More problems on the 425 Kohler CH25

   / More problems on the 425 Kohler CH25
  • Thread Starter
#101  
Looking at more documentation, I can’t see where the “jug” separates from the block…am I missing it?
 
   / More problems on the 425 Kohler CH25 #102  
Looks like the ch25 does not have removable cylinders
 

Attachments

  • diagram.gif
    diagram.gif
    86.3 KB · Views: 118
   / More problems on the 425 Kohler CH25 #103  
No, it does not have jugs. It's all one block. I typed jug, and immediately edited it to say block, but it was read fairly quickly. :p
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#104  
No, it does not have jugs. It's all one block. I typed jug, and immediately edited it to say block, but it was read fairly quickly. :p
Ahhhh…I’m with you now…I’m a bit slow—more everyday! LOL
 
   / More problems on the 425 Kohler CH25 #105  
I guess this means put it back together and see how it goes?
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#107  
UPDATE: March 27, 2024 FINALLY!

Back together today and nervously gave it a crank. New tank of gas, some Choke, cranked about 5 seconds and Voila! Fired right up. It seems to be “jumping” a little at this low speed. Ran it about a minute and shut it down. During that run period I thought I heard a slight “bang” but nothing changed. I’ll attach a short video of it running. Now going to add more fuel and see if it will do a little work. 😊
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#108  
For some reason now I can’t seem to attach a video..
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#109  
Well…no joy. I started it again a little bit later after adding more fresh gas. It started so quick—almost the moment I turned the key! But I shut it off quickly, because I meant to check the oil. (I had just changed the oil with the good stuff before I tore it down. But wanted to check anyway.) After I cut the key and it was dying down, I hear a low pitched kind of whine that matched the motor rpms…😯Looking at the dipstick, it was almost impossible to see, and looked very thin. I’m not sure if I smelled gas in it or not, but I’m going to drain and change anyway before proceeding…
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#111  
New oil and filter, and forgot to mention that before the initial fire up the day before, I had went through the nearly new aftermarket carb with a good cleaning. (Don’t see any obvious issues, but I thought the float moved a little too far up into the body so I tried to adjust it a little…I should have read up on it but I remembered in other cases where the seam on the float body side was to be parallel with carb body so I tried to match that…if…it moved, it was only slightly).
Yesterday hit the key and it fired right up but still seems like the motor is “jumping” a little. It smells like it is running a little rich (no smoke). It still “spiffs” sometimes after throttle is increased a little. Maybe a slight backfire from exhaust every-so-often. Overall, it is running pretty well, but not as it should, and that worries me that I don’t want to engage in any work until I know for sure.
Today gonna pull the carb again and look for issues in needle and float areas.
Oh, and spark plugs looked fine.
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#112  
Ok guys…the saga continues (but doesn’t seem to be AS BAD😊)…
Motor starts great and fast, the “jumping” (picture a motor loose mounting type of movement) is better after several startups. Low idle engine almost sounds normal with just a hint of some odd sound from exhaust intermittently. Sped up some and the sound gets worse—I think it sounds more like a miss but a minor on—if that’s even possible. And, it emits a faint smell of raw gas/running rich. I’ve pulled the carb and cleaned it twice and even pulled out the original carb after a thorough cleaning. Either one makes no difference in the running.
Suggestions? I’m thinking to pull the heads again and check exhaust valves—seems I remember that earlier, one seemed to be slightly “sticky” in moving in the head. (All was cleaned and a little lube added, but still that slight drag)
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#113  
Oh, and I needed to move my towable backhoe urgently so I hooked up and pulled it…up a little hill, increased the throttle, and it ran great under that load…
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#114  
And…I had checked the plugs last night after about a minute of run time. The right side plug was very hot to the touch, but the left side was much cooler. Both plugs looked fine with no residue/wetness/color issues…
 
   / More problems on the 425 Kohler CH25 #115  
Was the right side the one with the dented cylinder wall that you pictured earlier?
 
   / More problems on the 425 Kohler CH25 #116  
Are those new plugs?
If not that is step 1.
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#117  
Was the right side the one with the dented cylinder wall that you pictured earlier?
Yes it was/is. But I’ve since found today by pulling off plug wire from that same side, no change in motor. However, left side and engine nearly dies.
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#118  
Are those new plugs?
If not that is step 1.
Yes they were new plugs. Today I just found pulling off plug wire on the left side made no change to motor—but right side and it nearly died. So I’m thinking it’s bad coil or related. When I first moved in with my wife almost 4 years ago she had this and it was running on one side then, I found. Mice had eaten the wiring and I had to replace the coil on that right side. I’m guessing this one went south too?
 
   / More problems on the 425 Kohler CH25
  • Thread Starter
#119  
On a side note…coming off the big multi-pin connector on starter side are these three open connectors. I don’t believe they’ve ever been hooked up best I can tell. One of these wouldn’t be connected to the coil unit in some way, could it? rendering the coil inoperative? Maybe they are for options? (No gauges on this unit except an hour meter—I can’t tell if it works) and the fan had been originally disconnected by previous owner…I put one together and ran it off battery with a switch)
Also, there looks to be a switch/sensor on that starter side as well, mounted to an aluminum box on frame wall, no connection…maybe for original fan?
 

Attachments

  • IMG_5558.jpeg
    IMG_5558.jpeg
    1.7 MB · Views: 270
  • IMG_5559.jpeg
    IMG_5559.jpeg
    1.9 MB · Views: 109
   / More problems on the 425 Kohler CH25 #120  
So I’m thinking it’s bad coil or related
Right or you have no compression on that side. Suggest pulling plug, attaching plug wire, clamping spark plug flat (where wrench goes) to convenient ground, and cranking starter. Look for strong and consistent spark. If none, troubleshoot your ignition system -if looks good/strong, check compression
 

Marketplace Items

JOHN DEERE 330G SKID LOADER (A58214)
JOHN DEERE 330G...
TOOTHED BUCKET FOR MINI EXCAVATOR (A58214)
TOOTHED BUCKET FOR...
UNUSED RAYTREE REDM32 HYD MULCHER (A60432)
UNUSED RAYTREE...
2022 FORD TRANSIT 250 CARGO VAN (A59905)
2022 FORD TRANSIT...
2011 DRAGON 130BBL VAC TRAILER (A58214)
2011 DRAGON 130BBL...
2007 JLG SKYPOWER 800S BOOM LIFT (A60429)
2007 JLG SKYPOWER...
 
Top