More problems on the 425 Kohler CH25

[Modrob]

In my last post, it was about getting in “tow mode” and about the engine quitting on bad gas, etc.
So I was able to get it moved with the Bypass Hose installed. Got it home and ordered a new push rod for the bent one. Changed the oil and filter.
Took the lifter out and bled it (it was solid as a rock) and installed the new rod. I went ahead and pulled the intake side Lifter and same thing. Put it back together last night and no start. It backfired once with a little starter fluid and choke, but never tried to start. I pulled the cover back off and all looked fine. Decided to take some compression measurements and found ZERO movement on either cylinder. Placing a finger at the plug hole no pressure coming out but could feel some suction. Took cover off other side and all look fine—all four rockers are moving when cranking…I’m lost again…

 

[Modrob]

I still have the bypass hose in place—surely that doesn’t have any effect?

 

[ponytug]

In my last post, it was about getting in “tow mode” and about the engine quitting on bad gas, etc.
So I was able to get it moved with the Bypass Hose installed. Got it home and ordered a new push rod for the bent one. Changed the oil and filter.
Took the lifter out and bled it (it was solid as a rock) and installed the new rod. I went ahead and pulled the intake side Lifter and same thing. Put it back together last night and no start. It backfired once with a little starter fluid and choke, but never tried to start. I pulled the cover back off and all looked fine. Decided to take some compression measurements and found ZERO movement on either cylinder. Placing a finger at the plug hole no pressure coming out but could feel some suction. Took cover off other side and all look fine—all four rockers are moving when cranking…I’m lost again…

Sorry for all of your troubles! My apologies if the questions sound basic.

Did you check the valve clearances? Sometimes more than one push rod is bent.

Did you look into the cylinder from the spark plug or measure the depth with a dowel? And then crank and retest? (A check for crankshaft movement.)

All the best,

Peter

 

[MossRoad]

I still have the bypass hose in place—surely that doesn’t have any effect?

No, that shouldn't have any effect on the engine. However, I'm not sure you should run the engine with the bypass in place. The pump may need to build pressure to stay lubed, etc.

As I said, I'm not sure.

The tram pump is 'in neutral' when the pedal is not pressed, so it shouldn't drag on the engine too much. It's the two sections of the PTO pumps that I think cause most of the drag. But again, that's just a guess.

 

[MossRoad]

Did you check the opposite side for bent push rods?

 

[ponytug]

No, that shouldn't have any effect on the engine. However, I'm not sure you should run the engine with the bypass in place. The pump may need to build pressure to stay lubed, etc.

As I said, I'm not sure.

The tram pump is 'in neutral' when the pedal is not pressed, so it shouldn't drag on the engine too much. It's the two sections of the PTO pumps that I think cause most of the drag. But again, that's just a guess.

You make a good point about it probably not being a great idea to run the pump in bypass mode. IIRC, I think that it just bypasses output to input, which is to say that the charge pump should still be functioning. Without the bypass, towing the tractor, the wheel motors deliver full pressure to the locked pump, where the oil is forced into a high flow bypass through the pump generating heat.

All the best,

Peter

 

[Modrob]

Sorry for all of your troubles! My apologies if the questions sound basic.

Did you check the valve clearances? Sometimes more than one push rod is bent.

Did you look into the cylinder from the spark plug or measure the depth with a dowel? And then crank and retest? (A check for crankshaft movement.)

All the best,

Peter

No problem at all with the “basic” questions. Many times I’ve found, I can overlook the simplest of things.
Let’s see: All four push rods look fine and are working. Looking into the cylinder I can see the piston moving when starter is bumped…

 

[Modrob]

No, that shouldn't have any effect on the engine. However, I'm not sure you should run the engine with the bypass in place. The pump may need to build pressure to stay lubed, etc.

As I said, I'm not sure.

The tram pump is 'in neutral' when the pedal is not pressed, so it shouldn't drag on the engine too much. It's the two sections of the PTO pumps that I think cause most of the drag. But again, that's just a guess.

I went ahead and took off the bypass hose, just in case.

 

[Modrob]

Did you check the opposite side for bent push rods?

Yes sir, both sides checked, and again just a little bit ago. All look fine. I’m gonna rig up a remote start button so I can position myself to observe better going forward.
This afternoon though, I am concerned about the right side bank (looking from rear of the tractor)…the springs look to be a little less space between them compared to the other side. Last night I just bled off the lifters, put in the new rod, and ensured there was movement in the springs and valve stem when I pushed down on the rocker with my thumbs. Earlier I was reading many articles about TDC, so maybe that’s a factor?

 

[m5040]

I would look for a timing issue. Make sure as the piston come up with the valves closed you get a spark at the top of the stroke, then watch what the valves are doing in relation to the piston position (the 4 strokes). Easy to do and no cost. Then go from there.