engine won't start - need some tips to try next

dleclair

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Hi,

I've been working on trying to get my dad's mower going but I'm running out of ideas so I'm looking for tips on what to try next.

Engine/Mower Details:
I'm working on a LV148EA-334036B engine mounted on a MTD push mower model 11A-413F516.

Symptoms:
I'm not getting any action at all when I try to start it up. I'm not even sensing any initial combustion happening.

What I've tried:
  1. At first I wasn't getting any spark from the plug. I tried replacing the plug but that didn't work.
  2. I then I used a spark tester and confirmed that there was no charge getting to the plug.
  3. Then I replaced the ignition coil and still there was no spark getting to the plug.
  4. Then I looked at how the main controller cable was pulling on the brake lever and figured it wasn't pulling it back far enough. I clamped the lever back farther and found that I was starting to get a spark from the ignition coil. On this mower, the controller cable is not adjustable so I replaced it with a new one and now I can reliably get a spark from the plug. Still, the engine won't start.
  5. Next, I took the carburetor off and opened it up for cleaning and visual inspection. It was actually quite clean and the bowl had fresh gas in it. Still I cleaned it up with carb cleaner.
  6. Before taking the carburetor off, I noticed that the choke plate would get stuck when I pulled it back and then it would spring back to its default position when I gave it a little tap. So, when I took the carburetor off I also looked around the governor lever and found that it was caked pretty thick with soot and dirt. So I cleaned it all up with carb cleaner as well. After reassembling and reinstalling the carburetor I found that choke plate was now moving freely with no guming up. Still, I had no action from my attempts to start the motor.
  7. The only other thing I observed was that there's a hole in the breather tube just before the breather tube elbow. I haven't done anything to patch or replace it because I didn't think that would explain my symptom of not getting any turns out of the motor.

So that's where I've gotten to so far. I'm still new to small engine repair so I'm well out of my depth now. I'm looking for suggestions on any tests I can perform that can narrow down where the problem is so that I can focus in on the right area. I don't like blindly just trying fixes without some other test telling me that I'm on the right track.

Thanks in advance for your help.

Denis
 

ILENGINE

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Try putting a small amount of gas into the intake and then see if it will start. If it starts then you still have a carb problem. If it doesn't start then need to look at spark and compression side of engine.
 

dleclair

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Which intake are you referring to? Is it the air intake hole at the end of the carburetor? If so, how deep do I need to inject it for it to be a valid test? Also, when you say “a small amount” how much are we talking?

Thanks.
 

ILENGINE

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Yes, air intake hole at end of carb. It doesn't have to be very much gas, I would say a thimble full or two. Just need to get enough into the carb to give it a good prime. And then crank the engine the engine should pull the fuel into the cylinder and see if it will start and run.
 

tadawson

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All that cranking with no spark, and a stuck choke, might be flooded as well. Is the plug wet?
 

dleclair

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I've seen several tips about if the plug is wet then there's no chance it will start. I've tried to look for any signs of that. The plug seems dry to my untrained eye but you know how fluid gasoline is that I don't know if it maybe it is wet and I'm just not seeing. All I can say is that the plug looks dry to me to the extent that I'm questioning if there's even any gas being pulled into the chamber to be honest. It would be nice if I could confirm that somehow.

I'm at work now so I won't be able to try the gas injection test until tonight at the earliest.

Any other thoughts or ideas in the meantime are appreciated.
 

dleclair

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I finally got around to trying the injection test this morning. I used a plastic syringe to draw 4 ml of gasoline straight from the mower’s tank and I injected it into the inlet of the carburetor. Two pulls of the starter cord and the thing started right up. I kept it running for about a minute and it ran smoothly - no knocking or anything like that. After stopping it I gave it another start without priming and it started up again.

I’m not sure that was long enough running to burn the injected fuel and validate that the regular gas intake system is working as it should but I decided to leave it as is for now. I’ll let it cool down while I work on some other things and then I’ll try to start it again normally in a couple hours.

This is encouraging. Let me know if there’s anything else I should be checking.
 

tadawson

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What you put in the carb was gone in seconds . . . it just blew through in a very rich blast, and then the carb began feeding fuel.
 

bertsmobile1

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If it won't start from cold without injecting some fuel then you are not getting the rich start fuel mix.
Depending upon exactly which carb is on there
1) choke is not closing fully ( butterfly furthest away from the engine.
2) priming system is not flooding the carb
3) idle circuit in the carb is blocked.
 

dleclair

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If it won't start from cold without injecting some fuel then you are not getting the rich start fuel mix.
Depending upon exactly which carb is on there
1) choke is not closing fully ( butterfly furthest away from the engine.
2) priming system is not flooding the carb
3) idle circuit in the carb is blocked.


I was able to get it to start from cold this morning but only barely. First I gave it about 6 shots with the primer and couldn’t get anything from it. Gave it another 6 shots and heard it fire once or twice then stop. Then I kept trying with the starter without priming and it ran for like 3 second then stopped. Gave it another prime and several more pulls on the starter and finally it was up and running.

Once it was warmed up I was able to start with a single pull no problem.

Being that hard to start from cold won’t be practical for my aging parents so I need to tune it make it easier for them. Of the options you listed above, how do I test for them and how I fix them if I find that they’re not right?

I will point out that when I press on the primer plug, I don’t feel that resistant gush that I usually get when I press it on my own mower. On theirs it almost feels as if there’s a blockage or something - that being said, I don’t know how theirs felt before and it may have always been like this.

Thanks for your help. I feel like we’re getting close now - just need some tuning.
 
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