Sticking valve?

[formariz 12,337]

This is what this K321 is doing. Started with severe backfiring. It’s not the carburetor or spark plug. Could it be timing moved or a sticking valve?

 

[ri702bill 10,232]

Hmmm... almost sounds like lack of fuel. Or a bad condenser.

Do a cylinder leak-down test. Air escaping out the carb means a valve issue - could be a bad valve , sticking, or a chunk of carbon holding the valve off its seat....

[Handy Don 14,858]

I don’t see the governor trying to throttle it up. Is the idle speed set too low? Governor not working or adjusted?

That it seems to eventually starve out says “fuel” to me.

[squonk 44,740]

I would look at the points/timing. I just got a 7HP running and it sounded just like that until I set the gap and timing

[formariz 12,337]

Tractor had been fine for years. This was a sudden problem. Pump is pumping fuel properly, cleaned carb no change. Changed carb to a new one no change. Spark is fine, changed spark plug anyway, no change . Changed condenser no change. It’s why I am leaning to a valve problem . The sound of air escaping when throttling up is what makes me think that. Last attempt at it now will be to redo the timing. If that doesn’t work seems like I’ll have to look into valves. 

[Handy Don 14,858]

6 minutes ago, formariz said:

If that doesn’t work seems like I’ll have to look into valves. 

Take a peek under the valve cover?

[gwest_ca-(File Mod) 11,775]

Try a shot of Marvel Mystery oil or 2-stroke oil in the fuel and run it. That should lubricate the valve stems.

[formariz 12,337]

1 hour ago, Handy Don said:

Take a peek under the valve cover?

Looked into that but that is going to require at least removing carburetor again. Its in the back of property, I am going to have to tow it to shop to work on it. Getting tired of walking back and forth to get another tool.

[Lee1977 7,418]

Might want to see if the valves are adjusted right while you have the carburetor off. 

[squonk 44,740]

Normally a sticking vale will make the miss consistent. That miss is not. I think the air you hear is the unburned fuel charge coming out of the exhaust or perhaps a head gasket starting to go.

[formariz 12,337]

1 hour ago, squonk said:

Normally a sticking vale will make the miss consistent. That miss is not. I think the air you hear is the unburned fuel charge coming out of the exhaust or perhaps a head gasket starting to go.

The air mixed with fuel comes out of carburetor. Happens when throttling is increased and then it stalls. No visible signs of anything coming through head gasket. 
 When I get it to shop I’ll check timing. Hopefully it’s that. 

[squonk 44,740]

15 minutes ago, formariz said:

The air mixed with fuel comes out of carburetor. Happens when throttling is increased and then it stalls. No visible signs of anything coming through head gasket. 
 When I get it to shop I’ll check timing. Hopefully it’s that. 

Now that's something. If it's puffing out of the carb, it's almost gotta be the intake valve not seating.

[formariz 12,337]

9 minutes ago, squonk said:

Now that's something. If it's puffing out of the carb, it's almost gotta be the intake valve not seating.

I been thinking valves too after eliminating all the other possibilities. As for timing I never had one run bad because of incorrect timing. They would just not start if timing was not spot on. Even working this way it starts immediately on first crank. 

[formariz 12,337]

Now I am stumped! Timing is correct and valves look like they are working fine. At least not sticking. 

[lynnmor 8,140]

You said it's not the spark plug but did you try a new one?

[8ntruck 8,239]

Since the valves seem to be working, the other way to get backlow through the carb might be a crankcase breather that is not quite right?

[formariz 12,337]

24 minutes ago, lynnmor said:

You said it's not the spark plug but did you try a new one?

Yes actually 2different new ones

[formariz 12,337]

11 minutes ago, 8ntruck said:

Since the valves seem to be working, the other way to get backlow through the carb might be a crankcase breather that is not quite right?

Removing that now for inspection and cleaning

[Bill D 2,393]

Run a jumper between the battery positive and the coil positive and see if the problem goes away.   Could be a bad key switch or dirty/corroded connection.  After it's been running for awhile a high resistance connection in/at the key switch can heat up causing voltage loss to the coil and cause it to cut out.  Had this happen on a cub I fixed for a friend. 

Edited October 24 by Bill D
Spelling

[formariz 12,337]

Got it. Absolutely hard to believe. My first instinct when it first happened it was to clean carb. No change then I went and changed condenser to a new one. Same problem. I actually changed it again today to another new one my last new one in stock. Same problem. So, condenser that was originally in tractor was changed a couple of months ago as a routine maintenance I do. Along with that one all new ones were from same batch bought at Amazon.  Not knowing what else to do today I decided to to canibalize a NOS 301 stealing the condenser. Bang. No more problems. What are the odds that all three condensers were bad the one in tractor lasting only a couple of months. 
  The only good thing out of this was that tractor got a major service including cleaning the head, but almost at the expense of my sanity. Is this a common occurrence with these parts today?
 Thank you every one for all the suggestions and support. 

[702854boy 323]

11 minutes ago, formariz said:

Is this a common occurrence with these parts today?
 

From what I've read on this forum, yes, almost all parts made these days are junk.

[squonk 44,740]

16 minutes ago, formariz said:

Got it. Absolutely hard to believe. My first instinct when it first happened it was to clean carb. No change then I went and changed condenser to a new one. Same problem. I actually changed it again today to another new one my last new one in stock. Same problem. So, condenser that was originally in tractor was changed a couple of months ago as a routine maintenance I do. Along with that one all new ones were from same batch bought at Amazon.  Not knowing what else to do today I decided to to canibalize a NOS 301 stealing the condenser. Bang. No more problems. What are the odds that all three condensers were bad the one in tractor lasting only a couple of months. 
  The only good thing out of this was that tractor got a major service including cleaning the head, but almost at the expense of my sanity. Is this a common occurrence with these parts today?
 Thank you every one for all the suggestions and support. 

I watch a local auto shop guy on YT. Guy is brilliant. He had a truck in the other day that another good mechanic gave up on. Turned out the other mechanic was right with his diagnosis but installed a defective fuel pump relay, "Just because it's new, doesn't mean it's good! " Not only a lot of new parts aren't good, good parts are hard to get. And it doesn't matter if they are USA made or not. A lot of places are going the OEM used route it's getting so bad

[tunahead72 2,581]

23 minutes ago, formariz said:

... all new ones were from same batch bought at Amazon... What are the odds that all three condensers were bad ...

 

Apparently high enough that we should all consider not buying electrical parts from Amazon.  I've heard similar stories about spark plugs bought there, some counterfeit as it turned out.

 

This is going to seem unrelated, but bear with me...

 

One of my very favorite guitarists at the moment is a guy named Davy Knowles.  The first time I had the pleasure of seeing him play live, he mentioned one of his albums, at which point a guy in the crowd yelled out that he had just bought a copy off Amazon.  At which point Davy suggested very politely that we not buy his albums off Amazon, because "that man has enough of our money".  I think of that every time I consider buying anything there.

 

Glad you got this sorted out @formariz 

 

3 minutes ago, squonk said:

I watch a local auto shop guy on YT. Guy is brilliant...

 

You may have already shared this Mike, but who is this guy?

 

[Handy Don 14,858]

54 minutes ago, formariz said:

but almost at the expense of my sanity.

I doubt there is anyone paying attention to this thread that hasn’t questioned their sanity over some mechanical problem. We make for interesting company. Very glad you’ve come through in the end!

 

For me, right now, it is a generator on the bench that simply won’t fire at all--tomorrow’s problem. 

[squonk 44,740]

33 minutes ago, tunahead72 said:

 

Apparently high enough that we should all consider not buying electrical parts from Amazon.  I've heard similar stories about spark plugs bought there, some counterfeit as it turned out.

 

This is going to seem unrelated, but bear with me...

 

One of my very favorite guitarists at the moment is a guy named Davy Knowles.  The first time I had the pleasure of seeing him play live, he mentioned one of his albums, at which point a guy in the crowd yelled out that he had just bought a copy off Amazon.  At which point Davy suggested very politely that we not buy his albums off Amazon, because "that man has enough of our money".  I think of that every time I consider buying anything there.

 

Glad you got this sorted out @formariz 

 

 

You may have already shared this Mike, but who is this guy?

 

South Main Auto