Magnum 14 Frustration

[Racinbob 11,536]

I posted about this last summer and still haven't solved the issue but with spring nearing it's on my mind again. I found a 1996 314-H with about 120 hours on it in Ohio. The only way to state the condition is to say it's like a new machine. There were still factory tags on it and absolutely spotless front to back. It had only been used to push snow and the PTO never even had a belt on it. I paid top dollar for it but was very happy to do so knowing what I found. Unfortunately, after a summer of frustration I named it Buyers Remorse and parked it in the barn for the winter. Here's the issue.

I put a 42" mower deck on it and it would now be my wifes mowing tractor. Then, after about 20 minutes of mowing it acted like it was running out of fuel. It would die on her then she could limp it back to the garage. Guys, there a multitude of things fuel related that could cause this. Multiple times I repaired or replaced something thinking I may have it solved. Nope. The 20 minutes isn't exact but it's an accurate way of describing the problem. No matter what I did the problem didn't change at all. 20 minutes and it acted up. I took the seat and it happened to me and the only difference was I was able to play with the choke and nurse it back without it dying. It's gotta be fuel delivery related, right? I assure you, with what I've done, it's not. 

I pulled the tins off to inspect the ignition module. I checked the primary and secondary impedance, shined up the magnets and gapped. I pulled the muffler and checked as best as I could. Put it back together and gave it another try. 20 minutes and it puked. I realize these two items can be affected by the heat so................?

At that point winter was coming and I had other things to do so it was either the scrap yard or park it and start fresh when spring nears. The barn it was.

I have not checked the valve clearance yet. In the near future I'll get it back in the garage and check that. If that within specs then..................?

Maybe a valve hanging up as it gets hot? 

Maybe the heat causing the ignition module to act up? At first I thought this was a $200-300 part and not something to throw at it just to see but I've found aftermarkets units for about $30 so not it is.

Maybe heat causing a muffler restriction? I will say it does seem abnormally loud for a stock muffler. Not a lot but more so than my Command 15 with a similar muffler. 

Best case scenario here is I find the issue. My wife says she might like the hydro so fine. I've got high hopes for the Dino C-121 8 that I'll be completing so that would be an option for our second mowing tractor and we wouldn't need this 314. In any case I have to find the issue. It would be up to her which one she wants to mow with. 

I'm all ears guys. 

[ebinmaine 69,921]

I believe you're headed down the right path. 

Patience and perseverance of course are key but there's a line to be drawn between practicality of time spent vs making it a personal pride issue to find the cause.  Both are fine. That decision is yours alone. 

 

 

I'd wonder if it has the super low hours because the previous owner(s) couldn't/ wouldn't  fix the issue(s) so it spent time "parked" as it did in your own possession. 

 

 

 

Do you have a muffler to swap on?

I'm not a fan of pepper pots but they do breathe well. (Hence they're louder.) Perhaps adapt one on there. 

 

I like the ignition swap idea but I'd be be FAR more prone to get a used known good original from Brian Badman or Jake Kuhn.  Reliability of cheapo aftermarket 💩 parts can be questioned occasionally and I'd want the good reliability of OE if possible. 

 

 

The valves really should be checked as well. I'm not sure how you could check them hot though...

 

 

 

 

[midpack 938]

It sure sounds fuel related, does the gas tank cap breathe?

[Racinbob 11,536]

4 minutes ago, midpack said:

It sure sounds fuel related, does the gas tank cap breathe?

 

It sure does but it isn't. Everything from the gas cap to the bolts holding the carb on have been checked and replaced. 

Replaced cap, new valve/strainer in tank, new fuel line and filter, electric fuel pump, rebuilt the original Walbro carb twice then replaced with a new carb.

Edited February 16 by Racinbob

[David Blanchard 14]

Original fuel line? Maybe clean the carb and try it again.

 

[Racinbob 11,536]

5 minutes ago, David Blanchard said:

Original fuel line? Maybe clean the carb and try it again.

 

All new quality line. Rebuilt the carb twice and then replaced with new. Every step it was 20 minutes and puke. Nothing changes one bit. 

[David Blanchard 14]

Realy does sound like fuel issue but sometimes I have used inline B&S spark tester to verify the spark stays strong &blue not yellow and weak  just enough for engine to stay running

[Racinbob 11,536]

11 minutes ago, David Blanchard said:

Realy does sound like fuel issue but sometimes I have used inline B&S spark tester to verify the spark stays strong &blue not yellow and weak  just enough for engine to stay running

Yup. I know it does. But I'm confident it isn't. The spark it strong but I wonder if the coil heating up might be a thing. 

[Ed Kennell 39,888]

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

[ri702bill 8,787]

My money is on a bad coil. Had one on a 7HP Kohler that you could set your watch by - 7 minutes. Did the inline spark checker - great spark when cold. After it heated up 7 minutes later - no spark.

[Racinbob 11,536]

8 minutes ago, Ed Kennell said:

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

 

I was wondering about that Ed. I guess the head has to come off to check that. I'm not sure what to look for to determine that. Or what to do. 

 

8 minutes ago, ri702bill said:

My money is on a bad coil. Had one on a 7HP Kohler that you could set your watch by - 7 minutes. Did the inline spark checker - great spark when cold. After it heated up 7 minutes later - no spark.

 

I'm thinking I should just get one of those aftermarket coils coming. 

 

It's obvious this tractor had the issue when I bought it. But I truly believe the seller didn't know about it. First, he seemed like a great guy. Then, considering it was only used to push snow it never saw the heat conditions that summer mowing brings. 

[peter lena 9,002]

@Racinbob  agree on the spark , another thing I do  on  new to me engines , is to run it on a seperate gallon of heavily treated fresh fuel , by passing the  tank to  carb  possible issues , pete

[Ed Kennell 39,888]

3 minutes ago, Racinbob said:

I'm not sure what to look for to determine that.

 

1 hour ago, Racinbob said:

it does seem abnormally loud for a stock muffler.

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

[Racinbob 11,536]

2 hours ago, peter lena said:

@Racinbob  agree on the spark , another thing I do  on  new to me engines , is to run it on a seperate gallon of heavily treated fresh fuel , by passing the  tank to  carb  possible issues , pete

 

As I mentioned, eliminate the fuel thing. There's no issue there.

Edited February 16 by Racinbob

[953 nut 56,884]

1 hour ago, Racinbob said:

Maybe heat causing a muffler restriction? I will say it does seem abnormally loud for a stock muffler. Not a lot but more so than my Command 15 with a similar muffler. 

To me if something is abnormal then it is a clue on the direction to look at. Run it with another muffler o see what happens.

[Racinbob 11,536]

1 minute ago, 953 nut said:

To me if something is abnormal then it is a clue on the direction to look at. Run it with another muffler o see what happens.

 

Another excellent point. I did pull the muffler but all you can really check for is loose baffles and there wasn't. I could just install a pepper can muffler for testing purposes. Ya know, kinda like the old catalytic test tube. For testing purposes only.............but the test never ended.  

[squonk 42,005]

Thinking coil or...

 

Any chance this tractor has a kill relay? Weak coil in the relay starts to give up the ghost after 20 minutes and tries to ground out the IGN coil?

[squonk 42,005]

18 minutes ago, Racinbob said:

 

 Ya know, kinda like the old catalytic test tube. For testing purposes only.............but the test never ended.  

Got to knock out that fuel tank inlet so the regular gas nozzle will fit!   

[Racinbob 11,536]

2 minutes ago, squonk said:

Thinking coil or...

 

Any chance this tractor has a kill relay? Weak coil in the relay starts to give up the ghost after 20 minutes and tries to ground out the IGN coil?

 

That's possible but I'm thinking that would be a go/no-go instead of go/ try to go thing. The seat switch apparently seems to be bypassed 

[Racinbob 11,536]

2 minutes ago, squonk said:

Got to knock out that fuel tank inlet so the regular gas nozzle will fit!   

I forgot about that step. 

[Racinbob 11,536]

This is incredible but not unexpected here. I started this thread about an hour ago and already so much help. 

Thanks everyone and keep the ideas coming. 

 

So far I think this is my plan:

 

1) Order a head gasket and a coil

2) Get the tractor in the garage. 

3) Check valve clearance

4) Pull head to inspect

5) Replace coil

6) Install exhaust 'test pipe' 

 

If I find something obvious along the way the steps could stop or be delayed. The plan is subject to modification based on more ideas from you all. 

 

 

 

[pfrederi 18,219]

1 hour ago, ri702bill said:

My money is on a bad coil. Had one on a 7HP Kohler that you could set your watch by - 7 minutes. Did the inline spark checker - great spark when cold. After it heated up 7 minutes later - no spark.

 

 

I have had the cheap Harbor Freight spark tester flash yet the engine wouldn't run right.  Hooked up the B&S tester and you could see the spark was yellow and weak.

[Ed Kennell 39,888]

Bob, did you have a spark tester on at the 20 minute mark.  Any difference in the spark when she got ill..

 

Oops,I see Paul types faster than me.

Edited February 16 by Ed Kennell

[ebinmaine 69,921]

4 minutes ago, pfrederi said:

B&S tester

 

Is this a tester that can be left in place without being held by hand ?

[pfrederi 18,219]

6 minutes ago, ebinmaine said:

 

Is this a tester that can be left in place without being held by hand ?

 yes

 

Edited February 16 by pfrederi