Scag Wildcat ('04) - stwc61a-27cv Not Starting

[five2loves42]

I am having an intermittent starting issue with my stwc61a-27cv ('04 with 362 hours) . It was hard starting and would run the battery down (old battery '04 with only 156/300 cranking amps left when I had it tested), so replaced the battery. This is after checking the fuses and kill switch settings on the drive and mower deck.

It would crank, but not start. Did not smell like it was flooding. In fact seemed like it was not getting fuel or spark. I check and was getting spark. Fuel was coming to the filter out the other side, but did not check further.

Found somewhere online that there was a low oil switch to prevent starting. I had checked the oil and it was between the add and full marks (3/4 of the way to the full mark). I added oil to the full mark and it started fine. Is this a pressure switch or level switch (oil change is coming up so it may have lost viscosity and tripping the no start ?). Also, is there a hydro-oil lockout switch as well? Could this be viscosity on the hydro-oil as well? I have not changed the hydro-oil since I bought this from a friend last year.

Mowed the area around the house (4ac) and shut it down and restarted several times.

I tried to start it and same symptoms as above (grrrr). Check the oil and it was still at the full mark were it was at when I started mowing (really glad there because I was afraid of oil consumption, but that was not the case).

Of course when I went out to check the hours it started on the first crank!!

I am really struggling here. My next step is to check the fuel shutoff solenoid when it fails to start to see if it is getting voltage when I crank, but need someone to help test this.

Any other ideas?

Thanks for your help,

TomV

 

[Mad Mackie]

Hi Tom,
Low oil level switches are generally not installed on machines that are self propelled, but on stationary equipment like generators, etc.
Installed in the carb is a fuel shutoff solenoid that will stop fuel flow into the carb high speed jet when the key is in the off position. When you turn the keyswitch from off to on, you should be able to hear this solenoid open. This solenoid can be removed and inspected both visually and electrically. Only do this with a cold engine as some fuel will drain from the carb. Sometimes there can be an accumulation of crud buildup on the tip of the plunger in this solenoid and sometimes they can fail. Other spots to look at are where all the ground wires are connected onto one of the engine mounting bolts, battery cables, fuel fill cap vents. With the exception of the starter motor, all power comes thru the keyswitch and the connector that plugs onto it. Check these areas for problems. If you are not comfortable doing these steps, then find someone with experience with small engines.
This is probably the manual for your machinehttp://www.scag.com/OpManuals/STWC/2004STWCOPMAN/2004STWC-OPMANcomplete03141.pdf
You can find the manual for your engine on the Kohler website, but you will need the model, type number and serial number from your engine.

 

[Mad Mackie]

This should be a better link to the Scag manual.
403 Forbidden

 

[five2loves42]

Mackie,

Thanks for the quick reply!

My Kohler manual had "Incorrect Oil Level" as a non-start item, that is why I went that way. Just did not know if this model had it or not.

Next time it does it, I'll check for voltage at the Fuel Shut-off solenoid to see if it is getting juice. If there is voltage, I'll pull and inspect the solenoid for the dirt on the plunger issue.

I'll post back with results.

Thanks again,

Tom V

 

[five2loves42]

I had a no start last weekend, so I was prepared to take the fuel shutoff solenoid off to clean it on the next day, but it started.

My father-in-law thought it might be running lean, so I checked the plugs and they look fine (see attachments). Do you agree?

Once it started, I pushed the choke back and came up to full throttle. Just to test, I pushed the choke back to FULL and the engine did not miss a beat! So I started looking at the choke linkage. It appeared to be fine, I would move the choke lever to FULL and the linkage would move near the carb to close the choke, but nothing happened to the engine running, no sputtering, like the choke did not close at all.

So this leads me to believe I have a choke issue and when it is cold (below 70deg) and it needs choke to start it fails, but warmer and it starts without choking.

Has anyone else seen these symptoms and/or have an suggestions on where to start with the choke?

Thanks,

TomV

 

[Mad Mackie]

Hi TomV,
The choke cable connects to a mechanism that changes the motion 90 degrees and has at least another link arm that connects to the choke plate arm. This linkage may be missing, disconnected or bent. You will need to remove enough of the carb air inlet ducting to see this linkage and what is happening to it. Also I suggest that you get all the engine info, go to Kohlers website, find parts manuals for your specific engine model and series, download it and look at the carb and controls sections to see the parts involved in the choke system. There is also the possibility that the choke plate in the carb may have come loose, so check all this out.