425 Problem

[SnowRidge]

maybe OT, but I ran out of gas today. I was surprised when I refilled the tank that it did not self-prime the fuel line.

The reason was is the way the fuel line is looped, and the very small diameter prevented the air trapped in the line from flowing out. I ended up having to squeeze all the air out of the line, and mess around with the filter to get most of the air bubble out of it. Possibly something is caught in that little elbow on the tank (although I can't see anything), cause I couldn't get the last bit of air out.

I think a straight nipple attached to the tank and a new larger diameter hose are in my future.

I took my hose off and ran a piece of flex wire up the elbow. It started flowing a lot better after that.

 

[pajoube]

O.K.

So now after the carb kit was installed by the Kohler dealer the machine gets hot quickly and loses power. Appears to be a symptom of running lean, correct?

Yes, that would be my take.
I changed out the fuel filter which had allot of junk in it right after replacing the carb back on. Do you think I could have small particles into the fuel pump? Or into the fuel solenoid?
PJ

 

[MossRoad]

Yes, that would be my take.
I changed out the fuel filter which had allot of junk in it right after replacing the carb back on. Do you think I could have small particles into the fuel pump? Or into the fuel solenoid?
PJ

Sure. That could be possible. A blockage could cause a lean condition. As could the float not opening enough. Or a jet too small of a size.

 

[pajoube]

Sure. That could be possible. A blockage could cause a lean condition. As could the float not opening enough. Or a jet too small of a size.

Neighbor is a mechanic at the airport - waiting for him to wake up (night shift) and take a look at unit.
PJ

 

[J_J]

Yes, that would be my take.
I changed out the fuel filter which had allot of junk in it right after replacing the carb back on. Do you think I could have small particles into the fuel pump? Or into the fuel solenoid?
PJ

The clogged fuel solenoid caused me to waste time on taking the fuel solenoid off and cleaning, and it usually worked after that. Just need a small piece of wire, maybe air. I usually put voltage to it to make sure it worked. You can see it move and hear it click.

 

[MossRoad]

Neighbor is a mechanic at the airport - waiting for him to wake up (night shift) and take a look at unit.
PJ

Great. Let us know what you find.

 

[Charlie_Iliff]

Neighbor is a mechanic at the airport - waiting for him to wake up (night shift) and take a look at unit.
PJ

Paul:
Any progress?

 

[pajoube]

Paul:
Any progress?

These past couple of weeks has been interesting in regards to my 425 problems.
Had mechanic check out the carburetor and it was working well.
By-passed to check the cooling fan and it was working.
Checked the thermostat and it was bad so ordered a new one.
Installed the new thermostat but that did not help run fan during hot temperatures.
Checkout the thermal coupler and ordered new one.
Checked all wires and found the fan wire was unplugged, very hard to get to and fix.
Still having engine power problems even though the cooling fan is now working properly.
Mechanic stated that I have oil coming through the rings and that is why power is reduced.

Question, mechanic stated that I may be better off getting new engine instead of doing the rings based on the number of hours on the engine (900). What do you guys think?
PJ

 

[MossRoad]

These past couple of weeks has been interesting in regards to my 425 problems.
Had mechanic check out the carburetor and it was working well.
By-passed to check the cooling fan and it was working.
Checked the thermostat and it was bad so ordered a new one.
Installed the new thermostat but that did not help run fan during hot temperatures.
Checkout the thermal coupler and ordered new one.
Checked all wires and found the fan wire was unplugged, very hard to get to and fix.
Still having engine power problems even though the cooling fan is now working properly.
Mechanic stated that I have oil coming through the rings and that is why power is reduced.

Question, mechanic stated that I may be better off getting new engine instead of doing the rings based on the number of hours on the engine (900). What do you guys think?
PJ

A couple years ago when we visited you mentioned an oil consumption problem. Perhaps it is time to resolve it. As for a rebuild.... what is the price and is the mechanic sure that will solve it? What is the price of a new engine + labor to install it? Big decision.

If I were in your situation I would consider the following:

These engines are supposed to last about 1500 - 2000 hours under normal use.

If the cost of a rebuild was only 1/3 to 1/2 the cost of a new engine, I would go with a rebuild and hope it lasts another 450 hours.

If the cost of a rebuild is going to cost more than 1/2 of the cost of a new engine + installation costs I would probably opt for the new engine and keep the old engine in clean storage for parts.

 

[pajoube]

A couple years ago when we visited you mentioned an oil consumption problem. Perhaps it is time to resolve it. As for a rebuild.... what is the price and is the mechanic sure that will solve it? What is the price of a new engine + labor to install it? Big decision.

If I were in your situation I would consider the following:

These engines are supposed to last about 1500 - 2000 hours under normal use.

If the cost of a rebuild was only 1/3 to 1/2 the cost of a new engine, I would go with a rebuild and hope it lasts another 450 hours.

If the cost of a rebuild is going to cost more than 1/2 of the cost of a new engine + installation costs I would probably opt for the new engine and keep the old engine in clean storage for parts.

Thanks David,

Your right about the cost. Also not to mention if I can get the same engine. The frame is so tight you do not have much room to play with. There is no doubt that I have worked the engine much beyond what it was designed for. As I can not get along without the 425 in top condition I may consider the new engine. I have asked what it would cost for a ring job but no answer as of yet.
PJ

 

[MossRoad]

As I recall, all of your pumps are in front of the engine, correct? That should be a bit easier to replace VS my model with pumps fore and aft of the engine as you won't have to cut the housing on the opposite side of the shaft.

 

[toy]

Thanks David,

Your right about the cost. Also not to mention if I can get the same engine. The frame is so tight you do not have much room to play with. There is no doubt that I have worked the engine much beyond what it was designed for. As I can not get along without the 425 in top condition I may consider the new engine. I have asked what it would cost for a ring job but no answer as of yet.
PJ

Seems like I remember from somewhere that the engine was bolted to a plate and that the plate was bolted to the bottom of the pt frame, if so it might be easier to unbolt the plate and raise the engine and do whatever work needed and then lower the plate with the motor mounted on it and then bolt the the plate back down. I don't know if that is right or not but if it is that might make a big difference in working on it.

 

[pajoube]

Seems like I remember from somewhere that the engine was bolted to a plate and that the plate was bolted to the bottom of the pt frame, if so it might be easier to unbolt the plate and raise the engine and do whatever work needed and then lower the plate with the motor mounted on it and then bolt the the plate back down. I don't know if that is right or not but if it is that might make a big difference in working on it.

You guys are great, going to check this out tomorrow.
I will try and keep everything running until late fall when machine is not used much.
PJ

 

[pajoube]

As I recall, all of your pumps are in front of the engine, correct? That should be a bit easier to replace VS my model with pumps fore and aft of the engine as you won't have to cut the housing on the opposite side of the shaft.

Yes, that is correct.
Mowing every three days now, no hills but able to reverse my mowing to go down hill for the most part.
PJ

 

[3238dpw]

PJ I am not as experienced as some with PTs but I have a lot of experience with the 25 hp Kohlers, which I believe you have. They are on both of my mowers. First of all, the mechanic I use all the time and trust said that those engines are not worth rebuilding. He said he has rarely ever seen one not have problems after being rebuilt weather it was rebuilt by him or someone else. Once you dig into them something is just not right. My experience has been with a burnt valve. I had another engine with bad compresion on the other head so I swapt the heads. With in a few months it developed an oil leak. I took it to him to fix the leak and he said he would do it but it could easily come back. It did with in a 100 hrs of use. That is just my experience, take it for what it is worth.

My vote is if you are on the fence get a new motor. How about the fuel injected 28 hp Kohler. From what I understand it is the same engine you have now with a different cam, compression, etc. So it should fit. From talking to Scarg on the phone(liquid cooled 29hp Kaw motor) he said more hp made a huge difference in his machine.

 

[pajoube]

PJ I am not as experienced as some with PTs but I have a lot of experience with the 25 hp Kohlers, which I believe you have. They are on both of my mowers. First of all, the mechanic I use all the time and trust said that those engines are not worth rebuilding. He said he has rarely ever seen one not have problems after being rebuilt weather it was rebuilt by him or someone else. Once you dig into them something is just not right. My experience has been with a burnt valve. I had another engine with bad compresion on the other head so I swapt the heads. With in a few months it developed an oil leak. I took it to him to fix the leak and he said he would do it but it could easily come back. It did with in a 100 hrs of use. That is just my experience, take it for what it is worth.

My vote is if you are on the fence get a new motor. How about the fuel injected 28 hp Kohler. From what I understand it is the same engine you have now with a different cam, compression, etc. So it should fit. From talking to Scarg on the phone(liquid cooled 29hp Kaw motor) he said more hp made a huge difference in his machine.

Thank you for the note and your experience, this really helps.
PJ

 

[hogi]

What about this as a possible replacement engine?
40hp Engine Horizontal 1 1/8" or optional1 7/16" Shaft - eBay (item 190311449701 end time Jun-29-09 17:08:38 PDT)

 

[3238dpw]

That engine would be awsome except it probably wouldn't fit. I don't know that though. I am just going by what scarg said to me about it took him a ton of reserch to find an engine with more hp that would fit. That is why I suggested another Kohler. Of course it still may be worth looking into, unless that much power would overwelm the pumps and cause damage.

 

[woodlandfarms]

In a random way I will second what scott says in regards to rebuilds (not kohler specific). I knew a small engine repair guy who basically told me over a beer that rebuilts are lucky to get another 3rd of life (it runs 1000 hours and fails, maybe you will get another 300 after rebuild).

 

[hogi]

That engine would be awsome except it probably wouldn't fit. I don't know that though. I am just going by what scarg said to me about it took him a ton of reserch to find an engine with more hp that would fit. That is why I suggested another Kohler. Of course it still may be worth looking into, unless that much power would overwelm the pumps and cause damage.

Look at the dimensions, it's actually smaller than the 25hp Robbin in width and only slightly longer.