42a707 Won't Start - Troubleshooting help

[Madscrills]

Bert you're awesome, man. I"ll give that a check and do the rest of the maintenance you've suggested and hopefully have a nice running mower. Thanks!

 

[YT125]

The valve clearance rarely needs to be adjusted on these opposed twins. AS I said before these have an undersized starter designed for a single cylinder and slow cranking is very common. Pull the head's and clean up the carbon built up in the cylinder and cylinder head. IF it still cranks slow then replace the starter. These engines will carbon up faster then a single cylinder and will cause slow cranking.

 

[Mikel1]

Great information Bert, thanks!

Also in my zeal I forgot to mention a few things about the mower that I forgot to mention beforehand. Upon doing some research I remembered that back when the mower originally stopped running the engine would start to try to turn over but wouldn't even make it a full rotation. After a few more tries of this is when the engine seemed to stop trying at all. I tried turning the top by hand to see if it would still spin freely and it would not. It had seized up. Upon doing a little research I learned that usually meant that the compression was making it so that the engine couldn't turn anymore and removing the spark plugs would relieve the pressure and allow the engine to spin freely again. Hence why I ended up just replacing the spark plugs altogether.

In any case, could that be the beginnings of a larger problem down the road or was that likely just due to the battery going bad? Is there a way to prevent the engine from seizing up once the new battery eventually bites the dust?
Also, it seems to only really like to start easily if I set the throttle to full and pull the choke out. That's how I've always had to start it, is that normal or is there a way I can help it start easier and only have to choke when it's flooded? Thanks again for all of ya'lls expertise with this, it's really helping.

Most likely your battery was going bad already.
Why would you choke it when it's flooding?

 

[Madscrills]

Update: I found a belt that works! It was far simpler than I thought. Turns out murray is walmart brand and I just went down the street and was able to find a belt that fit. Done.

Secondly, I changed the oil and tested compression. Each cylinder is getting about 80 psi. Which from what I've gleaned is a decent psi. Now, onto something completely different.

After I checked the compression I popped the spark plugs back in and re-assembled the hood in order to take it for a test drive. Lo and behold it doesn't start. You can imagine my confusion as it was working before I checked the compression. It was turning over and would eventually make a click click clicking noise as it was turning over. really very strange. So I took the liberty of pulling the plugs out again and both of them had been hit by "something" and had smashed the spacing down onto the electrode. You'll find images of one of the spark plugs at the bottom of this post. I re aligned the spacing and slipped them back in. Tried to start it again and had the same issue. Removed both plugs and this time only one of them had been smacked. So I fixed it again, put them back in and (This is probably very stupid of me at this point but I'm sitting here thinking to myself "It was just working fine a moment ago!") it started up this time... So I took her for a drive around, engaged the blades to make sure the new belt was cutting and it all ran fine but was a bit slower than I remembered. Seemed to bog down on grass that it shouldn't have an issue with. It might have a little bit to do with the old gas that is in it though, I haven't changed that out since last season. So anyway, I park her back in the garage and notice a little smoke coming from the engine. I watch it for a bit just to make sure it doesn't catch fire and eventually it subsides. So I remove the plugs to have another look and sure enough the right spark plug has been smashed back down...

A little back story on this. The other day when I drove to Autozone to get a new battery I also bought new spark plugs. I brought one of the old ones as reference and the woman was able to find me one that she said would work. These new plugs are slightly longer than the old ones but they didn't seem to be any longer in the threaded part (the piece that goes into the engine) So I didn't anticipate it being an issue. So there's that.

I spoke to my father who is a master senior mechanic and his advice after I sent him these pictures was that I either have the wrong plug or I have serious engine damage. He advised me to make sure I get the right plugs and to give it another go and see what happens.

Thoughts on all this fellas?

 

[Madscrills]

Why would you choke it when it's flooding?

I don't know man, I'm a noob just trying to learn a little bit about my mower.

 

[bertsmobile1]

The plug you have in yor hand is a projected electrode plug
You will need to fit a standard plug.
The difference is the center electrode in a standard plug is te same height as the threaded outer section so it does not poke as deep into the combustion chamber
If you are using an NGK it will have al the same letters but no P.

 

[Mikel1]

I don't know man, I'm a noob just trying to learn a little bit about my mower.

It's okay:smile:

Make sure you get the right plugs.

 

[ILENGINE]

You need either a champion J19LM, and I hate champion plugs, or a NGK B2LM They have a 3/8 reach with a washer and not beveled like the plug in the picture.

 

[Madscrills]

Coincidentally before I checked the forum just now I had already purchased the aforementioned plug and tried it out. You guys are right! That was the problem. It's starting and running great now!

So now my mower seems to be working completely now. Ready for the grass cutting season. Now I just need to hop on over to the lawn care section and find out how to get rid of these dang weeds and see how to better care for my grass. Thanks to everyone for all of your help! I had a productive day today. Not only did I get my mower working completely but I also installed my garage door opener! Good weekend. Take care guys and thanks again!

 

[Tinkerer200]

The valves very seldom need adjusting on these engines and is not easily accomplished. Your symptoms do not indicate valve problems. Holding the key on too long trying to force the starter to turn the engine causes the starter to over heat and reduces the electromagnetic strength of the armature windings. Done enough times or for too long completely ruins the starter. Three seconds per attempt is a good max.

Walt Conner