Magnum 14 Frustration

[cleat 6,878]

Years ago I had an old Ford LGT165 that would randomly lose power and shut down.

Turned out to be a leaf in the fuel tank that would float over to the fuel outlet on the tank and block it off.

 

After the tractor was off for a while I guess the suction broke at the fuel outlet holding the leaf and it would float out of the way and the engine would then start.

 

Took forever to figure that one out as the leaf would move by the time I looked in and I did not see it.

 

Finally one day I did see it, hooked it out and problem was solved.

[rick 239]

^^^^^^^ I once found a similar problem as Cleat did but it was a dead insect that would plug the fuel tank outlet.  Not a WH, I had to remove the body of the cheap rider to gain access to the fuel tank to fix the issue.

[Racinbob 11,536]

As I wait for more parts to come in I'm attacking the M14 to do list in post 21. I've got things apart but haven't really done anything yet. Here's what it looks like under the head.

 

 

I'm not an engine guru like many of you are but I don't see anything abnormal. The Magnum manual says the intake is 1.38" diameter and the exhaust is 1.130". Both of these are 1.38"  Hopefully the tappet clearance is correct with the intake at .009" and exhaust at .018". Any words of wisdom? 

[ebinmaine 69,921]

23 minutes ago, Racinbob said:

Both of these are 1.38"

 

Uuhhhhhhhh.......

 

 

23 minutes ago, Racinbob said:

Hopefully the tappet clearance is correct with the intake at .009" and exhaust at .018". Any words of wisdom? 

 

Sounds about right.  

[ebinmaine 69,921]

Does that piston shake in the bore? 

[Racinbob 11,536]

13 minutes ago, ebinmaine said:

Does that piston shake in the bore? 

 

Not at all. The engine only has 134.2 hours. 

[pfrederi 18,219]

I would replace the exhaust valve with the correct one.  After it gets hot the oversize valve may not seat correctly.  How the wrong valve got in there is a mystery....

[Racinbob 11,536]

1 hour ago, pfrederi said:

I would replace the exhaust valve with the correct one.  After it gets hot the oversize valve may not seat correctly.  How the wrong valve got in there is a mystery....

 

 HOLY CRAP!!!! 

Do you suppose that two intake valves were put in at the factory? 

 

With a smaller valve it would sit deeper when it's closed. You don't think it would be too deep?

Now don't shoot me because I'm stupid. Would I need anything special to do this? Spring compressor? Something to fit the valve to the seat?  

 

Edited to add pictures.

 

Edited February 25 by Racinbob

[Racinbob 11,536]

A couple more points to ponder.

 

Remember that this tractor was only used to push snow on short drives. It never mowed and likely seldom used in the summer. I'm thinking it never happened to the previous owner. There was only 125 hours on it when I got it. Now 134.2 hours.

 

I also mentioned the sound seemed a bit excessive. Maybe caused by the valve?

Edited February 25 by Racinbob

[Ed Kennell 39,888]

On 2/16/2025 at 7:46 AM, Ed Kennell said:

Could a valve be affected by heat causing a failure to close????

 

On 2/16/2025 at 8:08 AM, Ed Kennell said:

 

This also got me thinking sticking exhaust valve.   If this is the case, you should see some burning at the seat.  

Can you see if the seat is burnt?

[Racinbob 11,536]

5 minutes ago, Ed Kennell said:

 

Can you see if the seat is burnt?

 

They both look great. Absolutely zero burn marks.  @pfrederi I don't want to doubt you but it just doesn't look like a smaller valve will seat properly. You think it would?

[pfrederi 18,219]

All I know is that all variations of Mag14 used the same part number for exhaust valve which was different from the intake valve....

 

Interesting that M-16 use the same size valve intake and exhaust  1.380"  The exhaust valve had a seat that was pressed into the block, most intake were machined.  Grasping at straws maybe there was a problem when the engine was assembled and they put in a M-16 valve... Interesting the seat part number is same M14 and M16.   I do not know if they cut the seat during assembly...

 

 

[pfrederi 18,219]

What is the engine spec #

[Racinbob 11,536]

26 minutes ago, pfrederi said:

What is the engine spec #

 

601559

Serial #2601805593

 

I found p/n 237672-s for the exhaust, 235582-s for the intake. 

 

Partstree was $130.71 and $179.62

Stens less than $20.00 each.

[squonk 42,005]

Outside of different material with an exhaust valve needing to withstand the heat, I don't see where that diameter difference is going to amount to a hill of beans. The seats are identical so it should seat.  They seat somewhere in the middle of the face. You can do 2 things:

 

Put it back together and buy a leak down tester ( which I think every body who fools with these engines should have) and do a leak down test.

 

Or buy a valve spring compressor ( which I think every body who fools with these engines should have ) and some valve lapping compound and lap the valve to see where and how well it's seating. 

Edited Tuesday at 09:16 PM by squonk

[Racinbob 11,536]

The specd difference between the two is actually more than that Mike.

The problem I have with buying the specialty tools is that I'd likely only use them once. I would do it to get this thing running again but I just want to feel comfortable that's the problem.

 

Edited Tuesday at 10:42 PM by Racinbob

[JCM 9,940]

Who would ever have thought of having an issue like this with a WH tractor with such a low run time. I feel bad and wish I had an answer for you. I commend you on your perseverance and hope you can put this problem behind you and enjoy your tractor. Good luck Bob. 

[pfrederi 18,219]

Since the problem only seems to be after it gets hot I guess you would have to do a hot leak down test 

 

Sending you a PM

 

[Racinbob 11,536]

I just checked the lash and both are spot on. With the book calling for a 1.130 exhaust valve I'm just having a hard time putting one that much smaller in there. But maybe that's me. 

I've had the generous offer of borrowing a leak down tester but since doing a hot test would require putting everything back together I figure I might as well go through the steps I outlined. With what I've already done that should eliminate everything else from being the problem. Since this tractor isn't used for anything winter related I can go ahead and mount the mower deck. There's an area out back that I want another path and it will be mostly mowing so I can recreate all the conditions except the summer heat. 

The new coil is hung up in Indianapolis along with two other unrelated packages. Who knows when it will get here. In the meantime I'm still listening. 

[Bill D 2,062]

I'm thinking bad coil as well.  Symptoms sound similar to the Onan ignition module failure symptoms.  Runs fine until hot then shuts down.  Once cool, it starts and runs fine until it gets hot again.

[Racinbob 11,536]

57 minutes ago, Bill D said:

I'm thinking bad coil as well.  Symptoms sound similar to the Onan ignition module failure symptoms.  Runs fine until hot then shuts down.  Once cool, it starts and runs fine until it gets hot again.

 

That's been high on my list pretty much from the get-go. I hope that proves to be right. I've got a new coil coming but it's been sitting in Indy for three days now. There's no rush but there's also no need for that.

[squonk 42,005]

If you can get your hands on a valve spring compressor you can take the valve out and see how it slides up and down in the guide. If it moves nice and smooth I seriously doubt that valve is your issue. You can also lap the valve and see how it seats. If it looks good move on and wait for that coil. 

 

Maybe remove the coil, hook an ohmmeter to it and try heating it with Nancy's hair dryer and see it anything changes 

[Racinbob 11,536]

T

Edited Thursday at 02:33 AM by Racinbob

[8ntruck 7,278]

  My wife says "Amen sister!"

[Pete D 253]

Ok, this is coming from a Wheel Horse neophyte.

Do these have electronic ignition that uses a pickup coil?

GMs had an issue in the 80s where the rat tail connector on the pickup coil LOOKED fine, but the wires inside were broken.  They would eventually shift enough to interrupt the spark - a tough condition to diagnose if you weren't aware of it.

Just throwing it out there on the outside chance it's applicable.  

Good luck, I'll be watching!

Edited Thursday at 02:47 AM by Pete D