I've also disconnected the brake wiring, etc, to the coil as to avoid those obstacles up front.Hello,
I have a lawn boy #10685 self propelled mower, with a Tecumseh LV195SE engine, spec 362044D, that will not turn over. There is spark and I see that the primer is operating as it is bringing fuel into the carb. I've replaced the plug, coil, oil and other non related items. I've tried to start it with "starting fluid" and that doesn't do a thing. Could it be low compression? Thanks for your help and idea's.
Thanks, I did that. had no spark and replaced the coil and plug as there was no spark. Now I have spark but will not turn over.With an engine that old and not running, the first thing I would do is to remove the carb and rebuild it with a new float needle and seat.
Thank you for the suggestion.Thanks, I did that. had no spark and replaced the coil and plug as there was no spark. Now I have spark but will not turn over.
Well, that is possible but would I still get spark to the plug if the coil were upside down? Would low compression play a part in my challenge?Couldn't of installed the new coil upside down possibly. That can also cause starting issues in some cases.
I'll check the idle jet one more time, thanks. How do I rest the float level slightly rich? I'm a novice, thanks.When you cleaned the carb, did you remove the idle jet, under the black plastic cap, and make sure it was open in both directions? Also, did you replace the float needle and seat, part 631021 and rest the float level slightly rich?
I'll try later this week, thanks.Set the float so it is slightly lower on the side opposite the float pin.
Got it, that's what I was thinking, thanks.I should have added that’s when the carb is tipped upside down.
Thanks. I've taken the flywheel off and the key/slot are intact and inline. Cannot get it to turn over getting both spark and fuel. My only thoughts are its very low compression. Would that be a plausible theory? Thanks.I am not a pro so take my thoughts with that in mind. You may indeed have a carb problem, but if that were your only problem then the engine would have started and died when you had spark and used the starter fluid. Only two other causes for a no start when you have fuel and spark. Compression is one and ignition timing is the other. As other more experienced folks have noted, valves can cause low compression. Cylinder wear will do the same. I kinda suspect ignition timing coupled with low compression. I know you said the flywheel key was intact, but sometimes they don’t shear and it is hard to see if they moved by just looking on top. I would take the flywheel off and see if the slots align. Even if I’m wrong, that would get you closer to solving the mystery by completely eliminating timing as an issue. Not so great compression together with slightly altered timing may result in a no start condition.
That was my thought. 45 psi is half of what some state is the minimum for an engine like this. The range stated is 90 psi to 120 psi.Once you eliminate fuel, spark and timing, the only cause for nonstarting that I can think of is low or no compression.
If compression reading is accurate, then 45 psi is too low for engine to start and run. You need about 60-70 psi minimum for most 4-stroke engines to start and run. The problem is that there is often a compression release involved and it throws off reading. The compression tester may be off on accuracy. Is the 90-120 psi spec in general, or specifically for this engine? In general, 120 psi is what a healthy 4-stroke will read.That was my thought. 45 psi is half of what some state is the minimum for an engine like this. The range stated is 90 psi to 120 psi.
Thank you. I'm taking head off, cleaning carbon from the valves and piston head. Looking for other problematic opportunities. Thanks for everyone's help here.If compression reading is accurate, then 45 psi is too low for engine to start and run. You need about 60-70 psi minimum for most 4-stroke engines to start and run. The problem is that there is often a compression release involved and it throws off reading. The compression tester may be off on accuracy. Is the 90-120 psi spec in general, or specifically for this engine? In general, 120 psi is what a healthy 4-stroke will read.
In every engine manual out there as a periodic maintenance item. Good job. Could cause low compression. Chunk of carbon holding a valve open. Valve seat out of the block from over heating. Compression release little too active, is that even a thing? Failing compression release. Poor valve sealing. Rings stuck to the piston. Gouged up cyl bore.taking head off, cleaning carbon from the valves and piston head.
Thank you.This manual should help you out. https://www.mymowerparts.com/pdf/Te...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf
Try changing spark plug.With an engine that old and not running, the first thing I would do is to remove the carb and rebuild it with a new float needle and seat.
Thanks for your precise diagnostic procedure. I did change to the plug, drained and changed gas, changed to oil, disconnected all wiring and brake cables to the coil so these wouldn't be an issue. I had spark and fuel. I believe the plug was wet enough when I'd checked it and I did test the plug spark on the engine head. I hadn't placed my finger over the plug hole but should've. I have a big oil leak it appears at the engine flange mount gasket....which is a big deal to me.You've covered a couple of things and it is usually fuel but here's the best diagnostic procedure I have found.
When tomorrow comes in with a no start condition, the first thing you should do is physically look at the safety bail engine stop cable to make sure it is actually pulling when you pull the cable because sometimes they come in and the cable has popped out of the handle. Lol
Then, you should pull the rope and see if it feels normal.
It should have the hard spot of compression unless a rod is snapped or there's a massive valve problem and it should not pop or backfire after three or four pulls or try to pull the rope out of your hand -which would tell you it's a partially sheared flywheel key.
So after this if it all feels normal I pop off the air filter and give it a squirt of carburetor cleaner in there and then pull it three or four more times to see if it'll run for a couple of seconds.
Normally it does so you're diagnostic procedure is over and you just have to clean up the carburetor and you're good to go.
Yours seems to be one that's not in the 80% and does not have a fuel problem.
Now the next place I go to is the spark plug.
Don't get me wrong, I'm not considering this plug being bad but I take the plug out
Then I place it back in the coil wire and hold it against the block and pull the rope a couple more times and look for a nice bright strong spark.
Also make sure it's at the right location between the tip of the center electrode and the ground as I've had several that are sparking out to the side of the threads or down along the insulator.
While you're doing this you can also do the next check which is put your thumb or finger in the spark plug hole and make sure it blows your finger out and you really can't keep the air inside.
If it does this you know it has enough compression.
Now while you're doing this which is easier if you have someone else pull the rope so you can get a nice full pull, you want it to go blow blow blow blow.
It should be very rhythmic and consistent.
He should never go blow blow space space space blow and it should never try to suck your finger into the hole.
If it sucks your finger in you have an intake valve probably not opening.
If the pattern is not consistent then you could have a valve issue or even a camshaft issue.
At this point you usually know something is up from these tests and you can go about fixing it.
If everything checks out up until now and even if it wasn't trying to pull the rope out of your hand you should now check the flywheel key to make sure it is not partially sheared.
Then, or maybe right before you check the key, you should try a known good plug because sometimes a plug that Sparks great outside just won't have much oomph under compression.
You will likely still see the original cross hatch in the engine and they probably won't be any scores at all but if you see a few vertical ones as long as there's not five or six around the bore and as long as they're just fairly small and you can't really catch your fingernail in them too much it's not really a concern.Thanks for your precise diagnostic procedure. I did change to the plug, drained and changed gas, changed to oil, disconnected all wiring and brake cables to the coil so these wouldn't be an issue. I had spark and fuel. I believe the plug was wet enough when I'd checked it and I did test the plug spark on the engine head. I hadn't placed my finger over the plug hole but should've. I have a big oil leak it appears at the engine flange mount gasket....which is a big deal to me.
I now have the engine off the deck and I'm cleaning the exterior so I can see things better and keep the area as clean as possible once I separate the engine block and base. I hesitate doing this but the gasket has to be changed to stop the leak. As long as I'm going this far I thought I'd look at the internal components. My concern is the cylinder bore and wondering what type of scoring is tolerable?
More to come as I move forward and thanks to you all for your help and support.
Scoring on the piston, rings, and cylinder on a four stroke:You will likely still see the original cross hatch in the engine and they probably won't be any scores at all but if you see a few vertical ones as long as there's not five or six around the bore and as long as they're just fairly small and you can't really catch your fingernail in them too much it's not really a concern.
For that base gasket or some gasket or what do they call it, they usually don't leak a lot there but I have found tricks to fix them.
I had several of the Kohler XT engines come in that were leaking down there.
You tilt The Mower and whichever side or angle you need to so there's no more oil puddling on the inside there and then blast it with carb cleaner three or four times and with compressed air to get all the oil off the area... Then you can take some of the good RTV like the ultra stuff that's more oil resistant and spirit and push it right into the gasket area.
Some of these are so hidden that I had to use it on the tip of a screwdriver but as long as you push it in there with a wiping motion and then I usually go back and dab some more on top but still pushing it on top and then leveling it out to the sides.
I think I've done three of the colors so far maybe four and not have one of them leaked afterwards
I left them up in the air like that to dry overnight and then set them back down and started them.
If it works it works.
Thank you.You will likely still see the original cross hatch in the engine and they probably won't be any scores at all but if you see a few vertical ones as long as there's not five or six around the bore and as long as they're just fairly small and you can't really catch your fingernail in them too much it's not really a concern.
For that base gasket or some gasket or what do they call it, they usually don't leak a lot there but I have found tricks to fix them.
I had several of the Kohler XT engines come in that were leaking down there.
You tilt The Mower and whichever side or angle you need to so there's no more oil puddling on the inside there and then blast it with carb cleaner three or four times and with compressed air to get all the oil off the area... Then you can take some of the good RTV like the ultra stuff that's more oil resistant and spirit and push it right into the gasket area.
Some of these are so hidden that I had to use it on the tip of a screwdriver but as long as you push it in there with a wiping motion and then I usually go back and dab some more on top but still pushing it on top and then leveling it out to the sides.
I think I've done three of the colors so far maybe four and not have one of them leaked afterwards
I left them up in the air like that to dry overnight and then set them back down and started them.
If it works it works.
I have the engine block and base separated. I'm going to clean internally and look at the bore, piston, etc. If I can catch a fingernail on vertical internal bore marks is there any hope? Do I disconnect the connecting rod, piston and review the rings and how they appear? Not sure how far to really take the bore score marks and rings. Thanks.Scoring on the piston, rings, and cylinder on a four stroke:
Being able to tell if the compression is too low due to excessive scoring takes experience. There is no set “go, no go level.” You can only see the condition of cylinder, without removing the head and taking the piston off of the connecting rod. Therefore it is the cylinder you are focusing on. Need an endoscope to see into the spark plug hole. Therefore without the proper tools and experience, it is difficult to look for scoring.
Heck ya', first troubleshooting thing on the list for all mowers. The ol' spark plug trick.Have you removed the spark plug and replaced it with a new one
Or use a cheap USB bore scope. Tug on the rope to lower the piston in the bore. Some you might not see the bore maybe. Still cheap to pull the head. Probably needs de-carboning of the cylinder/s anyway.You are way over thinking this. Don’t even need to remove the engine from the equipment. To check for scoring all you need to do is remove the head and look at the cylinder. A good mechanic can quickly ( in 15 seconds ) identify a cylinder which has been damaged. You only need to be able to see the top 1/3 of the cylinder. Have you even looked at the manual I posted?
That level of compression will make things very very difficult to get it to start. the speed of piston moment makes a difference in firinng time compression. In our shop, we do a slow pull and feel the compression. If little resistance, no need to go farther. It's dead.Thank you. Key is intact. I'd taken a compression measurement and it is at approximately 45 psi. I read that it should be between 90 and 120 psi.
Why not? More tools the better. If you don't like tools then more for me.A bore scope??? Why? The price of a head gasket is far cheaper and will give you more info than a bore scope. The OP doesn’t even know what he’s looking for.
Thanks, however, the reason I did what I did was because the base flange gasket leaked oil pretty badly. Also, I wanted to learn something as I've never done this before.You are way over thinking this. Don’t even need to remove the engine from the equipment. To check for scoring all you need to do is remove the head and look at the cylinder. A good mechanic can quickly ( in 15 seconds ) identify a cylinder which has been damaged. You only need to be able to see the top 1/3 of the cylinder. Have you even looked at the manual I posted?
Why not? More tools the better. If you don't like tools then more for me.
I did agree with you by saying "Still cheap to pull the head. Probably needs de-carboning of the cylinder/s anyway."
You are right, I'm a novice, but that's okay. Yes, I pulled off the metal shroud and cleaned the engine fins, etc. Thanks for your support.Why not? More tools the better. If you don't like tools then more for me.
I did agree with you by saying "Still cheap to pull the head. Probably needs de-carboning of the cylinder/s anyway."
You are way over thinking this. Don’t even need to remove the engine from the equipment. To check for scoring all you need to do is remove the head and look at the cylinder. A good mechanic can quickly ( in 15 seconds ) identify a cylinder which has been damaged. You only need to be able to see the top 1/3 of the cylinder. Have you even looked at the manual I posted?
We all start someplace. Ask away if you need help.You are right, I'm a novice, but that's okay.
Good man. Got to crack some eggs to make an omelet. Take pictures with your camera not to forget where those pesky springs went LOL.Also, I wanted to learn something as I've never done this before.
56 posts on a subject is a lot…So what you are now telling us is that there are many things going on with this engone, but you’ll only give us pieces of info a little at a time. My time here is now ending as I’ve never been a fan of those who think we are here to hold their hand, but give us bad info. You started this thread saying it wouldn’t start, and to solve that problem you started throwing parts at it. When that didn’t work you figured you had a compression problem, so you figured you had to open the engine up. Before you opened it up you wanted to know how to identify a scored cylinder and bad rings. Now as I’m typing this I see that you are going to try reading the manual. From what I’m seeing you have one confirmed problem, non starting and two or three possible problems, so your novice brain says I’m going to attack this the way I want and the guys on this forum will bail me out. My last piece of advice to you is read the manual throughly and find a good troubleshooting procedure which tells you how to advance when you’ve already confused by everything you’ve done so far. Good luck in your efforts and I hope a tech more knowledgeable tech than me can guide you through you project. Bye, bye, bye.
Didn't mean to drag you through my inability with this project. I apologize if I'd misled you.So what you are now telling us is that there are many things going on with this engone, but you’ll only give us pieces of info a little at a time. My time here is now ending as I’ve never been a fan of those who think we are here to hold their hand, but give us bad info. You started this thread saying it wouldn’t start, and to solve that problem you started throwing parts at it. When that didn’t work you figured you had a compression problem, so you figured you had to open the engine up. Before you opened it up you wanted to know how to identify a scored cylinder and bad rings. Now as I’m typing this I see that you are going to try reading the manual. From what I’m seeing you have one confirmed problem, non starting and two or three possible problems, so your novice brain says I’m going to attack this the way I want and the guys on this forum will bail me out. My last piece of advice to you is read the manual throughly and find a good troubleshooting procedure which tells you how to advance when you’ve already confused by everything you’ve done so far. Good luck in your efforts and I hope a tech more knowledgeable tech than me can guide you through you project. Bye, bye, bye.
Thanks for you help. Merry Chrismas.56 posts on a subject is a lot…
If you have never done something (a particular task), then you have nothing to base your assessment on, other than what you read and what people tell you. Good luck and Merry Christmas.