Fuel/Carburetor Problem

Seeing Scott's pictures of the All British Field Meet in Florida in the Free for All forum this morning inspired me to get the Healey out, take her to run a bunch of errands and go for a ride. Well, on the way home, she sputtered and lost power. I had to keep pumping the accelerator and keep the revs up to keep the engine going. Eventually, the engine died. It took a while, but then it started up again, ran (still poorly) for a bit, died out again, but the car had enough momentum to pull into a school parking lot.

When the engine restarted again, at idle it sounded OK, but when driving around the parking lot it sputtered and wanted to stall if I didn't keep pumping the accelerator to keep the revs up.

I disconnected the fuel line going into the fuel pump and gas was coming out. The fuel pump sounds the same as ever. There is a filter, but it is metal, can't see how dirty. It's been on the car 2 or 3 years, at most 5,000 miles.

My next thought is to go out and bang on the carburetors with a hammer (well, maybe rap firmly)to solve my problem. A friend did that one time when fuel was gushing out of the float chamber, and it worked!

Anybody have any better, perhaps more technical advice for solving this problem before I have the car towed to my mechanic 50 miles away? All due respect to those who have to put their cars away for the winter, but this, and my other recent problem of a non-functioning overdrive is causing me to get a little stressed out, since fall and spring are my favorite time of year to drive the Healey here in southern California...

By the way, great pictures of the All British Meet in Florida, Scott!

Sharon,

From your description I would suspect the carbs are not getting enough gas. A quick check of the float bowls right after it quits would confirm that or not. I had the same thing happen and it was the fuel pump. Replace the filter, thats the cheapest fix and if that dosen't work, check the fuel flow from the pump to the carbs. Where is the metal fuel filter located? If it is in the engine compartment near a source of heat maybe a case of vapor lock? I chased that problem once after putting in a metal cased filter.
Biff

Hi Sharon, Sorry to hear about the patient. Did the engine rev up when you pumped the accelerator? Or did it just remain running? Also , did problem become apparent after warm up? I'm wondering if you have a "sunk-float" (oxymoron?) or a bad needle and seat, and you're getting too much gas.

Hi Biff,

The fuel pump and fuel filter are in the hatch behind the driver's seat. I unscrewed the clamp a bit and a steady stream of fuel came out. Fuel pump is ticking just like usual.

Doug,

When I stepped on the accelerator, the engine rev's went up...

The car was warm when this happened. Had it towed home (sound familiar?) and after it had been sitting, started it - started right up. Don't have enough nerve to hop in and take it around the block to see if it hesitates or not - it's getting late, and it's dark outside!!!

[ 10-20-2002: Message edited by: healeygal ]</p>

Sounds a bit like the carb(s) are out of adjustment a bit and getting too much gas at idle-if it was hot outside, it could exacerbate the problem. Hitting the throttle (in neutral, I assume, to rev it up) clears its throats. Literally. But I'm no expert either.
-Wm.

Hi William,

I'll try hitting the throttle (in neutral, of course) tomorrow. Also, will try changing the fuel filter.

Looking back, I think my Healey is mad at me because I stopped to look at a BJ8 for sale last Friday.

If the car has been sitting for a long time there is another possibility. My car was doing a similar act and I started reving the engine and heard a pop at the rear of the car. When I looked behind the car I found the charred remains of a mouse.
Happy hunting,
SB

As stated above, changing the filter would be a good idea, and a clear one (if available) would be a really good idea. Fuel pump sounds like it’s OK.

Try pulling out the choke a bit (if you haven’t already)and running the car…..if the choke helps, it’s likely to be a fuel delivery problem (running “lean”).

“Lean”: This could indicate that one of carbs has a stuck float or there’s dirt in the float chamber. Also, could be a stuck damper piston (the “slidey thing” which requires you to put oil in the top of the carb occasionally). To check dampers, remove air filters see if dampers move up and down freely with your fingers….also, have someone start car, and observe that dampers move up and down together as engine is revved. Tapping the side of the float chamber (to “unstick” the float) is a good idea, but if it doesn’t help, you may have to remove the fuel lines to the top of the float chamber and remove the three little screws (to remove the top of the float chamber). Clean up the float and the needle and seat (if you’re not familiar with these parts, they work on the same principle as the float and valve in a toilet tank). Some folks prefer to replace the original needle and seat with a “Gross Jet”….I have no experience with them, but others say they’re an improvement over the standard parts. If there’s dirt in the bottom of the float chamber, the main jet and/or the connecting port may be clogged (the small hole in the bottom of the float chamber is the beginning of the connecting port to the main jet). Clean out the float chamber and backflush the main jet/connecting port. To backflush, remove the damper cover (3 more small screws)…..carefully pull straight up, to avoid bending the main jet needle. Apply pressurized spray (such as WD-40) or compressed air (just moderate pressure) to the main jet, so that the dirt blows out of hole in the bottom of the float chamber.

If choke makes things worse, car may be running “rich” already, likely due to a stuck/dirty float chamber needle and seat or a “non-floating” float (or as Doug called it, a “sunk float”). If car runs rich, tailpipe will emit black smoke. Also, you could remove spark plugs…. tips will look black and sooty if car is running rich.

Occasionally, a collapsed muffler (or “mouse clogged”…it happed to me too), can cause poor running.

Don’t forget that worn points can sometimes create similar symptoms. Ditto, coil, wires, cap, rotor. Check (carefully!) to see if car has a decent spark …..and stop looking at strange cars!

Hi Nial,

Didn't have much time today, but a friend stopped by and checked fuel pump flow, which was good, took off fuel filter, but since I didn't buy a new one yet, blew air thru it and replaced it, checked air filters, which look a little dirty, but were cleaned earlier this year, checked oil level in top of carb - added a little oil, tapped on float chambers, pulled out choke (which didn't help or change anything), and went for a ride down the street with the same results as yesterday - have to keep pumping the accelerator to keep the revs up.

Distributor cap and rotor looked OK, plug wires are 3 years old, and no mice in sight. Not enough time to do anything else...to be continued...

Hi Sharon,

As Nial mentioned it could be ignition. The stumble could be an intermittent miss on one of the cylinders which clears with more more revs. Might just be a fouled plug, timing off, bad points, condensor, rotor, wires, ground, points wire, etc, etc. It's very handy to have an spare distributor to change out to see if it is distributor related.

G'luck,
John

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by John Loftus:
Hi Sharon,

Might just be a fouled plug, timing off, bad points, condensor, rotor, wires, ground, points wire, etc, etc.....

G'luck,
John<hr></blockquote>

Hi John,

OK, that's next on the list of things to check - thanks!

By the way, with all this tinkering, tested the overdrive solenoid, which gave out last week. With car in neutral, flipped the switch, moved shift lever to left and right, heard the clicking sound it should be making. Unfortunately, with the fuel/acceleration problem, can't take it out for a test ride...

[ 10-22-2002: Message edited by: healeygal ]</p>

Sharon:

Since everyone is guess...sounds like a contest...what does the winner win?...enough of that...

My guess would have been the filter...and it still could be that...after that...particularily since it seems to work when you pump the acelerator...my next guess is something is wrong with the fuel pump...the great Sherlock Holmes...once said...take all your possibilities away and whaever you are left with...has to be the answer...

The car runs when the gas is pumped into the carbs...but fails when it is not...my guess is the obvious...the pump is not working properly...

There is also the possible conclusion that the old Healey is acting up since you admired a potential replacement...nay...couldn't be...could it?...

Just a comment here on "pumping the gas".....as many of you may know, these cars *don't* actually have accellerator pumps (there's no little nozzle squirting fuel out into the carb bore....these accel pumps are common on American cars and are easily visible when the air filter is removed).

But....when the throttle is cycled up and down (pumped) the carbs are exposed to pulses of vacuum that can draw fuel out of a partly plugged carb...or where the float chambers are low due to a clogged filter or low fuel pressure).

'course it could still be bad ignition....one of my favorite "tricks" to check bad ignition wires (and easy to do) is: Start car when it's dark (away from street lights, etc). "Mist" a spray of water over engine with a plant mister....if sparks start jumping from the wires or coil tower, you may have found your source of weak ignition.

Could still be "revenge" too.

As mentioned, SU carbs have no accelerator pump as such. The function of temporary mixture enrichment when opening the throttle is accomplished by the piston damper on the top of the carb. When the throttle blade is opened, the piston is delayed in rising by the damper. This creates a temporary high vacuum on the jet & causes more fuel to flow. As soon as the piston rises the mixture returns to normal. "Pumping the throttle" will indeed cause a temporary richer mixture.


The amount of piston delay can be adjusted somewhat by selecting a heavier or lighter viscosity oil for the damper. The amount of piston rise can be adjusted by changing the damper springs. Usually the standard 20 wt oil is best for the damper.

One problem that can really cause trouble with idle, & running in general is having a stuck or sluggish piston. The piston does not move up & down correctly in response to throttle settings. This can be caused by dirt in the piston housing, loose or damaged parts or a jet which is not perfectly centered. There are tools & procedures available to center the jet.

D

[ 10-23-2002: Message edited by: Dave Russell ]</p>

Hello all,

Thanks for all the responses and suggestions. Been trying to do as many of them as I can, plus a friend stopped by the other day and did a bunch. I'm inclinded to think carb piston/damper/needle/jet problem - thinking back, it's been sluggish between 2800-3000 rpm going up hills for a while now. The other week, added oil to the damper and it got better; then in a few days, the oil level was down again. But trust me, I'm no mechanic, so we're getting ever so close to calling that AAA flat bed tow truck and heading out to the mechanic.

In the meantime, my computer is giving me trouble - the connection kept dropping off, and it took half an hour to get onto the online today. Henri and Nial may be right - not only is my car mad at me, she's trying to prevent me from finding a solution to the problem!

Nope. Christine was a 57 Plymouth Fury.

ok, you checked float bowl and there is plenty of gas there
next, you checked the carb piston and it slides up and down

Look at points after pulling distributor cap or change them; check gap; look at inside
of distrib cap for cracks, burn marks, anything other than clean.
I previously had a problem with a loose connection at the junction of the capacitor
wire and other wire that attaches to the points, that I noticed while gently opening
and closing the points with a small screwdriver (with the ign on); I got spark at the
points and at the junction alternately.

Visually inspect the coil to distributor wire if you can't swap it out.

Then, pull each plug wire (easier with the engine off) and leaving it setting in position
on the plug (before pushing it down)
Then whilst the engine is running, pull each wire slowly away and back one at a time.
(Try not to lean on the car while doing this to avoid shock. There's a tool made for
this btw.)
You should hear a spark noise at each plug as you do it.
You may be running on only 3 cylinders.

If you have other plug and coil wires to swap out, try a swap, if possible.
You probably received the message about a coil swap, too.

You are very close. no more tows !

Lou

Sharon...how is the car doing?...did you ever figure out what was wrong with the dang carburetor...or is it time to finally upgrade to that BJ7 or BJ8...great driving weather we are having...sorry you are missing it...

Hi Henri,

Lucky for me, in spite of his busy schedule, DougR of the Forum stopped by, checked carburetors, fuel flow, plugs, changed coil - still having a problem. I have all the parts for a tune up, and he is coming back on the weekend, plus he took home the plug wires to "rebuild" them - there are little copper washers that strands of wire are threaded through. Some of them didn't look too good...

I sure appreciate his taking the time to do all this work. He really likes the Hundreds (he even "reconditioned" the overdrive solenoid, but can't test it because the car's not running), so once it's going again, I told him he gets to take it out for a test drive. Now that I've made that statement worldwide on this forum, guess I'll have to keep my word!

Regarding upgrading - I think it was looking at that BJ8 for sale a couple of weeks ago that got me into all this trouble with my Healey - she's mad and decided to let me know, and now I'm missing all the great driving weather we've been having lately!

Have a good vacation in Hawaii! By the way, since you only live a few miles away, I'd be happy to take care of your Healey for you while you're gone.

In what ways do you consider the BJ7 or BJ8 to be an upgrade?

D