 2 elements needed are compression and timing but those two will usually result in backfiring or at least an attempt to start.

Bob B.

rcbe · Jul 29, 2016

OP/Bob... lose the starting fluid! Ether will blow a small air cooled engine. Use rattlecan carb cleaner instead.

OP - also chk to see that the afterfire solenoid at the carb bottom is getting 12vdc and actuating/staying open - if not, fuel will be shut off to carb.

Kenneth in Texas · Jul 29, 2016

rcbe said:
OP/Bob... lose the starting fluid! Ether will blow a small air cooled engine. Use rattlecan carb cleaner instead.

OP - also chk to see that the afterfire solenoid at the carb bottom is getting 12vdc and actuating/staying open - if not, fuel will be shut off to carb.

im getting 11.73v at the plug in to the solenoid, same as the battery, now how can i be sure its actuating?

Bob_Bainbridge · Jul 30, 2016

rcbe said:
OP/Bob... lose the starting fluid! Ether will blow a small air cooled engine. Use rattlecan carb cleaner instead.

OP - also chk to see that the afterfire solenoid at the carb bottom is getting 12vdc and actuating/staying open - if not, fuel will be shut off to carb.

I'm not familiar with the carb cleaner but have regularly used starting fluid on lawn mowers, my Harley, and cars for 65 years and haven't blown one yet. I even used it on my 1980 GM Pontiac diesel, which had a decal on the air cleaner saying "DON'T USE STARTING FLUID". It made the difference between starting or not starting in sub 20 degree weather when I forgot to plug the block heater in. It lived for 145,000 miles which was good for a poorly designed bad engine. YMMV

Bob B.

ultrarunner · Jul 30, 2016

In the shop on carb vehicles we have used a whiff of starting fluid as a Diagnostic tool going back to when I was a kid...

I also have a lot of cars in storage... some 50+ vehicles... I find a little starting fluid easier to use than a dropper of gasoline...

My old Deere 350C even has a starting fluid port for subzero temps.

JRobyn · Jul 30, 2016

Kenneth in Texas said:
im getting 11.73v at the plug in to the solenoid, same as the battery, now how can i be sure its actuating?

To be certain, you need to pull it off and connect it to some temporary 12v supply (the battery, a battery charger, a 12v wall wart) and confirm that it's moving. A quick test that sometimes works is to disconnect the electrical plug from it, then turn on the ignition, then listen carefully and feel it while you plug and unplug it a few times. There should be an audible "click" and a slight "bump" that you can feel. *Note* You may need to have a helper sit in the seat or bypass the "operator presence" switch while doing this to actually make the ignition circuits active.

oldpilgrim · Jul 30, 2016

a bad safety switch somewhere? Backup lockout safety switch?

ch1ch2 · Jul 30, 2016

oldpilgrim said:
a bad safety switch somewhere? Backup lockout safety switch?

He said he has spark.
That only leaves fuel.

oldpilgrim · Jul 30, 2016

ah, read too fast and missed the spark post.

oldpilgrim · Jul 30, 2016

i have an ltx1046 and it has a kohler engine, with a very small fuel pump. Does the BS have one? if so pull the output hose off and turn the engine over.

Kenneth in Texas · Jul 31, 2016

**All the safety switches kill this mower completely, wont crank if its a saftey switch.
**the carb solenoid clicks and i can feel a bump inside when key is turned on.
**ah, a fuel pump? On a small B&S 23 hp v-twin? Dont know will have to see, what will it look like?

EDIT: whoa looks like it does have a fuel pump, didnt know, will have to disconnect the hose running to the carb and give it a crank tomorrow. I feel stupid now

never owned a rider that had one but then again never had a CC with this large of engine on it. Sure hope thats what it was, wife was driving it when it stopped, she said it was just like turning the key off the way it stopped, no backfire, no sputter, just a clean engine stop.

rcbe · Jul 31, 2016

ken in tex - with yer wife in tractor seat - remove carb air cleaner - have wife to try to start engine normally - spray several shots of rattlecan carb cleaner directly into carb throat. If engine pops or tries to start, you have a fuel delivery problem. If not, an ignition or mechanical prob.
fuel delivery prob: remove fuel line at carb. using catch can, carnk engine, observe fuel flow stream from line. If good, pull/clean/rebuild carb. If no stream, find prob and fix. otw, proceed:
you already say you have good ign. other thing to chk given your comments is possible - sheared flywheel key. Wife may have hit something with running blades and shock may have damaged key. To check/repair, you will need engine service manual, torque wrench, etc. ie., a bit more than a pair of pliers and a screwdriver. plan accordingly or google this site for more detail.

Kenneth in Texas · Jul 31, 2016

SUCCESS! The fuel pump is not pumping any fuel. Thank you all for your comments and suggestions. Ordered one online today and hope to be back up and running in a few days.