Tecumseh LV195SE lawn mower engine won't start.

[kjonxx]

valves gap is wrong set to .010 on both

 

[Cfs]

Have you removed the spark plug and replaced it with a new one or a known good plug? Also try adding some gas through the spark plug hole… replace the plug and attempt to start it. If it pops and runs even for a few seconds you know it’s a fuel delivery problem.

I should have asked if the spark plug was wet after your prior efforts to get it to start… before trying this.

If it’s not getting wet…gas is not being drawn into the cylinder. That could indicate a compression problem or possibly an air leak on the intake manifold. Something to look at.

Compression on small engines can be difficult to measure…. Briggs used to recommend turning the engine on its side (carb side up of course) spark plug wire disconnected. Turn the blade backwards against the compression stroke and the blade should spring back slightly. If there is no ‘rebound’ the compression is an issue. If there is a noticeable rebound there is probably enough compression for it to start per Briggs.

I know this is a Tecumseh but the mechanics behind it still applies..

Spit

 

[Dave T S]

valves gap is wrong set to .010 on both

How do you rest the valve gaps, thanks.

 

[Rivets]

This manual should help you out. https://www.mymowerparts.com/pdf/Te...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf

 

[Dave T S]

This manual should help you out. https://www.mymowerparts.com/pdf/Te...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf

Thank you.

 

[TobyU]

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.

 

[Johner]

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.

Try changing spark plug.

 

[Dave T S]

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.

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.

 

[TobyU]

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.

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.

 

[Tiger Small Engine]

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.

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.