generator problem >it diesles <LOL
07-06-2005, 05:31 PM
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generator problem >it diesles <LOL
thought this might be the right place to axe for help. i have a generac generator in my 5er and the problem is this... it takes awhile to fire up, 30sec of continuous cranking even after i have primed the fule. when started it runs fine. when i shut her down it acts like an old car that when u shut the key of it keeps fighting to stay on (diesleing) what i have noticed from playing with it that on normal shut down the throttle butterfly inside the carb will open full and i can see gas still being sucked into the engine so i am thinking that it is still hot enough in there to ignite the gas still going in. so i manually , when i shut it down, close the butterfly and seems to work with just a puff of air on the last crank. is the generator actually shutting down correctly or should it close the butterfly instead of opening? ive been trying to figure it out now for a week. changed everything. oil, plug, filter, gas. nothing has helped yet. and i cant figure out y it takes so long to fire up. only when it is cold. and one other thing. it also seems like there is too much compression also because if i go to fire it up and it doesnt start, i will push it again and it will not crank like there is too much force or pressure. i have to wait about 5 min. i think that about covers everything.
07-07-2005, 01:06 PM
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HURA1: That is normal for the butterfly to open on s/d. The governor arm controls the butterfly and so when you kill the ign, the RPM drops and it calls for more fuel/air mixture..
Being that is highly likely an air cooled engine, I would guess your dieseling problem is possibly excessive carbon in the cylinder head, especially if it is a flat-head engine. ONAN recommended that their CCK engines be regularly de-carboned at Xnumber of hours. Some of those engines could get so carboned up that the compression ratio would rise enough that between the glowing carbon and the detonation, they could be hard to shut down. Fortunately, they were pretty easy to de-carbon unless you couldn't get to that back cylinder!
On the hard starting, I'm wondering if you have an electric powered fuel lift pump that is cutting off with the ignition and the dieseling is causing the carb bowl and fuel lines to be sucked dry.
Later, during re-cranking, the genset can pull down the batt volts(especially if the batts are not fully up to snuff) effectively stopping the fuel pump from resupplying fuel to an empty bowl.. Eventually, it gets the job done and pushes enough gasoline into the carb bowl for it to restart.
On my old Onan 5.0CCK, It had a hand-start switch position that turned on only the ign and fuel pump if it had run out of fuel.. This allowed me to re-prime the carb bowl prior to cranking... Sure saved on the batteries (or my arm when having to rope-starting that beast)!...
Check the owners manual for your Generac genset and see if it too requires a periodic head de-carboning.
You may wanna' check and see if it could be running a bit rich, laying down more carbon than normal.
Good Luck
Keith
Being that is highly likely an air cooled engine, I would guess your dieseling problem is possibly excessive carbon in the cylinder head, especially if it is a flat-head engine. ONAN recommended that their CCK engines be regularly de-carboned at Xnumber of hours. Some of those engines could get so carboned up that the compression ratio would rise enough that between the glowing carbon and the detonation, they could be hard to shut down. Fortunately, they were pretty easy to de-carbon unless you couldn't get to that back cylinder!
On the hard starting, I'm wondering if you have an electric powered fuel lift pump that is cutting off with the ignition and the dieseling is causing the carb bowl and fuel lines to be sucked dry.
Later, during re-cranking, the genset can pull down the batt volts(especially if the batts are not fully up to snuff) effectively stopping the fuel pump from resupplying fuel to an empty bowl.. Eventually, it gets the job done and pushes enough gasoline into the carb bowl for it to restart.
On my old Onan 5.0CCK, It had a hand-start switch position that turned on only the ign and fuel pump if it had run out of fuel.. This allowed me to re-prime the carb bowl prior to cranking... Sure saved on the batteries (or my arm when having to rope-starting that beast)!...
Check the owners manual for your Generac genset and see if it too requires a periodic head de-carboning.
You may wanna' check and see if it could be running a bit rich, laying down more carbon than normal.
Good Luck
Keith
07-07-2005, 03:53 PM
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sotexrattler, yes there seems to be a big carbon build up because the airfilter box will have a pretty good amount of it. i can t see anything in the manual on the cleaning of the carbon so i will try to find out how to do that. what are preventative things to do in the future? gas or oil additives? thanx
07-07-2005, 04:58 PM
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Originally posted by HURA1
sotexrattler, yes there seems to be a big carbon build up because the airfilter box will have a pretty good amount of it. i can t see anything in the manual on the cleaning of the carbon so i will try to find out how to do that. what are preventative things to do in the future? gas or oil additives? thanx
sotexrattler, yes there seems to be a big carbon build up because the airfilter box will have a pretty good amount of it. i can t see anything in the manual on the cleaning of the carbon so i will try to find out how to do that. what are preventative things to do in the future? gas or oil additives? thanx
As for preventing further carbon buildup, make sure the carb mixture is set correctly. In addition, you might try putting a full rated load on the genset for an extended while and see if it burns some of the carbon out. After all, they do better when loaded up.
If you can ever get it to S/D cleanly, you can do the old sparkplug color test to see if it is running the right mixture.
What airbox? You've got carbon inside where? Only if they've got EGR or such nonsense on such a small engine...
If it is pumpin' oil and carboning up because of that, you've got other problems...
Also, in my earlier post, I should have said check with the MAINTENANCE/SERVICE manual, as owners manuals nowadays are mostly filled up with product liability warning crap, various cautions and obvious references to gasoline being FLAMMABLE
and High VOLTAGE being dangerous etc, etc...
all in 5 different languages...They just don't include any decent operating/service/troubleshooting info anymore...
Usually a separate Maint/Service/Overhaul manual is available and is highly recommended.
Plus, it's nice to have the exact factory part number you need when you are hunting around via the celphone when you are stuck in the outskirts of Lower Slobovia.
Keith
PS. Have you considered getting a diesel genset? One common fuel.
Unfortunately, listen to some of these guys and they'll have you BOMBing it in no time
K.
07-07-2005, 05:29 PM
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Re: generator problem >it diesles <LOL
Originally posted by HURA1
thought this might be the right place to axe for help. i have a generac generator in my 5er and the problem is this... it takes awhile to fire up, 30sec of continuous cranking even after i have primed the fule. when started it runs fine. when i shut her down it acts like an old car that when u shut the key of it keeps fighting to stay on (diesleing) what i have noticed from playing with it that on normal shut down the throttle butterfly inside the carb will open full and i can see gas still being sucked into the engine so i am thinking that it is still hot enough in there to ignite the gas still going in. so i manually , when i shut it down, close the butterfly and seems to work with just a puff of air on the last crank. is the generator actually shutting down correctly or should it close the butterfly instead of opening? ive been trying to figure it out now for a week. changed everything. oil, plug, filter, gas. nothing has helped yet. and i cant figure out y it takes so long to fire up. only when it is cold. and one other thing. it also seems like there is too much compression also because if i go to fire it up and it doesnt start, i will push it again and it will not crank like there is too much force or pressure. i have to wait about 5 min. i think that about covers everything.
thought this might be the right place to axe for help. i have a generac generator in my 5er and the problem is this... it takes awhile to fire up, 30sec of continuous cranking even after i have primed the fule. when started it runs fine. when i shut her down it acts like an old car that when u shut the key of it keeps fighting to stay on (diesleing) what i have noticed from playing with it that on normal shut down the throttle butterfly inside the carb will open full and i can see gas still being sucked into the engine so i am thinking that it is still hot enough in there to ignite the gas still going in. so i manually , when i shut it down, close the butterfly and seems to work with just a puff of air on the last crank. is the generator actually shutting down correctly or should it close the butterfly instead of opening? ive been trying to figure it out now for a week. changed everything. oil, plug, filter, gas. nothing has helped yet. and i cant figure out y it takes so long to fire up. only when it is cold. and one other thing. it also seems like there is too much compression also because if i go to fire it up and it doesnt start, i will push it again and it will not crank like there is too much force or pressure. i have to wait about 5 min. i think that about covers everything.
Electronic ignition or kettering, how many hours? sounds like you have several issues going on here.
I work on a lot of gensets but usually they are diesels. Check out this site, you will get good information as some of them are factory techs. Have the model number ready, they are the DTR of generators.
Good Luck.
Jim.
http://www.smokstak.com/forum/forumdisplay.php?f=6
07-07-2005, 05:33 PM
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this is strait from the Q&A off generac website: " What about omissions regulations? Do I need to "de-carbonize" the cylinder?
Generac uses overhead valve, industrial engines in its RV generators. They comply with all emissions requirements today. Unlike other generator engines, there is no need to overhaul the engine to remove carbon. "
the air box is directly mounted on the carb. the carb comes off the front side of the engine and the box is mounted to that with the filter horizontal. when i take the cover off to get to the filter, pull the filter out and i can see carbon deposites on the filter its self and a nice build up at the bottom of the filter box. a nice finger swipe worth. as i write the gen is on now with the a/c. i added the good ol fuel cleaner to the gas and sprayed some gumout in the carb while on. im thinking about leavin it run till its out of gas and then do it again. called the local rv shop and said thier gen mech is not in today ( as usual) so im hunting online to see if anyone has posted the same prob. thanx
Generac uses overhead valve, industrial engines in its RV generators. They comply with all emissions requirements today. Unlike other generator engines, there is no need to overhaul the engine to remove carbon. "
the air box is directly mounted on the carb. the carb comes off the front side of the engine and the box is mounted to that with the filter horizontal. when i take the cover off to get to the filter, pull the filter out and i can see carbon deposites on the filter its self and a nice build up at the bottom of the filter box. a nice finger swipe worth. as i write the gen is on now with the a/c. i added the good ol fuel cleaner to the gas and sprayed some gumout in the carb while on. im thinking about leavin it run till its out of gas and then do it again. called the local rv shop and said thier gen mech is not in today ( as usual) so im hunting online to see if anyone has posted the same prob. thanx
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07-08-2005, 05:29 PM
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Jim, COOL genset website!!! I've bookmarked that one... Some of those guys have got some unique and OLD critters being restored..
HURA1, ok on the overhead valve engine...(fairly late model) Yup, ya don't wanna pull the head unless you absolutely have to.
Jim is right. it sounds like you may have several things going on.
Have you looked at the color of the spark plugs? do they look carbon fouled or blistered white?
And the exh pipe, does it look like it belongs to a diesel?(smoked up) If so, you may need to take a look at the mixture adjustment on the carb.
Also, when you go to shut it down, make sure you give it PLENTY time to cool down after removing the load. Shutting it down Hotter'n Hell can make that dieseling condition worse.. Also, if the carb is baked by the engine heat after a hot shutdown, it may boil all the fuel out of the bowl and gas lines making it harder to get started next time...
One other thing to check... If it is a built-in genset, Is the genset getting LOTS of fresh cool air and not recycling any pre-heated cooling air or exhaust gasses?
Many a VW beetle engine suffered from hot air recycling and it REALLY caused lots of similar problems. Dieseling,hard starting,vapor locking,very short lifespan etc...
Just shootin' in the dark...
Keith
HURA1, ok on the overhead valve engine...(fairly late model) Yup, ya don't wanna pull the head unless you absolutely have to.
Jim is right. it sounds like you may have several things going on.
Have you looked at the color of the spark plugs? do they look carbon fouled or blistered white?
And the exh pipe, does it look like it belongs to a diesel?(smoked up) If so, you may need to take a look at the mixture adjustment on the carb.
Also, when you go to shut it down, make sure you give it PLENTY time to cool down after removing the load. Shutting it down Hotter'n Hell can make that dieseling condition worse.. Also, if the carb is baked by the engine heat after a hot shutdown, it may boil all the fuel out of the bowl and gas lines making it harder to get started next time...
One other thing to check... If it is a built-in genset, Is the genset getting LOTS of fresh cool air and not recycling any pre-heated cooling air or exhaust gasses?
Many a VW beetle engine suffered from hot air recycling and it REALLY caused lots of similar problems. Dieseling,hard starting,vapor locking,very short lifespan etc...
Just shootin' in the dark...
Keith
07-08-2005, 08:35 PM
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thanx for all the help guys. the plug looks black. my neighboor said that the idle sounds high but he probably knows as much as me about generators wich is not much. i have pretty much done all that i am qualified to do and that is all the basic service so im gonna have to get her looked at by a mech. i would think it has to be dialed in on the carb or something cause it runs fine when going. thanx again guys for all the help. and Jim, that is a cool site.
07-09-2005, 06:34 AM
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Originally posted by SoTexRattler
Jim, COOL genset website!!! I've bookmarked that one... Some of those guys have got some unique and OLD critters being restored..
HURA1, ok on the overhead valve engine...(fairly late model) Yup, ya don't wanna pull the head unless you absolutely have to.
Jim is right. it sounds like you may have several things going on.
Have you looked at the color of the spark plugs? do they look carbon fouled or blistered white?
And the exh pipe, does it look like it belongs to a diesel?(smoked up) If so, you may need to take a look at the mixture adjustment on the carb.
Also, when you go to shut it down, make sure you give it PLENTY time to cool down after removing the load. Shutting it down Hotter'n Hell can make that dieseling condition worse.. Also, if the carb is baked by the engine heat after a hot shutdown, it may boil all the fuel out of the bowl and gas lines making it harder to get started next time...
One other thing to check... If it is a built-in genset, Is the genset getting LOTS of fresh cool air and not recycling any pre-heated cooling air or exhaust gasses?
Many a VW beetle engine suffered from hot air recycling and it REALLY caused lots of similar problems. Dieseling,hard starting,vapor locking,very short lifespan etc...
Just shootin' in the dark...
Keith
Jim, COOL genset website!!! I've bookmarked that one... Some of those guys have got some unique and OLD critters being restored..
HURA1, ok on the overhead valve engine...(fairly late model) Yup, ya don't wanna pull the head unless you absolutely have to.
Jim is right. it sounds like you may have several things going on.
Have you looked at the color of the spark plugs? do they look carbon fouled or blistered white?
And the exh pipe, does it look like it belongs to a diesel?(smoked up) If so, you may need to take a look at the mixture adjustment on the carb.
Also, when you go to shut it down, make sure you give it PLENTY time to cool down after removing the load. Shutting it down Hotter'n Hell can make that dieseling condition worse.. Also, if the carb is baked by the engine heat after a hot shutdown, it may boil all the fuel out of the bowl and gas lines making it harder to get started next time...
One other thing to check... If it is a built-in genset, Is the genset getting LOTS of fresh cool air and not recycling any pre-heated cooling air or exhaust gasses?
Many a VW beetle engine suffered from hot air recycling and it REALLY caused lots of similar problems. Dieseling,hard starting,vapor locking,very short lifespan etc...
Just shootin' in the dark...
Keith
Hey I don't want all of you to think I am some kind of a techno-geeky type but I have been a member of that site for several years. That is also the kind of work I enjoy. I have several big 200kw diesel gensets I maintain.
Check my gallery and see my little genset.
Jim
07-10-2005, 09:46 AM
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HURA; Yep, at this point it sounds like the best plan. Check around and see who is the recommended RV genset place in your area... Some are rather expensive but should know what's goin' on with your unit. Better than having to buy a new one while on a trip!
Jim; I like your OD genset! Cool toy.... how many KW? Cummins engine?
Keith
Jim; I like your OD genset! Cool toy.... how many KW? Cummins engine?
Keith
07-10-2005, 10:34 AM
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If you want to "de-carbonize" it here is an easy way. I have done this on other gas engines. Pull the air filter/intake system so you can get to the carberator. Start it up and get it warm. Keep it running and squirt water into the carb while NOT letting it stall. The steam helps blow the carbon out. When the brown 'smoke' quits coming out of the exhaust let it run for a couple of min. and you are done.
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