Toro GT2300 bogging down

[radios1]

Well, I now know why I am bogging. The cylinder on the left side, or driver's side if it were a car, is only showing 800 on a compression test. The other is 1400. I was sure both cylinders tested the same when I checked them a few weeks ago, but I obviously messed up. (probably didn't clear the other side's reading). So I am guessing I've got to look into what's going on on that side.

you said the tractor was running fine until it quit because a coil wire shorted out, then you replaced the coil and fixed the wire. I don't see how this could affect compression, unless you adjusted the valves incorrectly, and didn't mention you adjusted them..

 

[Beaverplt]

I haven't touched the valves since this whole thing started. I'm thinking the engine was losing power slowly enough that I didn't notice until the engine quit when the coil shorted.

 

[tomplum]

I haven't had a head issue on a Kohler twin, but I suppose it is possible. To be intermittent one would kind of think a loose exhaust seat. What I have seen in badly egg shaped cylinder walls on one side of a Courage twin. One theory I've had is that it drops a coil on one side and running it long enough, the cylinder gets washed down so it isn't lubricated.

 

[Beaverplt]

It shouldn't be too hard to figure out. I'm going to look at it tomorrow. I only have a half day of work. My first thought is to look at the valves to see if anything looks amiss. Beyond that, maybe head gasket? I just hope it's not the piston rings.

 

[Beaverplt]

I got to work on my problem this afternoon. I removed the valve cover (1 broken bolt) and both push rods just fell out. One of them is bent. I also pulled the head off (2 more snapped bolts from the heat shield) I'm attaching some pics of the pushrods, the valves, and the piston. My first guess as an amateur is one of the valves is stuck badly enough to bend a push rod. Where I go from here, I'm not quite sure of yet. Obviously I'll be doing some research, but all help is appreciated.

 

[tomplum]

What sometimes happens is if you have a loose rocker and one push rod drops out, the other will bend from the compression. Other times the valve guide migrates forward so that the spring keeper hits the guide and bends the rod. It could migrate rearward holding the valve open also. Tying this in with an intermittent runability issue may indicate that the exhaust seat is loose. Now the valve not able to close drops the 1 rod and the other bent. The Courage has solid lifters so there shouldn't be an issue there. The need to move freely.
What I would do: Disassemble the head. The springs are light enough that you can do it with your fingers if you support the valve head. Check that the valves move freely in the guides and that the guides are in similar positions. I seem to remember that they are slightly different, but the manual should reference that. Next check out the seats to note if they are secure or show signs of being hammered due to being out of position. Decarbonize the valves and give them a roll on a smooth surface to check for trueness. I can't see from the pic if the cylinder bore shows signs of wear, but you will want to check that out too.

 

[Beaverplt]

Sounds like a good plan. I haven't given the cylinder a good look yet, but was planning on doing that before reassembly. Other than the push rods and head gasket, is there anything you would just replace rather than re-using?

I also need to get the broken bolts out of the head. The valve cover bolt should be no problem. The two from the heat shield bolts don't look like fun. My success rate with easy-outs and small bolts is near zero.

 

[radios1]

there's a few complaints about Kohler engines bending push rods. one example. bent push rods Courage engine - Google Search it seems most are caused by a valve guide coming loose and rising up to the head.

 

[Beaverplt]

Should I order new valve guides when I order the other stuff I need?

Of course when I looked up new push rods on ereplacementparts.com, I found two different numbers. My engine model 735 is listed, but the 4 numbers after the dash (0011 in my case) is not listed.

I also examined the cylinder. I do not see any obvious scoring of the cylinder walls. I am attaching a picture of the cylinder. I'm curious as to what the light brown substance is in the upper right hand corner is. It appears to be a blocked hole.

 

[tomplum]

You didn't really say what else you had found with the head. Kohler heads do not come loaded and you have to buy just about everything. Maybe a used head that looks good if you need one? If the cylinder walls look ok and you find no obvious slop where you can rock the piston sideways in the bore- that at least leans towards being fine. You certainly want head and exhaust gaskets. Others are bonus but good to have .