motor won't run off the choke
Discussion
Wondering if anyone can help me with a problem I'm having with a petrol-powered portable generator.
It has been sitting in my garage for nearly two years since I last ran it - I did put fuel stabiliser in the tank.
Before attempting to fire it up again, I drained all the fuel and refilled it with fresh. I also dropped the old oil and put a new oil filter on it.
The motor starts if I give it full choke and will run OK on half choke, but if I knock the choke off when it's warmed-up, it dies. Also if I hit the idle control switch on half choke , that kills it too.
I took the carb off (Nikki 410) and sloshed it all out with carb cleaner and also checked the operation of the float, float needle and throttle valve assy - all nice, clean and gum-free. Put it back together, but bugger me, it's still acting-up the same. Any ideas why it won't run without the choke?
It has been sitting in my garage for nearly two years since I last ran it - I did put fuel stabiliser in the tank.
Before attempting to fire it up again, I drained all the fuel and refilled it with fresh. I also dropped the old oil and put a new oil filter on it.
The motor starts if I give it full choke and will run OK on half choke, but if I knock the choke off when it's warmed-up, it dies. Also if I hit the idle control switch on half choke , that kills it too.
I took the carb off (Nikki 410) and sloshed it all out with carb cleaner and also checked the operation of the float, float needle and throttle valve assy - all nice, clean and gum-free. Put it back together, but bugger me, it's still acting-up the same. Any ideas why it won't run without the choke?
Thanks for replies - but it's not fuel starvation - it wouldn't run at all if that were the case.
I had the carb in bits and thoroughly wet it with carb cleaner. The float, throttle and idle jets all look good, as do the choke and throttle valves, which is why I'm a bit stumped - it's a really simple carburettor - but it's attached to an engine speed governor - I've no frickin' clue how they work. Could that be the offending item?
This is the recalcitrant little ba$tard...
I had the carb in bits and thoroughly wet it with carb cleaner. The float, throttle and idle jets all look good, as do the choke and throttle valves, which is why I'm a bit stumped - it's a really simple carburettor - but it's attached to an engine speed governor - I've no frickin' clue how they work. Could that be the offending item?
This is the recalcitrant little ba$tard...
If you can't get it going properly I'll buy the tires
The governor opens the main butterfly to give it a bit more oomph when a load is applied. (when revs drop govenor opens butterlfy more).
But I don't think that is your problem. Newer motors have smaller and often non adjustable jets to reduce emmissuions. So if you get a bit of extra air from somewhere/anywhere it can cause them to run even weaker than intended.(and stall). You could spray the carb with WD 40 just as you "off the choke" to see if that delays the stalling. Although it looks in new condition so you shouldn't have leaks around the butterfly spindle.
From the picture it doesn't look as if you have any adjustments at all.
Normally it woulsd be adjust the idle up a bit, then look the main mixture, then the idle mixture. 2 1/2 out as a starting point.
Bear in mind this from someone who cannot adjust his own one...I'm crap with carbs
ETA spring hasn't fallen off the governor? That would do it.
The governor opens the main butterfly to give it a bit more oomph when a load is applied. (when revs drop govenor opens butterlfy more).
But I don't think that is your problem. Newer motors have smaller and often non adjustable jets to reduce emmissuions. So if you get a bit of extra air from somewhere/anywhere it can cause them to run even weaker than intended.(and stall). You could spray the carb with WD 40 just as you "off the choke" to see if that delays the stalling. Although it looks in new condition so you shouldn't have leaks around the butterfly spindle.
From the picture it doesn't look as if you have any adjustments at all.
Normally it woulsd be adjust the idle up a bit, then look the main mixture, then the idle mixture. 2 1/2 out as a starting point.
Bear in mind this from someone who cannot adjust his own one...I'm crap with carbs
ETA spring hasn't fallen off the governor? That would do it.
Edited by jeff m on Saturday 6th March 23:31
Yeah, there are only two gaskets(between carb and inlet tract and between tract and cyl head) - both in good shape. I don't think it's sucking air anywhere it shouldn't be. I tried wafting a cloud of easy-start around it while it was running and it didn't pick the revs up or anything.
I'm going to take the carb apart again today. How big should the hole be in base of the throttle needle seat? The aperture in mine is absolutely tiny - like pin-prick sized, I'm now wondering if that is the problem.....
Ordinarily I wouldn't give to farts about this, but I want to run a fridge/icemaker at the 12 Hours of Sebring in a couple of weeks and warm beer is not an option. Added to which, the ol' ball and chain is nagging me about the approaching hurricane season, which was the main reason for buying it in the first place.
I'm going to take the carb apart again today. How big should the hole be in base of the throttle needle seat? The aperture in mine is absolutely tiny - like pin-prick sized, I'm now wondering if that is the problem.....
Ordinarily I wouldn't give to farts about this, but I want to run a fridge/icemaker at the 12 Hours of Sebring in a couple of weeks and warm beer is not an option. Added to which, the ol' ball and chain is nagging me about the approaching hurricane season, which was the main reason for buying it in the first place.
Lads - look, I'm sorry to be such a pain in the arse - forgive me for taking so much time on this.
Soaking everything in carb cleaner overnight worries me - all the non metallic parts being vaporized and the cleaner evaporating in ten minutes.
Jeff - yes! if I squirt WD-40 into the intake when I knock off the choke, it makes the engine rev and run clean, until it's consumed it and then reverts to crapping out, unless I apply choke again - but what does it all mean, Austin?
Soaking everything in carb cleaner overnight worries me - all the non metallic parts being vaporized and the cleaner evaporating in ten minutes.
Jeff - yes! if I squirt WD-40 into the intake when I knock off the choke, it makes the engine rev and run clean, until it's consumed it and then reverts to crapping out, unless I apply choke again - but what does it all mean, Austin?
Matt Harper said:
Lads - look, I'm sorry to be such a pain in the arse - forgive me for taking so much time on this.
Soaking everything in carb cleaner overnight worries me - all the non metallic parts being vaporized and the cleaner evaporating in ten minutes.
Jeff - yes! if I squirt WD-40 into the intake when I knock off the choke, it makes the engine rev and run clean, until it's consumed it and then reverts to crapping out, unless I apply choke again - but what does it all mean, Austin?
It sounds like your idle jet is blocked hence why it won't idle but only run with some throttle applied. Soaking everything in carb cleaner overnight worries me - all the non metallic parts being vaporized and the cleaner evaporating in ten minutes.
Jeff - yes! if I squirt WD-40 into the intake when I knock off the choke, it makes the engine rev and run clean, until it's consumed it and then reverts to crapping out, unless I apply choke again - but what does it all mean, Austin?
Matt Harper said:
Lads - look, I'm sorry to be such a pain in the arse - forgive me for taking so much time on this.
Soaking everything in carb cleaner overnight worries me - all the non metallic parts being vaporized and the cleaner evaporating in ten minutes.
Jeff - yes! if I squirt WD-40 into the intake when I knock off the choke, it makes the engine rev and run clean, until it's consumed it and then reverts to crapping out, unless I apply choke again - but what does it all mean, Austin?
Matt,Soaking everything in carb cleaner overnight worries me - all the non metallic parts being vaporized and the cleaner evaporating in ten minutes.
Jeff - yes! if I squirt WD-40 into the intake when I knock off the choke, it makes the engine rev and run clean, until it's consumed it and then reverts to crapping out, unless I apply choke again - but what does it all mean, Austin?
Sorry I was not specific re spraying the WD 40. Not into the inlet...more around the carb itself rather like looking for a vac leak on a car.
Soaking everything in a good carb cleaner like B12 Chemtool does require the rubber and fiber bits to be removed but the main jet hole is so small on a modern carb even with soaking it may still need a little physical encouragment.
I would give it a poke with a dental pic, or maybe run a strand of copper wire through while dabbing it with a cotton bud soaked in carb cleaner.
It does sound as if the walls of that hole are varnished by the old gas.
Stabil is reckoned to be good for one year!
PS I would not be concerned about being a pain in the butt, this is for a beer fridge at Sebring...... we have threads about toilets
Anyway this is encouraging me to do mine....
It's dieing because there is too much air for the amount of fuel.
The causes are:
Reading the replies a bit harder
, carb apart, pin/sewing needle down the jets, rebuild.
I'll put a penny on that sorting it.
ETAETA you didn't say if you drained the float bowl before you put it away. If you didn't, my bet goes up to two pennies, maybe three.
The causes are:
- restricted fuel because of blocked jets, or a blocked needle jet, or incorrect fuel level in the float level.
- excess air due to misplaced air filter, crack in inlet manifold, perished seal or similar.
Reading the replies a bit harder
, carb apart, pin/sewing needle down the jets, rebuild.I'll put a penny on that sorting it.
ETAETA you didn't say if you drained the float bowl before you put it away. If you didn't, my bet goes up to two pennies, maybe three.
Edited by bitwrx on Monday 8th March 15:50
Edited by bitwrx on Monday 8th March 15:52
bitwrx said:
It's dieing because there is too much air for the amount of fuel.
The causes are:
Reading the replies a bit harder, carb apart, pin/sewing needle down the jets, rebuild.
I'll put a penny on that sorting it.
ETAETA you didn't say if you drained the float bowl before you put it away. If you didn't, my bet goes up to two pennies, maybe three.
I'm now looking all sheepish and staring at my feet. No - I didn't drain anything the last time I used it - I just shut it off and trundled it into it's dark corner in the garage, I'm ashamed to say.The causes are:
- restricted fuel because of blocked jets, or a blocked needle jet, or incorrect fuel level in the float level.
- excess air due to misplaced air filter, crack in inlet manifold, perished seal or similar.
Reading the replies a bit harder
, carb apart, pin/sewing needle down the jets, rebuild.I'll put a penny on that sorting it.
ETAETA you didn't say if you drained the float bowl before you put it away. If you didn't, my bet goes up to two pennies, maybe three.
Edited by bitwrx on Monday 8th March 15:50
Edited by bitwrx on Monday 8th March 15:52
I'm going to take it apart once more and have a poke around in the idle jet to see if that does anything positive. I'm sincerely grateful to all of you, who have offered suggestions and advice - and as Jeff says, I'm on a mission from God - this think has to be up and running like a swiss watch in time to get our Guinness cold for the Mobil 12 Hours....
Matt Harper said:
I'm now looking all sheepish and staring at my feet. No - I didn't drain anything the last time I used it - I just shut it off and trundled it into it's dark corner in the garage, I'm ashamed to say.
I'm going to take it apart once more and have a poke around in the idle jet to see if that does anything positive. I'm sincerely grateful to all of you, who have offered suggestions and advice - and as Jeff says, I'm on a mission from God - this think has to be up and running like a swiss watch in time to get our Guinness cold for the Mobil 12 Hours....
I only know this may be the problem because I may have done something similar with my trailbike I'm going to take it apart once more and have a poke around in the idle jet to see if that does anything positive. I'm sincerely grateful to all of you, who have offered suggestions and advice - and as Jeff says, I'm on a mission from God - this think has to be up and running like a swiss watch in time to get our Guinness cold for the Mobil 12 Hours....
. Although, in your defence a load of modern stuff doesn't have a fuel tap, so unless you drain the whole tank, you can't acutally drain the float bowl. I had no excuse though; there's a fuel tap, and a natty little drain screw in the bottom of the carb on my bike.Good luck getting it sorted. Very annoying when things don't work the way we want.
Just a note to bring this to a close and a heartfelt thank-you to those who took the trouble to offer suggestions.
It was indeed a narrowing in the idle-jet (wasn't blocked completely, but certainly compromised). The fuel varnish was so hard that carb-cleaner wasn't touching it, but it cleared with a bit of judicious prodding with a straightened-out paper clip. The idle-control needle also has a spring/loaded tail, that interacts with the float, the tail was jammed in the extended position. Freeing this up allowed the needle to move back and forth in the tube - maybe check that out on your snow-blower, Jeff.
Thanks again - warm beer crisis averted.
It was indeed a narrowing in the idle-jet (wasn't blocked completely, but certainly compromised). The fuel varnish was so hard that carb-cleaner wasn't touching it, but it cleared with a bit of judicious prodding with a straightened-out paper clip. The idle-control needle also has a spring/loaded tail, that interacts with the float, the tail was jammed in the extended position. Freeing this up allowed the needle to move back and forth in the tube - maybe check that out on your snow-blower, Jeff.
Thanks again - warm beer crisis averted.
Good day and thanks for advice with regards carb problem for the Briggs and Stratton 5hp powered Mountfield rotovator. I stripped carb down, checked all fuel runs were clear, pulse fuel pump membrane functional, removed and sprayed clean main jet and jet seat orifices (were the main running port was fouled). Cleaned fuel tank and reassembled. Started on choke, fine , pushed in choke, excellent result.
Thanks for the forums advice.
I will try to add detailed images.
Best regards
Phil
Thanks for the forums advice.
I will try to add detailed images.
Best regards
Phil
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