• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Fuel Spark...still won't start ?

Share this page

G

Garrett

Freshman Member
Offline
I just bought a 69 sprite, the car hadn't been running for about a year or so. I've gone through and checked the timing, points, put new fuel into it, and the typical stuff. It has Spark and the fuel pump delivers fuel to the carb. It will fire with starting fluid and run on the starting fluid until it its gone. The car won't stay running on its own though. Any input would be welcome, What have other people run into? I'm not terribly familiar with the SU setup could the carbs be gummed up after a year? When I disconnect the fuel line at the Carb the fuel comes out in a constant stream but not with a great deal of pressure? Thanks
 
Garret, it sounds as though the needle valves may be stuck shut. Try to blow through the inlet fittings on the carbs. Or, try spraying some carb cleaner in there. If that doesn't work, remove the float bowl covers and investigate from that end. They could certainly be gummed shut after a year of sitting.
Jeff
 
Should not be a lot of pressure on the fuel line.

Pull the tops off the float bowls and make sure all is clean and that the needles are not stuck. Reasemble and run pump to fill them.

Pop the pistons in the carbs, do they indeed move up and dowb and not stick.

Pull the choke while watching inside the carb, got fuel now?

Should have.

Run it.
 
BTW,
Welcome. I see you made it over from the spritespot.
 
Thanks alot for all the help. I've been checking out a few of the forums. There's a really good community for these cars, which is great to see. When I move the pistons up and down they move freely but do have a little resistance in the upward direction. Is that normal, I assumed it was the just the weight of the piston? Also how far down should the pistons be mine appear to almost completely cover the opening in the carb? Thanks
 
WIth the engine off, the pistons should nearly completely block the inlet throat. The resistance you feel is normal, as you are pushing against both the hydraulic damper and a lightweight spring. Have you checked the float nedles yet?
Jeff
 
They sound about right. (They are spring loaded.) These pistons move up and down as air intake velocity varies. Attached to the bottom is the metering needle. So when the throttle plates open and the air intake increases the pisons pull the needles (tapered) out of the jets and allow more fuel intake. Simple.

I too would start by cleaning out the float bowls and check that the valves are not stuck or clogged.
 
As it's been said, I'd go for the float valves first. Mine, after being stored a winter, stuck once. All it took was removing the cap on the float and it broke loose and functioned perfectly again.
 
I'll be able to disassemble and clean out the float bowls tomorrow. Hopefully that solves it, I don't see how much else could be wrong. It's good to know about those pistons I was a little curious how they worked. I'll keep you updated, I'm sure I'll find something else. Another question as I learn the car though. On the dash there are two lights a red one and a green or blue one (it's a little faded). I haven't figured out what the green/blue one is for yet? Is this the high beam indicator?
 
Blue is high beam indicator.
The red is the charge/ignition light.
 
Which carbs were on a '69, are they HS2s? While you're working on the float and needle valve adjustments suggested there's one other thing to consider since the car was parked for at least a year.

Buy a can of spray carb cleaner. Remove the vacuum chamber and piston with the metering needle. Clean the needle thoroughly of all debris and gunk. The next step requires care. Take a pipe cleaner and make SURE the internal wire doesn't have a sharp burr sticking off the end. Wet the fibers of the pipe cleaner with carb cleaner AND spray some of the cleaner down the jet tube in the carb body. Now use the pipe cleaner to gently remove any gunk in the jet tube (the brass portion... not the plastic hose). Follow this with more spray cleaner down through the jet tube. Finally blow through the tube with low pressure air.

The longer old gas sits in the carb the greater chance you have that gunk will build up in the brass jet tube and on the needle. This seriosly restricts fuel flow and creates a very lean condition. The car may start and barely idle (if you can get it to keep running), but it will backfire and refuse to rev very high when you give it any throttle. Choke may help a bit but it will continue to backfire.
 
Double check the simple things. I had the same issue with Bugsy my '68 Sprite when I brought him home. Would turn over and run on starter fluid but not on his own. Cogitated and cogitated on this one for a week or so. Fuel pump was not ticking and thought I had it figured out as a bad fuel pump. All set to replace and I noticed the battery cables. DPO had transplanted a + Ground 1098 into a - Ground Car. I turned battery around and swapped cables, Bugsy cranked right over and fired up and has been running fine ever since. Other than repolarizing generator, and swapping coil leads I seem to recall, or maybe that isn't necessary, that's all it took. I felt like a friggin genius figuring that one out.
 
Well done, Jim.

Entropy Rule #1: ALWAYS check th' dumb stuff first!

Entropy Rule #2: It's almost ALWAYS the dumb stuff.
 
Hey Thanks alot guys!!! You were right on about the floats being stuck. I cleaned the carbs out yesterday and she fired right up. I had to adjust the idle a little bit but she runs alot better than I had hoped for. Now I just have to wait for that little box in the mail with all my clutch hydraluics and brake stuff and I'll be on the road.
 
Garretts next question-
How do i get this clutch to bleed!!!!!?

better start ur research now ; )
also, a stuck float will
flood ur engine real quick..
hence the "run then quit" syndrome...
my car would go half a mile!
lucky im smart enough to go uphill,
so getting home was no problem..haha...zimmmy
 
Back
Top