Mower engine high idle and stalling

Hi,

I have a Bunton 48" walk behind mower with an Onan E125V (12.5 HP) motor that will start, but seems to idle very high with the choke on. If I move the throttle cable out of the choke position it starts to die out, unless I move it back to the choke position.

There was some old fuel that I recently siphoned out, replaced with new fuel and fuel and air filters. Previously it would start fine, but then stall either in the middle of mowing or soon after being started - either way it wouldn't start again for a while. Now I can start multiple times in succession, but with the above noted problems.

I checked position of the throttle plate and cable, seems to be operating OK and in the correct position, so I'm not sure if I have a governor issue or what at this point. Thanks for any help!

 

You have a restriction in the carburetor from old fuel and the throttle plate is probably stuck for the same reason. A carb cleaning is in order.

 

And when Cheese says carb cleaning he probably means that it needs to be removed from the engine. Disassembled, soaked and cleaned to make sure all the internal passages jets and orifices are clear. Simply getting a can of carb cleaner and spraying the outside or down the throat of the carb will not do it.

 

Thanks, I started looking for a carb repair kit last night before I go taking it apart, but couldn't find anything yet. I don't own an ultrasonic cleaner, guess will have to look for a place that does.

 

I would suggest putting a strong dose of Seafoam in the fuel tank it will clean up a lot of the varnish, its worth a try. Have a good one. Geo

 

High idle with the choke on could well be an intake leak also.

 

Yep, I thought about that too but the mention of old fuel that was in it pushed me towards a clogged carb. Especially since that's the problem 90% + of the time.

 

I found the part # both for the Onan carb rebuild kit (146-0561) and a new carb (146-0526). The rebuild kit is about $135 and a new carb $185, I've looked several places and can't seem to find a good deal. Kind of rich for my blood when I'm not sure it will solve the problem.

 

Just be mindful when you take it apart to not tear gaskets. They usually will pop apart without and damage. Clean it well, and put it back together. I wouldn't buy the kit at that price unless I just had to have it. This will cost you nothing other than some time and a can of good quality carb cleaner.

 

I haven't had time to take the carb apart and give it a good cleaning yet, but took a short video of the issue I have. It definitely doesn't idle this high functioning normally.


https://www.dropbox.com/s/ntxqvpgmwgfdaps/20160925_211257_9264965294034.mp4?dl=0

 

You really should try a strong dose of SeaFoam, it will work wonders on an engine with old gas left in it. Have a good one. Geo

 

https://www.dropbox.com/s/78pywpbcy5u7re9/20170714_204042_10502179892125%20%281%29.mp4?dl=0 I finally got around to cleaning the carb. I put it back together, was able to get the machine started. However, I had trouble getting the throttle and choke linkages working again. The choke plate I believe is in the closed position right now.

 

Excellent video, loosen the screw that clamps the cable and pull the cable upwards, making it pull the linkage farther than it is and see if you can't get the choke to move. It looks like it's connected right and working the throttle correctly, just not pulling it far enough.

 

Thanks a bunch, I was hesitant to try that before your response, but glad you talked me into it.

I took two more videos. The one below is after I took the carb apart again. The issue is that the throttle linkage is loose - looks like the plastic clip is broken. Maybe a small washer to hold it in place? https://www.dropbox.com/s/apenvj71btnrsl7/20170721_142427_4645783778501.mp4?dl=0

 

Next video is after I got it running again. Since the throttle linkage is not connected, the mower idle can't really be controlled at the moment if I'm using it to mow.

Also, not sure what the proper idle should be - don't want it too low or too high of course. Not sure if this requires a governor adjustment of some sort? https://www.dropbox.com/s/cpu75sw29izpsz6/20170721_141846_4306075187298%20%281%29.mp4?dl=0 Once again, the help is so much appreciated!

 

I think I'm gonna get a little tachometer to figure out the engine speed. $20 on Amazon.

 

Yes, as the throttle cable pulls the control arm upwards, it should reach a point where it moves the rod that you loosened. That rod wasn't what I was saying to loosen, the cable clamp is what needs loosening so that you can pull the cable up so that when you put the throttle all the way up, it will engage the choke portion of the controls and close the choke. It should only engage in the last 10% or so of the travel.

 

https://www.dropbox.com/s/ejoh5knc9i...15428.jpg?dl=0

Thanks for the follow up help. I linked a pic to the plastic clip that broke while I was trying to take it apart, it was brittle. Not sure if there is a suitable replacement out there, I spent time looking but came up short. This connects the throttle cable rod to the carb.

 

Look up a parts breakdown for a kohler CV15S... they used a similar clip on the throttle shaft that will probably work as a direct replacement for yours.

 

Thank you! Yes, part # 25-158-08 does look pretty similar and is available online.

 

That's not the one... it's the bushing clip that holds the throttle linkage to the governor arm. Lemme go see if I can find a # for it.

 

25-158-11-S

This should fit the bill.

 

Thanks - I'll give that a shot this week.

 

The part came, was able to modify it a little and was working on tweaking the throttle linkage. However I ran out of gas, went to restart it and the pull rope broke..d'oh! Will have to order a new rope and try again.