Will Crank, But Will Not Start... 417A with a 17 HP Kohler Engine

[the jeep driver 30]

Hello.   My 1985 Wheel Horse 417A with a 17 HP Kohler Engine will turn over, but will not start.  It looks to be getting fuel, I can see gas in the carb...   I did try starting fluid, no start.  I changed the spark plugs, as the old ones were due anyway, and used an inline spark tester to verify spark.  I don't know what to test next.  Any help is appreciated!  

[ri702bill 12,966]

Fuel, air, spark, & compression. Ya need all four to rave it run.  The spark - is it a strong blue-white color or pale yellow? Is the timing correct ? - right spark at the wrong time in the cycle equals a no run condition.

Edited September 6 by ri702bill

[953 nut 69,062]

This manual should be helpful.

 

[the jeep driver 30]

2 hours ago, ri702bill said:

 The spark - is it a strong blue-white color or plae yellow? Is the timing correct ?

The spark is blue/white, I don't know about the timing. 

 

1 hour ago, 953 nut said:

This manual should be helpful.

 

Thank you.

[Ed Kennell 47,230]

9 hours ago, the jeep driver said:

The spark is blue/white

 

14 hours ago, the jeep driver said:

I can see gas in the carb.

That leaves air and compression.         Has the tractor been sitting for a long time?    Do you have compression?    Possible stuck valves.

[peter lena 10,046]

@the jeep driver  how does the carb throttle plate , easily fit / sit  in its  closed position ? done a lot of  that  detailing , made for instant  starts , now regular on my 3 horses . pete

[the jeep driver 30]

6 hours ago, Ed Kennell said:

 

That leaves air and compression.         Has the tractor been sitting for a long time?    Do you have compression?    Possible stuck valves.

No, the tractor was last used 8/22 or 8/23 and it ran fine.  The only difference between that mowing and prior was that I had to mow in the rain for about 20 minutes.  I parked it in the garage, and didn't clean it off as normal... I usually blow all the debris off when finished.  When I wanted to mow on 8/30 it wouldn't start and after messing with it for a while, I borrowed my neighbors mower.  
I do not have a manometer for compression testing... I did see on how to make on in the manual 953 posted, haven't had time to make it... I may see if anyone I know has one.  

[oliver2-44 11,730]

Most auto supplies loan out compression gauges.

They require a deposit but refund it when you return the gauge. 

I'm not that familiar with the Kohler twins, so I checked and best I can tell the Kohler twins DO NOT have a compression release like the single cylinders.

So you should be able to get a good compression reading. 

[Ed Kennell 47,230]

5 hours ago, the jeep driver said:

No, the tractor was last used 8/22 or 8/23 and it ran fine.  The only difference between that mowing and prior was that I had to mow in the rain for about 20 minutes.  I parked it in the garage, and didn't clean it off as normal... I usually blow all the debris off when finished.  When I wanted to mow on 8/30 it wouldn't start and after messing with it for a while, I borrowed my neighbors mower.  
I do not have a manometer for compression testing... I did see on how to make on in the manual 953 posted, haven't had time to make it... I may see if anyone I know has one.  

I know you said you have a good strong spark, but it surely smells of an electrical problem.   Could the spark plug wires be old and wet enough that they are shorting before the spark gets to the plugs?       Remove the air cleaner and try cranking it in the dark while you look for fire in the plug wires.

Edited September 6 by Ed Kennell

[the jeep driver 30]

On 9/6/2026 at 7:11 PM, Ed Kennell said:

Remove the air cleaner and try cranking it in the dark while you look for fire in the plug wires.

I did this last night, I didn't see anything in the wires.  I haven't had time to do any other tests.  

[the jeep driver 30]

On 9/5/2026 at 6:42 PM, ri702bill said:

 The spark - is it a strong blue-white color or pale yellow? 

Finally had time today to work on the tractor; redid the basic tests to see if I missed anything; now the spark in my inline test is yellow/orange.... I am thinking failing coil now.  Thoughts on sourcing parts? 
 https://www.amazon.com/dp/B07T13RXLX?lv=shuf&channelId=500&plpRedirect=mhFallback.  This is on the low end cost-wise, and I could have it here tomorrow but very few reviews on it.  Everything else I'm seeing is a couple hundred dollars at least.  
 

[pfrederi 21,134]

9 minutes ago, the jeep driver said:

Finally had time today to work on the tractor; redid the basic tests to see if I missed anything; now the spark in my inline test is yellow/orange.... I am thinking failing coil now.  Thoughts on sourcing parts? 
 https://www.amazon.com/dp/B07T13RXLX?lv=shuf&channelId=500&plpRedirect=mhFallback.  This is on the low end cost-wise, and I could have it here tomorrow but very few reviews on it.  Everything else I'm seeing is a couple hundred dollars at least.  
 

Not sure you coil is the problem...but a Harley Davidson 2 cylinder coil which can be had cheap has been used successfully.

[the jeep driver 30]

On 9/28/2026 at 6:01 PM, pfrederi said:

Not sure you coil is the problem...

What are you thinking then?  I have not gotten the coil yet.... 

[the jeep driver 30]

On 9/6/2026 at 8:24 AM, peter lena said:

@the jeep driver  how does the carb throttle plate , easily fit / sit  in its  closed position ? done a lot of  that  detailing , made for instant  starts , now regular on my 3 horses . pete

It looks fine to my untrained eyes.  

[pfrederi 21,134]

Is the spark equally weak on both plugs.  The KT coil is two separate coils in one package.  odd both sides would partially fail equally.

[953 nut 69,062]

Have you disconnected the condenser to see if spark will improve? 

 

[the jeep driver 30]

19 hours ago, pfrederi said:

Is the spark equally weak on both plugs.  The KT coil is two separate coils in one package.  odd both sides would partially fail equally.

Yes, both plugs have yellow spark.  

[pfrederi 21,134]

Seems like you have eliminated a lot of potential issues if disconnecting the condenser doesn't work I would try the coil you found