Sunday I'm mowing in areas no sane person would take a riding tractor when I hit a rock. I didn't hit it hard and I shut off the mower deck before I backed off. The rock was small and I barely nicked it. When I turned off the deck the whole mower shut down and won't start. It'll crank like a champ, but will not kick over.
So far this is what I have done and the darn thing still wont start:
-Pulled the fly wheel and the shear pin looks as new as the one I just bought at the John Deere store.
-Both spark plugs are sparking
-I have compression, but I haven't put a gauge on it to see how much.
-Replaced the fuel pump
-You can hear the fuel shut off thingy tick in the carburetor when you turn the ignition to the first notch.
-I put a few drops of gas in the air intake and the first cylinder fired, but didn't start the engine.
-The 25 amp fuze is fine
The only thing I have not done is replace the relay which I will probably do tomorrow.
I'm not an engine expert, but it seems to me I have covered all the bases. I'm thinking that since it died when the deck switch was shut off that I probably have a short or bad switch somewhere. I probably should down load the wiring schematics and start testing wires with a multi meter.
Oh, my riding tractor is an old Scotts L2048 (same thing as a John Deere L120) with a Briggs and Stratton 20 hp OHV motor.
Thanks for any advise.....
Also.....some mowers won't start if the oil's low. Just some guesses. Let us know what you find.
If no spark, quick and easy is to cycle through all the deck/blade engagement controls to make sure they are fully disengaged or the deck lifted. Seat switch is fully engaged, etc. Trans sometimes has to be in neutral, etc. (many have a reverse kill if deck is down and engaged and you back up)
Still no spark? These engines are grounded out to stop them, not like automotive and shut off power to the system. There will be a "kill" wire running to the engine. Disconnect it and try to start. My guess is it will fire up, if it does you will have to reconnect to shut it off. Then it's a matter of finding out which switch or wire is the issue. Don't overlook oil level switches, etc. especially if the equipment is on a slope.
Let us know what you finally wind up with!
Assuming it's a mechanical fuel pump, I'd disconnect the fuel line at the carb and stick the end of the line in a jar, then crank it over a few times. There should be healthy squirts of fuel. That will confirm fuel delivery. I've had brand new mechanical pumps that didn't work right out of the box.
If the pump checks out, that leaves air. Have you replaced the air filter lately? I've never had a dirty filter prevent an engine from starting, but stranger things have happened.
Beyond that, I'd start looking into any automatic shutoff features that are on the engine. My tractor's engine will shut down in neutral If I don't set the brake before standing from the seat, or if I try to stand with the tractor in gear. One time, the wire to the switch under the seat came loose, and the engine wouldn't start. Took me a while to hunt down that one.
Good luck,
Matt
Spark: Yes Compression: Yes New fuel pump: Yes (works off vacuum) New Relay: Yes Fuse: Good Fly wheel sheer pin: Good gas in carb air intake, did it fire: Yes
OK, so It's obvious I'm not getting fuel. I'm guessing my fuel shut off valve isn't working even though I can hear it click when I turn the ignition key. This sucker isn't cheap. I'll be shooting wires before I buy it.
Spark: Yes Compression: Yes New fuel pump: Yes (works off vacuum) New Relay: Yes Fuse: Good Fly wheel sheer pin: Good gas in carb air intake, did it fire: Yes
OK, so It's obvious I'm not getting fuel. I'm guessing my fuel shut off valve isn't working even though I can hear it click when I turn the ignition key. This sucker isn't cheap. I'll be shooting wires before I buy it.
Matt
No need to ask me how I know. ;-)
BB, no issues with the filter. It flows great.
Matt
Also...there is a chance you can take it out and clean it up and make it work again. I did that to mine for a while and it worked until the wire sheared off.
Here's a link to the owners manual, if you don't have one. May be of some help.
https://www.deere.com/common/docs/stellar/answer-center/Scotts-S2048-S2554.pdf
Itshot suggests a timing issue. I think the valves got out of adjustment on the hit.
You might want to look at youtube to find a good tutorial on adjusting the valves on that B&S twin. May be of value.
Other than what you've already done, I'm out of ideas.
Good luck
hoping its just fuel supply issue though
If you can hear/feel the fuel solenoid clicking it's likely working, not much to them but windings and a rod/needle and the valve seat hole is so big I've never seen one clogged. Have seen rubbish jam up the needle in the windings, but they won't move or "click"then.
Still need to check the spark to make sure it is steady and strong. If it were fuel if should start and run a few seconds with a shot of starting fluid (great diagnostic tool). Not just a random one time "pop" (which actually could be a timing issue like itshot and joey said. I've seen pushrods come off rockers on OHV engines. (Honda's, probably have 30 or 40 of em at the shop.... haven't worked on a Briggs engine in 10 or 12 years)
If good spark I'd take a look at the carb float bowl next, most will have some kind of a drain plug, some even a drain valve. Check for water. if you were Baja racing sometimes water that can accumulate at the bottom of the tank will slosh up into the pickup. Easy to check before diving into the carb. A big fan of checking things that are easy first. =D
1. Looking at your OP....I need to clarify....AFTER you hit the rock and BEFORE you shut off the deck PTO...was the engine running normally?
If NO....the engine did not run normally right AFTER rock contact, then we need to ask a few more questions about the engine.
If YES....the engine ran normally BEFORE you moved the deck PTO (shut off the blades), we need to take a closer look at your deck PTO switch system.
If I read your OP correctly....the engine shut down after you physically moved the deck PTO to stop the blades...yes??....no?? If the engine ran normally immediately after the rock hit....it doesn't sound like you have an engine internal, fuel or spark problem. If the rock hit did create an issue with one of those 3 things....logic would tell us the engine would not have run normally after the rock hit regardless of any further action you took after the rock hit.
Might have to start another thread about your F150 tranny.
AccMan's Link
Last night I cleaned up the carburetor and did a function check on the fuel shut off solenoid (works just fine). This morning I put it all back together and still nothing.
There is something up with the fuel pump. I don't know if there isn't enough vacuum to get it to work or maybe I just have another bad fuel pump.
Either way I'm pretty much done screwing around with it.
My F150 is at the local Ford dealer. It started slipping, the Transmission Fault warning came on, the Over Drive light started flashing, and it's leaking fluid out of the rubber plug on the bottom of the bell. Sucks, but it's a 2005 with 170K on it. I hate to say it, but this kinda stuff is to be expected.
Sorry to hear about your tranny....better now than the day before the opener.
Ok.....based on that confirmation.....me thinks if it was running great up to the point you pushed in the PTO switch....I see you're problem in one of the switches and NOT an engine problem.
I had a diagram last night of your lawn tractor's electrical system. Because it shut off only when you moved the PTO shut off, that would be a logical place to start.
It should have an electrical connection somewhere there as part of the engage/electrical safety system. Check the electrical connection and make sure it is properly connected, not loose or broken wires....something obvious. If nothing observed, remove it, check for corrosion, dirt, funk and spray it out with some WD-40 and reconnect. Try to start. It's possible the switch itself is bad. In that case you'll need to do some switch testing if you're comfortable with it.
Check your seat safety switch/wires the same way as above.
Check the brake/clutch/neutral switches/wires the same way as above.
Confirm oil sensor connection/wires as above. (and oil level)
Confirm ALL fuse links are good and not blown....use a meter.
Check the key switch and wires as above.
Hopefully it's one of those switches in the electrical safety system. If not, we can go from there.
I never did check all the wires. I'll take a look at these tonight.
So now we're down to air or spark.
Only way timing can get off on those engines if the keyway on the shaft is broke. He verified it's fine.
Getting spark on both cyclinders? Verify that.
Air cleaner clean? Easy enough to look at. Remove and clean off.
Couple shots of starter fluid in the carb should fire her up. At least for a few seconds.
You could try cranking with the gas cap off. See what she does. Vapor lock somewhere?
Only other thing I can think of is when you hit the rock, pushrods may have crimped slightly throwing the valve positioning off.
Sorry about your truck. Alwys a good idea to periodically check trans fluid level, color, and smell. That milage on that year truck shoul;d not have much to do with engine or trans issues if maintained.
Can't help you out more on that end. Fixing trans problems is outta my wheelhouse.
However.....not to get tunnel vision....I did some more looking online and quiet a few JD folks had the fuel tank vent cap clogged. He could unscrew the cap and try to start it. If it starts then clean out the small hole on the cap.
I had a spark plug a couple of years ago on a mower that looked like it was sparking good. I replaced the plug anyway and that solved the problem. He said one cylinder fired when gas was put in. New plugs would be worth a try. At the same time I'd check the compression with a gauge.
Fuel is not coming out of the fuel pump.
I cant get it to start with starter fluid.
Pouring a few drops of gas down the air intake has occasionally worked.
Well, my tranny repair will cost me 2500 or so. Its ok, its better than the 4k the Ford dealer 2anted to charge me.....eek
Find a kid or spouse to hold the plug wire terminal when cranking..... (just kidding..... kinda.... my lil brother still brings this stuff up from like 45 years ago....) Cheap spark tester from the auto parts store. Great tools. Last a lifetime.
Not gonna help the tranny though..... sorry... (sigh... I remember when "tranny" had pretty much only one meaning.....)
DD, I'm wondering the same thing.
DD, I'm wondering the same thing.
Awesome!
Still working at it.
I need to start a go fund me account to pay for it... LOL
If you confirmed all the switches are good.....if it is a vacuum fuel pump.....do compression check on both cylinders with a gauge. It should be over 100 from the Youtubes I looked at. The one vid I looked at of a JD had low compression on one cylinder. He pulled off the valve cover and turned the engine over paying attention to the valves and push rods. In his case, the push rods were bent. One valve wasn't moving. This was his cause for the low compression which in turn would mean low vacuum which wouldn't drive the pump. Also try squirting starting fluid in both cylinders one at a time. Try to start it and see if it only tries to start on one cylinder. That would suggest the other cylinder/valve train could be the problem.
I bought a compression tester.... nothing, didnt move the needle. I stuck an arrow in each piston and they arent moving..... EEEEK
The plot thickens.....
Matt
I'm not familiar with your specific engine, but most starters have a bendix drive that engages and disengages the starter gear with the flywheel. It that bendix is malfunctioning or broke, the starter will spin but not engage.
Do you have a diagram of your engine that shows all the major components?
Matt
You can remove the starter and hot wire it to confirm the bendix is working. Youtube it, there should be several how-to examples.
Good luck, brother, and keep us posted
Matt
I was checking out your engine here:
https://www.green-parts-direct.com/john-deere-parts-diagrams/john-deere-l120-lawn-tractor-with-48-in-mower-deck-material-collection-system-pc9290-crankshaft-piston-engine-gu20279-gu20453/AD-4275-175293-130448
You can scroll thru the smaller windows at the top of the page to get to diagrams of every part. It doesn't appear to be a very complicated engine to tear down and repair, and parts seem relatively cheap. That may not be your thing, though....
Sorry for your troubles. If I were nearby, I'd offer to come over and help.
Matt
Terry
Good call. That shaft key that holds the crank gear to the crank shaft may be sheared. It would certainly be worth checking before springing for a new engine.
If it were mine, it would already be in pieces all over my garage floor. I love tinkering with engines.
Matt
I should have the truck back this week.
The bottom line is, if the flywheel is turning, but the pistons aren't moving, there's a disconnect from the flywheel to the crankshaft, or from the crankshaft to the pistons.
Thats really the only the two options, IMO.
Matt.
If that flywheel nut wasn't tight enough the starter alone can shear the flywheel and with the tapered shaft and all it could (cross your fingers) just be spinning on the crankshaft. If not..... something pretty serious. Either broken crank or (very unlikely) both connecting rods cut loose at the same time. (if you checked both cylinders and both doing the same thing.)
If the crank or conn rods.... I'd look to a new engine unless this was a very low hour engine. Parts alone likely a third of the cost of an engine.
Good luck, I'm rooting for a loose flywheel.....
About 4 hp. ;-)
Matt
I just got off the phone with a local small engine mechanic. He said I most likely threw a rod and that it'll be cheaper to just replace the engine. So I'll be ordering a new motor. I'd buy a new tractor, but I need a garden tractor (terrain around my house will wear out a riding mower fast) and its a matter of principal..... LOL
To be honest, this is most likely my fault. I haven't checked the oil in a few years (which means it hasn't been changed either). The oil level was low, but not empty. This happened while I was on an incline. Maybe there wasn't enough oil to keep everything lubed and she gave way..
Man, this sucks, My daughters car got hit in Walmart and the driver left the scene(insurance covers that one), I blow my engine on my riding mower, AND my truck tranny goes out all within 10 days..... LOL
Good thing I'm made of money and can pay for all this...... LOL
A connecting rod for that engine is only $51. Another $10-20 for gaskets, maybe.
Just saying.....
Matt
At any rate, I hope you get up and mowing soon. I'm truly sorry for your string of bad luck.
Matt
We agree. A broken rod usually causes major carnage inside the block. Cranking the engine with a broken rod usually causes a loud clatter with all those pieces flying around inside.
I've been thinking a sheared shaft key ever since T-Flight discovered the flywheel was turning while cranking, but the pistons weren't moving,
Matt
Ill prob tear it apart just to see whats up. I may even rebuild it later. Im thinking of building a hover craft and could use the motor for that.
On a good note. I started clearing the food plot dite with my lawn mower. I need to cut a few trees fown but i need a new chain. Ill pick one up tomorrow.
IMO good call on the new/used engine. Although a used ebay engine my be a roll of the dice...... When I was a kid I used to fix up engines like the one you blew up and sell em to folks. =D
I never sold one that didn't run well though.......
With each new bit of info the picture gets clearer.
If the crank didn't turn when you pushed the pistons down then it's definitely broken connecting rods. The loud clanks you heard was the broken half of the rods, that are still connected to the crank, banging against the other broken halves that are connected to the piston. It probably shoved the pistons back up in the bore where they remained, therefore the noise went away.
Sounds like a good score on the used engine.
Matt
Replaced the motor today. It runs GREAT!
