42 inch riding mower (1742) won’t crank

[2002sheds]

Hi All,

I have a Scotts-branded 1742 riding mower made by John Deere. About 500 hours on the machine.


Typically, it is difficult to get the mower started in the Spring after sitting all winter. A few times the issue was solved with a new carburetor, but this time it is a different problem…
I cannot get the mower to turn over for very long at all (like 5 seconds). I have removed the spark plug and turned the flywheel by hand, I’ve replaced the battery, solenoid and starter and I have connected a battery charger/starter with only a small difference in how long the motor will crank before (seemingly) wiping out the battery’s amperage.
I also tested the ignition switch, which tested okay, and I made certain that the ground strap had a good, clean connection to the frame, as well as at the battery. And I even stuck a borescope into the cylinder and found no scoring or anything else unusual.
At one point, I was able to crank the motor for an extended period of time before shutting it off — like 15 seconds or so. The spark plug was still out, as I was simply trying to find ANY scenario in which the engine turned over. Since then, I have only had one instance where the motor turns for more than 3 or 4 seconds before giving out, stranding the Bendix gear in the up position…

Any hints as to why it is so hard to crank this motor over will be greatly appreciated!


Thanks,
David

 

[Tiger Small Engine]

Hi All,

I have a Scotts-branded 1742 riding mower made by John Deere. About 500 hours on the machine.


Typically, it is difficult to get the mower started in the Spring after sitting all winter. A few times the issue was solved with a new carburetor, but this time it is a different problem…
I cannot get the mower to turn over for very long at all (like 5 seconds). I have removed the spark plug and turned the flywheel by hand, I’ve replaced the battery, solenoid and starter and I have connected a battery charger/starter with only a small difference in how long the motor will crank before (seemingly) wiping out the battery’s amperage.
I also tested the ignition switch, which tested okay, and I made certain that the ground strap had a good, clean connection to the frame, as well as at the battery. And I even stuck a borescope into the cylinder and found no scoring or anything else unusual.
At one point, I was able to crank the motor for an extended period of time before shutting it off — like 15 seconds or so. The spark plug was still out, as I was simply trying to find ANY scenario in which the engine turned over. Since then, I have only had one instance where the motor turns for more than 3 or 4 seconds before giving out, stranding the Bendix gear in the up position…

Any hints as to why it is so hard to crank this motor over will be greatly appreciated!


Thanks,
David

So you have installed three new carburetors, starter, solenoid, and battery in the last few seasons? Why would you need to have the engine crank for longer than say 5 seconds? An engine that is running right typically fires right up. Have you gone through and done a complete tune up service? Are you sure the fuel is good? (Fresh and no water in fuel). Have you adjusted the valves?

 

[2002sheds]

Hi Tiger,

Thanks for the reply. I have replaced the carburetor once or twice in the last few years and replaced the battery, solenoid and starter this go around. I have not yet adjusted the valves (I hope to get to that later today when the rain stops), and I do have fresh fuel with no water in it. I was hoping it would start immediately, but was continuing to crank the motor in order to get fuel to the new carburetor (which maybe you are saying is still longer than needed). I will report back later today after I adjust the valves and charge the battery.


Thanks,
David

 

[StarTech]

If I found the correct IPL (S1742) you have a single cylinder OHV Briggs engine. IF so then most likely one of two things is the problem especially if the engine is stopping the top of the compression stroke.

• Valves are out adjustment causing the ACR not to work or
• The ACR on the camshaft is broken which is common on these engines.

When adjusting the valve the lower rocker (furthermost from the flywheel) is the intake. Once the valve is adjusted to .003-.005 you should the ACR bump the rocker as the engine engine approaches TDC compression stroke. If not present the camshaft's ACR is broken. And the exhaust is adjusted to .005 - .007
ACR = Automatic Compression Release

 

[2002sheds]

Hi Star,

Thanks very much for the reply. The engine is a 17.5hp Kohler Command, Model CV491S. I will research the valve clearances and whether this engine has an ACR and bring the results back to this forum later this afternoon, when the rain is supposed to end.


Thanks,
David

 

[StarTech]

Being a Kohler CV series the valve are none adjustable normally as the engine uses hydraulic lifters; therefore, camshaft would not have an ACR on it.

But the CV491-27509 spec does have a camshaft with an ACR on it. The problem if the ACR is broken you can't replace the camshaft with a new one as the Kohler has NLA the camshaft.

 

[2002sheds]

Hello Star,
Thanks again for your reply. Things are starting to make more sense (even if I don’t like some of the possibilities).


UPDATE: I just checked the photo of the mower’s ID label, and indeed the one I have is the dreaded CV491-27509… is there a way to get a peek at the camshaft to see if the ACR is broken/hung up?


Thanks,
David

 

[2002sheds]

Hello Star,
Thanks again for your reply. Things are starting to make more sense (even if I don’t like some of the possibilities).


I just confirmed that the mower I have is the dreaded CV491 spec 27509… is there a way to get a look at the camshaft to see if the ACR is broken? And can just the spring be replaced if it is the issue, or is the camshaft assembly just that — all one unit?

Thanks,
David

 

[2002sheds]

Hi Star, All,
My questions about inspecting the camshaft without tearing the motor completely apart and whether or not the spring on the ACR can be repaired or replaced just became more urgent, as I have learned that I will not be able to replace the mower with a similar gas model due to air quality laws changes in our area.

Any info about getting at the camshaft (I do have a borescope) and/or the viability of repairing the ACR will be greatly appreciated.

Thanks,
David

 

[2002sheds]

Hi Star, All,
My questions about inspecting the camshaft without tearing the motor completely apart and whether or not the spring on the ACR can be repaired or replaced just became more urgent, as I have learned that I will not be able to replace the mower with a similar gas model due to air quality laws changes in our area.

Any info about getting at the camshaft (I do have a borescope) and/or the viability of repairing the ACR will be greatly appreciated.

Thanks,
David