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Troubleshooting no start issues _UPDATE posted
- Thread starter wbdvt
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poolboy
Yoda
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Re: Troubleshooting no start issues
Must be corrosion. Start spraying with PB Blaster, Kroil, Liquid Wrench, Marvel Mystery Oil, you get the idea.
One other thing that has me puzzled.
You say you see the set screw for the needle carrier. I know that in the larger 175 carbs, that would be impossible as long as the air valve is in the carb. Makes me think, among other things, the air valve is about 90 degrees counterclockwise out of position.
If the 150 carbs are different maybe someone will confirm.
Must be corrosion. Start spraying with PB Blaster, Kroil, Liquid Wrench, Marvel Mystery Oil, you get the idea.
One other thing that has me puzzled.
You say you see the set screw for the needle carrier. I know that in the larger 175 carbs, that would be impossible as long as the air valve is in the carb. Makes me think, among other things, the air valve is about 90 degrees counterclockwise out of position.
If the 150 carbs are different maybe someone will confirm.
SkinnedKnuckles
Jedi Trainee
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Re: Troubleshooting no start issues
Yeah - if you can't remove the piston with the top off either the needle is bent or there's corrosion between the piston and carb body. Now's the time to pull it out and see what you have there.
Yeah - if you can't remove the piston with the top off either the needle is bent or there's corrosion between the piston and carb body. Now's the time to pull it out and see what you have there.
TR3driver
Great Pumpkin - R.I.P
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Re: Troubleshooting no start issues
I think my next step would be to turn the piston so you can remove the needle retaining screw, then use the adjustment tool to unscrew the mixture adjustment all the way. That should let you pull the piston up off the needle carrier, and hopefully get a better view of what is locking the needle into the jet. Maybe even get in there with vice grips to force the needle out.
But it might be wiser to pull the carb off the engine at this point, since you are clearly going to be doing some work on it. And you might even be able to tap the needle out from underneath, once the float bowl etc is out of the way.
Hmm, that would seem to indicate that the needle is locked into the jet somehow and you are only moving the piston against the spring in the needle carrier.wbdvt said:
I think my next step would be to turn the piston so you can remove the needle retaining screw, then use the adjustment tool to unscrew the mixture adjustment all the way. That should let you pull the piston up off the needle carrier, and hopefully get a better view of what is locking the needle into the jet. Maybe even get in there with vice grips to force the needle out.
But it might be wiser to pull the carb off the engine at this point, since you are clearly going to be doing some work on it. And you might even be able to tap the needle out from underneath, once the float bowl etc is out of the way.
Re: Troubleshooting no start issues
Randall,
I did take the carb off the engine once I realized that this was going to be a project. Obviously, this is the source of the start, hard to run and no power issues.
I did order a rebuild kit, needle and tool yesterday from Moss. I was wondering about tapping from the float chamber but will wait until I can unscrew the mixture adjustment all the way out.
Will post my results! Thanks to all!!!
Randall,
I did take the carb off the engine once I realized that this was going to be a project. Obviously, this is the source of the start, hard to run and no power issues.
I did order a rebuild kit, needle and tool yesterday from Moss. I was wondering about tapping from the float chamber but will wait until I can unscrew the mixture adjustment all the way out.
Will post my results! Thanks to all!!!
SkinnedKnuckles
Jedi Trainee
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Re: Troubleshooting no start issues
It can't be bent much, and I wouldn't think it would cause the hang-up your seeing. Just pull the piston straight up & out. Then you can see if corrosion, gum, or whatever is there and clean it up.
When you reinstall, make sure you have the top & bottom marks lined up correctly. These are on the inlet side. The lettering on the carb top will be across the car, as if read perfectly standing up in the passenger seat. Also, tighten the screws in a sequence, and check piston lift when all's done.
It can't be bent much, and I wouldn't think it would cause the hang-up your seeing. Just pull the piston straight up & out. Then you can see if corrosion, gum, or whatever is there and clean it up.
When you reinstall, make sure you have the top & bottom marks lined up correctly. These are on the inlet side. The lettering on the carb top will be across the car, as if read perfectly standing up in the passenger seat. Also, tighten the screws in a sequence, and check piston lift when all's done.
poolboy
Yoda
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Re: Troubleshooting no start issues
In the mean time, go ahead and remove the float chamber, and fill the jet with some of the concoctions I mentioned while the carb is upside down. Hopefully there's enough annular space around the needle for it to break up the corrosion in a few days.
In the mean time, go ahead and remove the float chamber, and fill the jet with some of the concoctions I mentioned while the carb is upside down. Hopefully there's enough annular space around the needle for it to break up the corrosion in a few days.
Re: Troubleshooting no start issues
Okay, here's whgat I did. I took a small allen wrench and put into the jet on top of the needle. A very light rap and the piston popped out. I examined it and didn't see anything, clean off and put back in. Got stuck again and rapped it out.
The needle does wobble around and I would think it would not. Yes? My thoughts are that the wobble would cause it to bind in the jet????
Okay, here's whgat I did. I took a small allen wrench and put into the jet on top of the needle. A very light rap and the piston popped out. I examined it and didn't see anything, clean off and put back in. Got stuck again and rapped it out.
The needle does wobble around and I would think it would not. Yes? My thoughts are that the wobble would cause it to bind in the jet????
TR3driver
Great Pumpkin - R.I.P
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Re: Troubleshooting no start issues
The needle is supposed to wobble a bit, it is actually spring loaded inside the carrier (the part that fits inside the piston). The idea was to remove the requirement for it to be accurately centered in relation to the jet. Earlier carbs had a hard-mounted needle, which if not perfectly centered could cause the needle to rub on the jet enough to upset the mixture (and increase emissions). (Centering the jet is also a PITA)
But the needle is supposed to be slightly smaller diameter than the hole in the jet, so it should not stick. My guess is that the jet is full of fuel deposits. I'm not sure if this would apply in VT, but here in CA the gas we get dries into a hard, white deposit that the usual "carb cleaners" will simply not touch at all. I had a lawnmower where I literally had to chip away the deposit with a dental pick, in order to open up the main jet. Even soaking overnight in Gumout didn't phase it. And several people have had trouble with 'sticky' float valves that seemed to be due to fuel deposits.
But be careful trying to clean in there. The jet is relatively soft brass, and any damage to the bore will screw up the mixture (which is basically controlled by the open area between the needle & jet). And I don't believe the jet is readily available separately nor easily replaced.
Another possibility might be that someone has fitted the wrong needle. The 'big' TRs use .100" jets and corresponding needles, while I believe the Spitfires use .090" jets. But that would be silly, you couldn't start the engine at all ...
The needle is supposed to wobble a bit, it is actually spring loaded inside the carrier (the part that fits inside the piston). The idea was to remove the requirement for it to be accurately centered in relation to the jet. Earlier carbs had a hard-mounted needle, which if not perfectly centered could cause the needle to rub on the jet enough to upset the mixture (and increase emissions). (Centering the jet is also a PITA)
But the needle is supposed to be slightly smaller diameter than the hole in the jet, so it should not stick. My guess is that the jet is full of fuel deposits. I'm not sure if this would apply in VT, but here in CA the gas we get dries into a hard, white deposit that the usual "carb cleaners" will simply not touch at all. I had a lawnmower where I literally had to chip away the deposit with a dental pick, in order to open up the main jet. Even soaking overnight in Gumout didn't phase it. And several people have had trouble with 'sticky' float valves that seemed to be due to fuel deposits.
But be careful trying to clean in there. The jet is relatively soft brass, and any damage to the bore will screw up the mixture (which is basically controlled by the open area between the needle & jet). And I don't believe the jet is readily available separately nor easily replaced.
Another possibility might be that someone has fitted the wrong needle. The 'big' TRs use .100" jets and corresponding needles, while I believe the Spitfires use .090" jets. But that would be silly, you couldn't start the engine at all ...
SkinnedKnuckles
Jedi Trainee
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Re: Troubleshooting no start issues
If you remove the needle from the air valve you can see the number to be sure it's the right one and confirm it's the needle & not the piston that's binding. If it is crud in the jet that's binding the needle, I'd start with acetone and a pipe cleaner. Or borrow some fingernail polish remover from a friend.
If you remove the needle from the air valve you can see the number to be sure it's the right one and confirm it's the needle & not the piston that's binding. If it is crud in the jet that's binding the needle, I'd start with acetone and a pipe cleaner. Or borrow some fingernail polish remover from a friend.
Re: Troubleshooting no start issues
I have examined the needle, still in piston as the adjustment tool, rebuild kit and new needle will arrive tomorrow. I did notice that there is a shoulder on the needle the is outside the piston. should this shoulder be exposed? Could that be larger than the jet?
FYI - I have soaked a pipe cleaned in solvent and inserted in jet to let soak over night to dissolve any varnish.
I have examined the needle, still in piston as the adjustment tool, rebuild kit and new needle will arrive tomorrow. I did notice that there is a shoulder on the needle the is outside the piston. should this shoulder be exposed? Could that be larger than the jet?
FYI - I have soaked a pipe cleaned in solvent and inserted in jet to let soak over night to dissolve any varnish.
eschneider
Jedi Warrior
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Re: Troubleshooting no start issues
Boy, that sticky piston sounds like trouble. maybe I'm not reading closely enough - is it the needle binding, or the piston sticking in the bore, like it was dropped at some point and deformed? Happens more with SU's than Strombergs, but.....
With SU's and Strombergs, I use a mixture of 1 bottle of "aluminum jelly" (mild acidic aluminum cleaner) and about 2-3 qts water. A few hours usually works, but overnight is OK. Rinse thoroughly with water and a stiff toothbrush, and ALL the deposits are gone - carbon, varnish, and white crusties. The post metal is dulled (etched) by the process, but the acid in the solution isn't strong enough to "eat" anything. The surface is dulled a little by the etching effect, but I kind of like it - nice and uniform. Longer soaks tend to stain the brass bits.
I do degrease the carbs first in carb cleaner, but mostly out of habit.
If you don't like this trick, I'm seeing awful lot of guys on craigslist who will ultrasonic clean carbs for $25-40. I've heard some guys use vinegar, but that didn't work as well for me. Tried Coca-cola (contains phosphoric acid) once on a motorcycle carb, and that seemed to work better than carb cleaner (soaked for about a week).
Boy, that sticky piston sounds like trouble. maybe I'm not reading closely enough - is it the needle binding, or the piston sticking in the bore, like it was dropped at some point and deformed? Happens more with SU's than Strombergs, but.....
TR3driver said:
With SU's and Strombergs, I use a mixture of 1 bottle of "aluminum jelly" (mild acidic aluminum cleaner) and about 2-3 qts water. A few hours usually works, but overnight is OK. Rinse thoroughly with water and a stiff toothbrush, and ALL the deposits are gone - carbon, varnish, and white crusties. The post metal is dulled (etched) by the process, but the acid in the solution isn't strong enough to "eat" anything. The surface is dulled a little by the etching effect, but I kind of like it - nice and uniform. Longer soaks tend to stain the brass bits.
I do degrease the carbs first in carb cleaner, but mostly out of habit.
If you don't like this trick, I'm seeing awful lot of guys on craigslist who will ultrasonic clean carbs for $25-40. I've heard some guys use vinegar, but that didn't work as well for me. Tried Coca-cola (contains phosphoric acid) once on a motorcycle carb, and that seemed to work better than carb cleaner (soaked for about a week).
Re: Troubleshooting no start issues
Once I can remove the needle, I will try moving the piston in the bore to see if the problem is there. I will also be able to verify that it is the correct needle as I have ordered a new one.
Overall the carb is pretty clean and I did find a package from a rebuild kit in the trunk, so it has been worked on.
Once I can remove the needle, I will try moving the piston in the bore to see if the problem is there. I will also be able to verify that it is the correct needle as I have ordered a new one.
Overall the carb is pretty clean and I did find a package from a rebuild kit in the trunk, so it has been worked on.
BRSLimited
Jedi Trainee
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Re: Troubleshooting no start issues
Motorcycle shops sell something that you mix with water that does a good job cleaning. I believe I got it from a Yamaha dealer. Though the directions say not to I have found that if you mix this up in an old pot (one your wife won't shoot you for using) and boil the carbs in it for about 15-20 minutes they come out spotless. Just be sure all the rubber parts are out and you do it outside.
Motorcycle shops sell something that you mix with water that does a good job cleaning. I believe I got it from a Yamaha dealer. Though the directions say not to I have found that if you mix this up in an old pot (one your wife won't shoot you for using) and boil the carbs in it for about 15-20 minutes they come out spotless. Just be sure all the rubber parts are out and you do it outside.
Update - Success!!
Just an update - I replaced the needle and cleaned everything. The needle that was installed was a 45L, and I had ordered a 45N. The brass ID tag is missing from the carb, so I went by year 1980 and not a California car, when I ordered it.
The piston moves up and down now and the car started up after the float chamber got filled. Increasing the throttle, I could see the piston move up and down. Under cover of darkness, I did run it down the street last night and there was very noticeable increase in power.
I do still have some tuning to do and there is an issue with the manual choke that was installed. I will do some research on this forum for manual chokes and see I can find my answers prior to posting anything.
It does look like there have been many hands on this carb, to the point where I wonder if I shouldn't find a more complete original ZS CD to start with or an upgrade. The goal really is to have a reliable, fun, convertible sports car that is pleasing to look at and not a late model mass produced item that my wife and I can enjoy the scenic roads of Vermont in.
Just an update - I replaced the needle and cleaned everything. The needle that was installed was a 45L, and I had ordered a 45N. The brass ID tag is missing from the carb, so I went by year 1980 and not a California car, when I ordered it.
The piston moves up and down now and the car started up after the float chamber got filled. Increasing the throttle, I could see the piston move up and down. Under cover of darkness, I did run it down the street last night and there was very noticeable increase in power.
I do still have some tuning to do and there is an issue with the manual choke that was installed. I will do some research on this forum for manual chokes and see I can find my answers prior to posting anything.
It does look like there have been many hands on this carb, to the point where I wonder if I shouldn't find a more complete original ZS CD to start with or an upgrade. The goal really is to have a reliable, fun, convertible sports car that is pleasing to look at and not a late model mass produced item that my wife and I can enjoy the scenic roads of Vermont in.
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Re: Update - Success!!
Congrats!
Good feeling, ain't it? :thumbsup:
Mickey
Congrats!
Good feeling, ain't it? :thumbsup:
Mickey