# 24 hp Briggs surging and dies when hot



## jack13man (Apr 28, 2008)

I'm back again....this time I might be in over my head. I have volunteered to try and help a neighbor with his mower. He has a Husqvarna that he obtained from a brother and it has several problems. I am not sure if they are related but here they are.....1st the engine surges while running at full throttle unless choked.....2nd it starts running really rough after about an hour or so of use.
I thought I would try to fix the surging first if they are not related. All my previous experience (which is very little) has been with the smaller 2 to 5 hp.
I figured the surging was due to a dirty carb condition and I did a quick cleaning but replaced nothing. Although the carb looked clean some of the gaskets could be bad so I figured I would order a rebuild kit. Are the jets removable in this carb? Since it is still surging I would guess it still has a restriction somewhere. Are there other conditions that would cause this surging? 

Model 446677
type 0463 E1
Code 050117YG

Any help you can give me would be greatly appreciated. Thanks, Jack


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## bgbass (Jan 11, 2008)

If you need to choke to smooth out its sucking air spray some carb. cleaner around mating surfaces when running and see if it smooths out also spray around throttle shaft.As far as dieing when hot check gas cap to make sure vent is not plugged


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## jack13man (Apr 28, 2008)

I did spray around the carb and anywhere else I could get to and I did not notice any change. I will spray again. After talking with my neighbor a little more I now understand this has been doing this for some time. The surging has been going on for quite a while but the rough running started not so long ago. Would running with the choke on do any damage? After talking with him I don't think it would die but I will change caps with mine and see if it improves. (I will have to wait for the carb kit before I put it back togethe.) When mine was acting up last year I found out, with all the help here, that it was an bad ignition module. If and when I get it running without surging I will check for spark as soon as it starts running rough. Any help you can give me would be greatly appreciated. Is there anything else I can be looking at while I wait for the carb kit to arrive? Thanks


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## phillipmc (Jan 27, 2008)

I think it is the carb. I had the same issue on a 17HP briggs would idle fine but at high idle i would surge. Rebuilt the carb and it runs like new again.


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## jack13man (Apr 28, 2008)

I do believe it is the carb.....I cleaned it again ( still waiting on the rebuild kit) and tightened everything down and it made a big difference. Now it doesn't surge but it does need to be slightly choked. I mowed with it for about 45 minutes and had no change in it. I did notice something tho......the voltage gauge is jumping constantly while at full throttle. If I bring the throttle down the gauge evens out...as soon as I open up the throttle the gauge surges but the engine sounds ok......Related or a different issue????? 
Thanks again


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## phillipmc (Jan 27, 2008)

The reason the gauge needle jumps is because the output of voltage is changing when the engine surges. Can prolly ignore that safely it should be fine when the engine is running correctly


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## jack13man (Apr 28, 2008)

still waiting for the carb kit. I started it up yesterday morning and it started surging again right away. I pulled the choke out a little and it smoothed out so I guess I'm convinced the carb kit should take care of that(hopefully) However even while surging the voltage needle stayed consistant and was not moving as it was the night before after mowing.....any ideas or thoughts? thanks


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## jack13man (Apr 28, 2008)

I have been reading everything I could concerning this issue and have some questions.......It seems the 2004 and 2005 Briggs 24 and 26 hp ELS motors may have had a design problem with the air cleaner letting dirt into the intake causing engine wear. Could this cause any of the problems that I have been posting about or am I reading too much...Seems like some of the issues I read about might match up but you guys are the pro's....Thanks


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## phillipmc (Jan 27, 2008)

Engine wear is low power, burning oil, knocking/broken connecting rod, ect... It could cause a dirty carb condition. But that will be fixed when you clean and rebuild the carb. Dont read to much into that stuff.


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## light mechanic (Jul 18, 2008)

Jack you are right they have problems, have replaced several, B&S says no but when pushed they will give a new engine, problem is, the same kind, guess they have to get rid of them some how, Light Mechanic


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## jack13man (Apr 28, 2008)

Thats an argument my neighbor can have. The carb kit arrived today so I will be rebuilding the carb tonight. I am puzzled by this mower.....when I started it Sunday it would surge when on idle and when wot....last night when I started it to move it there was no surging .....I didn't put it under a load either time but I wouldn't have thought it would change.....You guys must go half nuts sometimes trying to figure some of these things out.......thanks again for the help....I'll let you know how it goes...


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## jack13man (Apr 28, 2008)

Ok, I rebuilt the carb last night and now have no surging. After running for about 45 minutes both with a load and no load...... success.....now something different.....while cold it would throttle up and down just fine....Idle was good...maybe a slight little miss here or there but it sounded good. After getting hot it still sounded good but when I went to move from wot to idle the rpms didn't change much. Does it sound like something related to the carb ...as in maybe something is together wrong or could this be related to the "heating up and losing power" that my neighbor said it was doing? Even manually I couldn't move the governor arm much. I didn't give it much time before I abandoned it for the night rather disgusted. Any help or ideas would be welcome. Thanks


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## light mechanic (Jul 18, 2008)

possible a valve setting on order, Light Mechanic


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## jack13man (Apr 28, 2008)

Thanks light mechanic...here is what it is doing.When cold it idles and throttles pretty well.....both with a load and without a load....after warming up it doesn't idle back down when no load is on the mower. Once the blades are engaged it will idle down pretty decent. I went back through the carb and everything looks ok....am I missing something? I will check the valve clearance again.( I only checked 1 side and It looked ok) Any other thoughts on this.....My neighbor told me to keep this as long as I needed so I have plenty of time to learn on this. Thanks again for all your help.


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## ossaguy (Dec 3, 2008)

jack13man said:


> Ok, I rebuilt the carb last night and now have no surging. After running for about 45 minutes both with a load and no load...... success.....now something different.....while cold it would throttle up and down just fine....Idle was good...maybe a slight little miss here or there but it sounded good. After getting hot it still sounded good but when I went to move from wot to idle the rpms didn't change much. Does it sound like something related to the carb ...as in maybe something is together wrong or could this be related to the "heating up and losing power" that my neighbor said it was doing? Even manually I couldn't move the governor arm much. I didn't give it much time before I abandoned it for the night rather disgusted. Any help or ideas would be welcome. Thanks


I was wondering what happens if you manually move the throttle shaft from fast to slow? I've seen it where if there was a lean condition,in the pilot system,it would result in a slow coastdown.If it seems fine when you manually work the throttle shaft on the carb,you may want to try doing a static governor adjustment.I've seen it to where after you do a static governor adjustment to recalibrate it,it fixes it too,but I'd think that the if the governor was not tight,it would be doing it constantly,but I've seen a lot of weird things.Just something to possably consider,is all.

If that governor is like most,you manually set the throttle shaft at idle,then move it to WOT,while watching which direction the governor arm shaft moves.( CW,or CCW) That will dictate which direction you want to turn the shaft,with some vicegrips or a pin if it's got a hole drilled thru it,after loosening the hold-down nut on the arm,all this while the thottle plate is in the fast position.If it's off,it's only going to be by just a skosh.The fact that it does it only when hot makes me think it's still carb related but thought this was worth looking into,to be sure it's calibrated right.Usually if it isn't,the top no load speed will be higher than normal,and under load it won't pick up good,and will be slow to respond from low to high with no load.
I hope you get it solved!
Steve


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## jack13man (Apr 28, 2008)

I seem to be having trouble posting so I am trying for the 3rd time.....Thanks Steve...It appears that the throttle shaft will return to the idle adjustment screw but the engine does not slow much. Does this seem to indicate I still have a carb issue? Is so anything specific I can look for? With the blades engaged it will throttle up and idle fine....without the blades engaged it does not idle down. I would like to eliminate the carb before I move on to othere things. I will check the valves tonight though. My neighbor let me know yesterday that he has, in the past, had a dealer work on this machine twice( for the surging and the run rough we hot problems) and it had not been corrected. He doesn't remember what they did or even told him about it. This problem is different than what he had before. ( At least its not surging) Thanks again for the help.

Jack


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## jack13man (Apr 28, 2008)

After thinking about this for several days I am inclined to believe I still have a carb issue. I think it is still sucking air in somewhere. When I rebuilt the carb I believe it was the air cleaner gasket that was a metal gasket. I know what I took off of the carb was a (for lack of the proper word) fiber gasket. Could this be causing my problem? Could it be sucking air pass this when it gets hot? It doesn't surge but it just won't idle down. Thanks


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## ossaguy (Dec 3, 2008)

If the air cleaner gaskets not sealing right,it will have a dirt injestion problem,but since it's on the outside of the venturi,it won't affect the fuel mixture,except if some dirt goes into the air bleed passage that works the low speed circuit.Was that passage totally clear? One place that will, cause a lean airleak are around the carb's throttle shaft.Does that have any slop in it? Another place is the intake manifold where it bolts to the block.Those things are upsteam of the carb mixture.Since it doesn't slow even if you manually have the throttle shaft closed at the idle screw,my guess would be still a problem in the carb.Spraying wd40 with the straw on it,around suspected air leak places while it's idling will pinpoint an airleak pretty good,as others have pointed out already.Are you positive that when the carb is in your hand,that there isn't any problems with the throttle butterfly plate? At idle,look close to see how it fits in relation to the tiny pilot circuit holes.My guess would be that maybe a new carb is going to be needed.Sometimes what happens is when cleaning a carb,guys blow air in the big-end of a passageway,and that just forces the obstruction deeper where it can't get removed.( Like trying to blow a basketball thru a funnel...) In the shop I've been replacing more carbs than rebuilding lately,since the success is a sure thing vs. maybe a comeback and no customer would want to pay for a new carb on top of a rebuild.
Keep us posted on what you find,it sure is a good mystery!

Steve


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## jack13man (Apr 28, 2008)

I went back through the carb...1st of all the metal gasket is the intake...the old one was a fiber.....not the air filter gasket.... I have tried spraying when running and could not find any leaks. I will try again tonight. However I went over that carb really close and I believe I found one of the small pilots obstructed. I completely dismantled and soaked for several hours and I will put back together tonight. Could the metal gasket cause any problems. If I have the problem after warm-up I will carefully spray all around the surfaces. A new carb is like $160 bucks and it might be the way to go. With all your help it is still fun to work on these. (of course it's not mine and I'm not doing this for a living......good thing too...LOL) Thanks for the help.
Jack


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## jack13man (Apr 28, 2008)

After cleaning the carb I re-installed and the motor ran good...throttled up and back to idle really nicely both cold and warm. Then......I mowed.....New problem....after mowning for 30 minutes or so I noticed a little popping and possible backfiring. It would do this both with a load and without. Full throttle and on idle. Am I right in beleiving I still have a carb issue?

Steve.....I checked the throttle butterfly and everything looks ok to me...thats not saying much is it. I sprayed WD40 all around the carb especially the intake mounting surfaces and heard no change. Since the last soaking and cleaning provided some success I am believing that there might still be restrictions in the carb that a 1 or 2 day soak might help with. Since my neighbor is in no hurry for this I would kind of like to see it through if possible. Especially if you really think a new carb would ultimately take care of the problems. Might as well learn when I can. Please advise me if I may cause damage to the motor. Thanks to everyone for their help.
Jack


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## ossaguy (Dec 3, 2008)

jack13man said:


> After cleaning the carb I re-installed and the motor ran good...throttled up and back to idle really nicely both cold and warm. Then......I mowed.....New problem....after mowning for 30 minutes or so I noticed a little popping and possible backfiring. It would do this both with a load and without. Full throttle and on idle. Am I right in beleiving I still have a carb issue?
> 
> Steve.....I checked the throttle butterfly and everything looks ok to me...thats not saying much is it. I sprayed WD40 all around the carb especially the intake mounting surfaces and heard no change. Since the last soaking and cleaning provided some success I am believing that there might still be restrictions in the carb that a 1 or 2 day soak might help with. Since my neighbor is in no hurry for this I would kind of like to see it through if possible. Especially if you really think a new carb would ultimately take care of the problems. Might as well learn when I can. Please advise me if I may cause damage to the motor. Thanks to everyone for their help.
> Jack


Hi Jack,
I don't know how you could damage the motor.It sounds like you know what you are doing,and I hope your neighbor appreciates it ALOT ! One thing that it seems I hear at every seminar is the instructors warning against soaking a carb in carb cleaner for more than like a half hour.That they say can damage things like check valves,inner o-rings,things like that.We followed Kawasaki's recommendation,and got an Omegasonics ultrasonic tank that really works great for cleaning carbs.The ultrasonic action,in the 140 degree soapy water gets them looking like new inside and out.It's too costly for the home shop I know,but thought I'd point it out.On an expensisve carb like yours,we surely would try cleaning before ordering a new one.So the surging is all gone now? Usually when you get it to run smooth at all rpms,your carb should then be ok,I'd think.The thing that muddies the water a bit on this project is the history it had,where it's been in a shop more than once before for the same problems,so without knowing what they did to it,you are not starting on a clean sheet of paper........If you were to run it longer after it started popping and backfiring,it would be nice to know if it would eventually die,where you could test for spark,or lack of fuel or compression.If it were me,and since you are not on a timetable,I'd do more testing before ordering the expensive carb.

Take care,
Steve


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## jack13man (Apr 28, 2008)

Thanks Steve......I will soak for a half hour or so, blow with air and put it back together. If it starts popping I will just let it run and see what happens. The way it was explained to me was it would run with the choke pulled out part way for about an hour then it would lose power and stumble. I thought that it would be a dirty carb and possibly a coil or ignition module. If I ever got it to start losing the power I was going to check each side for spark. Maybe I just need to let it run longer.Thanks I will let you know what I find.


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## 30yearTech (Sep 14, 2006)

You may want to check the valve lash adjustments on all the valves.

There is also a possibility that there may be an air leak in the intake manifold that develops when the engine gets hot, so you may want to take a look at the O-Ring seals between the manifold and heads.

Best of Luck...


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## jack13man (Apr 28, 2008)

Thanks 30 yr tech....I will check the valve lash tonight......I was out of town all week end so I didn't work on it. Something simple came to me and I will feel foolish if this actually helps but I remember that the gas tank is close to empty now.....I am wondering if there is any water in the tank. Couldn't that cause the popping? Oh well something to look at anyway.......I will drain the tank and refill with fresh fuel also. Again thanks for the help and suggestions. If it continues I will have to check the o rings you mentioned.

Thanks again, 
Jack


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## jack13man (Apr 28, 2008)

Last night I check the valve lash...everything looked good. I went through the carb and cleaned again.(I did not soak) Everything looks brand new. Put back together and it ran fine....no popping. While mowing with it again it ran good....no surging, no popping.But once more it won't idle back down when under no load. I must be missing something in the carb. What do I need to be looking for? If this is the carb, is it sucking air or do you think there is still an obstruction? If you think a new carb would fix these problems I believe that would be the right thing to do. Anyone think it may be something other than the carb? Thanks for your help and any suggestions would be greatly appreciated. 
Thanks again
Jack


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## jack13man (Apr 28, 2008)

One more thing.....after carefully looking at the IPL for the carb I know that I have not ever removed the jets from the carb body. Can you tell me exactly where they are at and if and how to remove them. Thanks


446677
0463-E1
IPL#s 117 and 117A
Thanks Jack


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## hdexpress (May 22, 2009)

*Try the fuel line.*

Check the fuel line from the tank forward. Mine had a similar problem. Replaced the fuel line, it had collapsed inside due to winter gas mix, runs like it is new and not almost 5 years old.


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## Djz020 (May 23, 2009)

yes, it sounds like a definate carb issue. sometimes the rebuild is a b**ch! good-luck!


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## jmccormick (Nov 25, 2002)

Check the fuel cap to see if the vent is clogged.
I had a similar issue with a 422707 and after rebuilding the fuel pump and cleaning the carb and checking the float level the problem was solved.
The engine is leaning out hense the reason you pull the choke and it smoothes out you are basicly reducing the airflow ritchening the mixture.
Also if this application has a fuel pump that could be the reason. Check the pulse tube(line) between the engine and pump if it is not snug on the nipples or has cracks in it replace it. 
I would just go ahead and do the rebuild on the carb fuel pump It is a cheap and easy fix anyway just get a carb fuel pump kit and completely dissasemble carb and fuel pump clean everything and reasemble.


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## 30yearTech (Sep 14, 2006)

jack13man said:


> One more thing.....after carefully looking at the IPL for the carb I know that I have not ever removed the jets from the carb body. Can you tell me exactly where they are at and if and how to remove them. Thanks
> 
> 
> 446677
> ...


The Jet screws into the side of the retaining nut on the fuel solenoid. See the attached illustration.

There is only one main jet that feeds both sides of this carburetor. It's important to make sure both sides are open or fuel will only feed one cylinder and the engine will start and run on the one cylinder, it will be very weak and run rough. Make sure both passage ways in the fuel transfer tube and nozzle are clean and open.

Best of Luck


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## jack13man (Apr 28, 2008)

Thank you 30yearTech.....I know I never took the solenoid apart. Everything else is clean. I am very hopeful that this will help this issue. The only issue right now is not returning to idle when hot. I will respond back when I can tear it apart again. Thanks again...


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## jack13man (Apr 28, 2008)

30 year tech.....I removed the carb, dropped the bowl and all that was holding the solenoid was a small nut. A plastic caplike device was next in line. There was nothing resembling the picture you sent. Is it possible that something is missing or are there several models? The only continuing problem is the not idling back. Thanks again for the help.


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## 30yearTech (Sep 14, 2006)

I don't think the jet is causing your issue. I would look at the governor adjustment or possibly the governor springs are not hooked up properly. You may also want to look at the idle stop screw and make sure it's not set for too high an idle speed.


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## jack13man (Apr 28, 2008)

I will check the governor adjustment.....the idle screw has not been moved and this will idle down when cold and when under a load. I can read back through other post where you have given intructions for a governor adjustment. Thanks again....will let you know...


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## jack13man (Apr 28, 2008)

I just wanted to clarify 1 thing.....when I say it doesn't return to idle I am talking about the RPMS only. The throttle lever returns to the idle adjustment screw just fine.....the motor just doesn't idle back. When cold or under a load it will idle ok.....after warming up the RPMs drop only slightly. Thanks again.


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## jack13man (Apr 28, 2008)

FINALLY...SUCCESS.....I'm not quite sure what did it. I put everything back together. went ahead and slightly adjusted the idle stop(basically moved out and turned right back in) Ran and sprayed around all mating surfaces,found no leaks . After mowing for about 40 minutes it would still idle back like it should. 

Called my neighbor and had him pick it up. Time to put this thread to rest. All of you that put up with this and helped have my upmost appreciation.

1 last thing. I noticed that the voltage gauge would still spike up and down as it ran. Being that it was running pretty good we decided to let things be. Now off to other projects. THANKS AGAIN FOR ALL THE HELP.

Jack


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## light mechanic (Jul 18, 2008)

I am glad for you, there was nothing lost in the experience only gain, us that have learned have learned by trial and fire and still learning each day about the time you think that you are good one of the engines, lawn mower, chainsaw or string trimmer one will bring you back to reality of you must have over looked something, have fun and learn, look forward to the challenge, Light Mechanic


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