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Briggs vanguard fuel solenoid.

Started by Patrick NC, November 27, 2022, 09:06:44 AM

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Patrick NC

Yesterday I was sawing some cedar when suddenly my 23hp briggs died mid cut just like I turned the key off. It was a bit of a head scratcher at first. I pulled the fuel line off and the pump was working good. Checked for spark, also good. Dumped a little gas in the carb, started and died again.  While I was turning the key on and off I noticed that I could hear the fuel solenoid on the carburetor click. Started checking wires and flipping the switch and suddenly it started working again.  Got back up and running and about an hour later it happened again. Removed the solenoid and checked for trash or corrosion.  Clean as a whistle with no obvious reason why it would get stuck. It started working again after I got it back together.  No more issues the rest of the day. I've ordered a new solenoid,  but I'm a little concerned that it could be a short in the wiring somewhere.  I guess I'll have to go over everything and check for bare wires. Possibly a ground problem?
Norwood HD36, Husky 372xp xtorq, 550xp mk2 , 460 rancher, Kubota l2501, Case 1845 skid steer,

JoshNZ

Leave it idling and wriggle all the wires yep. I had this same thing happen to me absolutely dead in the water with a band buried in a log. Poked and prodded around wiring and one snapped off at the crimp joint. Have to get thrown an easy one once in a while, hopefully you too!

melezefarmer

I've had a few crimps let go at inopportune times. I now keep quick a pack of quick splice snap wiring crimps at the mill. They are not a long lasting solution but they can temporarily fix the issue until i have more time to do it properly.

Don P

An appropriate bolt will replace that solenoid in a pinch as well, you'll backfire on fast throttle downs with it gone.

Patrick NC

Apparently it doesn't do much to start with.  It backfires every time I throttle down.  Has since new. 
Norwood HD36, Husky 372xp xtorq, 550xp mk2 , 460 rancher, Kubota l2501, Case 1845 skid steer,

charles mann

Quote from: Patrick NC on November 27, 2022, 06:58:34 PM
Apparently it doesn't do much to start with.  It backfires every time I throttle down.  Has since new.
Sounds like doing away with the solenoid and plugging the hole up wouldnt have any adverse troubles. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

bigblockyeti

Quote from: Patrick NC on November 27, 2022, 06:58:34 PM
Apparently it doesn't do much to start with.  It backfires every time I throttle down.  Has since new.
That mill uses a centrifugal clutch doesn't it?  Of the mills I've been around, those with a centrifugal clutch allow the inertia of everything spinning to keep pushing the engine until it drops below the clutch coupling speed.  This allows different engines on many different mills to do the same.  I only have a 14hp Kohler on my mill and it uses a belt tensioner as the clutch so the throttle is chopped and engine decoupled at the exact same time:  No popping/afterburn.  The Woodland Mills 126 and 130 with the exact same engine and a centrifugal clutch do pop, so it's not something wrong with any of the engines, it's just a function of already running pretty lean.

melezefarmer

Quote from: Patrick NC on November 27, 2022, 06:58:34 PM
Apparently it doesn't do much to start with.  It backfires every time I throttle down.  Has since new.
I have the same mill and engine combo with the Setwork computer which slowly releases the throttle cable via a linear actuator. That could explain why mine doesn't backfires on throttle downs.

Ben Cut-wright

Quote from: Patrick NC on November 27, 2022, 09:06:44 AM
Yesterday I was sawing some cedar when suddenly my 23hp briggs died mid cut just like I turned the key off. It was a bit of a head scratcher at first. I pulled the fuel line off and the pump was working good. Checked for spark, also good. Dumped a little gas in the carb, started and died again.  While I was turning the key on and off I noticed that I could hear the fuel solenoid on the carburetor click. Started checking wires and flipping the switch and suddenly it started working again.  Got back up and running and about an hour later it happened again. Removed the solenoid and checked for trash or corrosion.  Clean as a whistle with no obvious reason why it would get stuck. It started working again after I got it back together.  No more issues the rest of the day. I've ordered a new solenoid,  but I'm a little concerned that it could be a short in the wiring somewhere.  I guess I'll have to go over everything and check for bare wires. Possibly a ground problem?
You don't mention any backfire when the engine died.  You also state you "could hear the solenoid click" each time you cycled the key.This could mean the fuel solenoid was operating properly but not *when it is supposed to. The solenoid coil activates the spring loaded plunger to ALLOW fuel flow in the carb power circuit. If the plunger was stuck you would not hear a click.  If the coil was bad or not getting voltage there would be no click. Putting fuel into the carb is a good clue that lack of fuel was the cause of the engine dying.
 
"It started working again after I got it back together" would seem to indicate *you are sure the solenoid is faulty.  No doubt you are correct when you noted the engine began running when you put the solenoid back in the carb.  And, it may be a faulty solenoid.  OR...it could have been something obstructing the orifice the solenoid plunger opens when the solenoid is activated and blocks when the voltage is turned off.  It could also be the float needle valve was sticking and eventually came unstuck.  IT happens. Could have been enough water was in the bottom of the carb bowl to stop the engine and it eventually washed out when you took the solenoid off. 

 "Apparently it doesn't do much to start with.  It backfires every time I throttle down.  Has since new"

This is a common complaint often resolved by operator techniques or the use of non-ethanol fuels of correct octane. 

Patrick NC

Mill has the same linear actuator that @melezefarmer mentioned so there's no control over how fast you throttle up or down. I've always run midgrade non ethanol gas in it. Also no backfire when it dies. Just like I shut the switch off. @bigblockyeti  may be onto something about the centrifugal force clutch 
Norwood HD36, Husky 372xp xtorq, 550xp mk2 , 460 rancher, Kubota l2501, Case 1845 skid steer,

Ben Cut-wright

There are centrifugal clutches which include engine-braking feature. These are unique and expensive. I can't see how they would be useful or cost effective for a sawmill.  If this type clutch *is employed, how does it contribute to backfiring?

bigblockyeti

Quote from: Ben Cut-wright on November 29, 2022, 11:58:16 AM
There are centrifugal clutches which include engine-braking feature. These are unique and expensive. I can't see how they would be useful or cost effective for a sawmill.  If this type clutch *is employed, how does it contribute to backfiring?
It's just a regular centrifugal clutch.  The afterburn popping that can be heard is from keeping the engine at a higher rpm than it wants to be for a longer time than if the inertia of two wheels wasn't attached to it. 

Patrick NC

Yep. Sorta like rolling downhill with an old manual transmission truck with your foot off the gas. 
Norwood HD36, Husky 372xp xtorq, 550xp mk2 , 460 rancher, Kubota l2501, Case 1845 skid steer,

bigblockyeti

Quote from: Patrick NC on November 29, 2022, 03:09:54 PM
Yep. Sorta like rolling downhill with an old manual transmission truck with your foot off the gas.
Exactly!

Gearbox

That is the anti diesel solenoid .it has nothing to do with backfires . It just chops the fuel off when you turn the ignition off.
A bunch of chainsaws a BT6870 processer , TC 5 International track skidder and not near enough time

Don P

Ahh, I think the foggy memory is parting, its been a few years since that problem. We've had a couple of backfire issues since new. With the solonoid gone I think it was sending one last charge of unignited fuel at the hot exhaust when I keyed off. The original carb has since been replaced with another oem one.

Ben Cut-wright

Quote from: Patrick NC on November 29, 2022, 03:09:54 PM
Yep. Sorta like rolling downhill with an old manual transmission truck with your foot off the gas.
No, it isn't anything like that.  The above is an example of "engine braking", which the common centrifugal clutch isn't capable of.  During operation of a common centrifugal clutch the engine drives the clutch. When the engine decelerates there is NO provision for the driven components to drive the engine.  As the engine RPM's drop below spring pressure the centrifugal clutch friction shoes do not contact the drum. If the engine stops providing power, for any reason, the clutch will immediately disengage. 

bigblockyeti

Quote from: Ben Cut-wright on November 30, 2022, 10:36:41 AM
Quote from: Patrick NC on November 29, 2022, 03:09:54 PM
Yep. Sorta like rolling downhill with an old manual transmission truck with your foot off the gas.
During operation of a common centrifugal clutch the engine drives the clutch. When the engine decelerates there is NO provision for the driven components to drive the engine.
This is incorrect, when decelerating the clutch shoes are still in contact with the drum and the speed of the motor shaft is still high enough to keep them firmly so until dropping below the couple speed.  Above the couple speed (and within the torque limit of the clutc) the engine can drive the load or the load can drive the engine.  Only clutches with a sprag would allow overrun, those without will not.

Ben Cut-wright

Quote from: bigblockyeti on November 30, 2022, 11:21:26 AM
Quote from: Ben Cut-wright on November 30, 2022, 10:36:41 AM
Quote from: Patrick NC on November 29, 2022, 03:09:54 PM
Yep. Sorta like rolling downhill with an old manual transmission truck with your foot off the gas.
During operation of a common centrifugal clutch the engine drives the clutch. When the engine decelerates there is NO provision for the driven components to drive the engine.
This is incorrect, when decelerating the clutch shoes are still in contact with the drum and the speed of the motor shaft is still high enough to keep them firmly so until dropping below the couple speed.  Above the couple speed (and within the torque limit of the clutc) the engine can drive the load or the load can drive the engine.  Only clutches with a sprag would allow overrun, those without will not.
Another member states his mill has the identical engine, clutch, and throttle control as the OP has.  His does not backfire on decel.

My comments included enough information to describe how the common centrifugal clutch works.  Your reply mostly agrees with what I said right up to "the load can drive the engine".  AS the engine in this setup decelerates the clutch shoes do remain in contact with the drum down to decouple RPM's.  But not because the engine is being driven by the load, as in "truck rolling downhill".   The *engine will continue to DRIVE the load as long as those friction shoes are contacting the drum, not the other way around. in other words, the load decelerates because the engine RPM's are lower but still driving the load. IE: not decelerating, but providing energy to drive the load (at a lower RPM).


Until the centrifugal force (created by ENGINE RPM's at part throttle) drops low enough so that the spring tension pulls the friction shoes away from contact with the output drum,  the engine *dictates RPM's.  "your foot off the gas rolling down the hill" does NOT decouple the clutch. Nor does it equate to slowly lowering engine rpm until the centrifugal clutch *decouples. 

bigblockyeti

I think we're trying to say the same things in different terms.  The standard centfiugal clutch will not decouple after being coupled (by increasing the engine speed) until dropping below the decouple speed tuned by the spring(s) within.  It does not matter whether the engine supplied torque is maintaining speed above the couple speed or the load is driving the engine through the clutch to keep it above couple speed.  Torque, once the clutch is engaged and held above couple speed, can travel from the engine to the load or from the load to the engine.

Regarding the afterburn popping, that can be tuned from any engine by enriching the pilot circuit in the carburetor.

JoshNZ

What big block is saying makes sense. If a second engine were connected to the mills bandwheels through some hypothetical frame and coupling, and brought up to full RPM, you could in theory shut the mills engine down completely and provided the second engine maintained RPM, the mills engine would be driven indefinitely by the engaged clutch (there is no one way sprag to disengage it if torque is in the other direction, nor is it like a pull start reel where the shoes/dogs only engage in one direction). It's a brief moment of this situation that might be experienced after throttling off due to the bandwheels inertia.

My band pulls up pretty darn quick after letting go of the throttle however! I think my engine with the belts removed (completely decoupled from mill) would take longer to return to idle than the wheels take to stop when throttle is released.

Ben Cut-wright

Quote from: JoshNZ on December 01, 2022, 02:42:05 PM
What big block is saying makes sense. If a second engine were connected to the mills bandwheels through some hypothetical frame and coupling, and brought up to full RPM, you could in theory shut the mills engine down completely and provided the second engine maintained RPM, the mills engine would be driven indefinitely by the engaged clutch (there is no one way sprag to disengage it if torque is in the other direction, nor is it like a pull start reel where the shoes/dogs only engage in one direction). It's a brief moment of this situation that might be experienced after throttling off due to the bandwheels inertia.

My band pulls up pretty darn quick after letting go of the throttle however! I think my engine with the belts removed (completely decoupled from mill) would take longer to return to idle than the wheels take to stop when throttle is released.
You may very well be trying to explain something I cannot grasp.  But the way it reads (bolded) describes an impossible situation. A typical centrifugal clutch requires the engine driving the clutch shoes be operating at an rpm high enough to engage the clutch friction shoes with the output drum.  If the primary engine is shut down, no force can be transmitted back to that primary engine via the clutch drum. Doesn't matter how fast the drum is being turned by other sources, the drum will never cause engagement with the friction shoes.  

Patrick NC

I can tell you for a fact that if the engine dies mid cut, the clutch stays engaged until right before the blade stops.
Norwood HD36, Husky 372xp xtorq, 550xp mk2 , 460 rancher, Kubota l2501, Case 1845 skid steer,

JoshNZ

Quote from: Ben Cut-wright on December 02, 2022, 10:31:39 AMDoesn't matter how fast the drum is being turned by other sources, the drum will never cause engagement with the friction shoes.  
That is correct it will never cause engagement from disengaged but if "other sources" takes over at full RPM it would keep them engaged. The shoes are not kept engaged by torque from the main engine but by their weight being thrown outward at the drum causing the drum to spin also. If you use other sources to spin the drum and then put a load on the hub/shoes without slowing anything down, they will continue to stay engaged so long as the whole mechanism is spun at sufficient rpm.

If the shoes are stuck to the drum with enough force to transmit milling torque, that force is going to be plenty to keep them spinning and stay engaged, even with a dead chugging engine trying to stop them.

Once stopped, you'd never get them engaged by spinning the drum again of course.

That's how I see it at least, I may be missing something. I can't see a reason for shoes to slow down so they don't disengage so they can't slow down so... etc..

Ben Cut-wright

Quote from: JoshNZ on December 02, 2022, 01:29:04 PM
Quote from: Ben Cut-wright on December 02, 2022, 10:31:39 AMDoesn't matter how fast the drum is being turned by other sources, the drum will never cause engagement with the friction shoes.  
(1) The shoes are not kept engaged by torque from the main engine but by their weight being thrown outward at the drum causing the drum to spin also.


(2) If you use other sources to spin the drum and then put a load on the hub/shoes without slowing anything down, they will continue to stay engaged so long as the whole mechanism is spun at sufficient rpm.

(3) If the shoes are stuck to the drum with enough force to transmit milling torque, that force is going to be plenty to keep them spinning and stay engaged, even with a dead chugging engine trying to stop them.

(4) Once stopped, you'd never get them engaged by spinning the drum again of course.

(5) That's how I see it at least, I may be missing something. I can't see a reason for shoes to slow down so they don't disengage so they can't slow down so... etc..
Appreciate your interest.  The clutch discussion got the topic a bit off track.  I do not believe clutch or driven components is causing any of the backfire conditions.  I'll try once again to explain my point as to centrifugal clutch operation.

(1) Indeed, the friction shoes are KEPT engaged by centrifugal force provided by the running 'main engine' and NOTHING else.

(2) Think about this. The friction shoes are in contact with the drum because the 'main engine' RPM's are sufficient to overcome the return spring.  The friction shoes are hub mounted to the engine crankshaft.  When the engine ceases to create sufficient RPM's for the friction shoes to contact the drum, the shoes are retracted because of spring tension.
 
(3) Surely you see why it is impossible for the drum to transmit energy back through the friction shoes when the 'main engine' is no longer running?  Nothing CAN drive the friction shoes that WERE in contact with the drum because the spring retracted them when the 'main engine' crankshaft RPM's became too low to create centrifugal force. The friction shoes aren't rotating, only the drum is rotating.  There is no force from the rotating drum creating centrifugal force for the friction shoes.
 
(4)

(5) HTH

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