80 tr7 losing power

[FI Spyder]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by john lewis</i>

had wife with me today when i gave car gas and it didnt respond she (wife) stared to choke up from the smell of gas <hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Yes, they are good for that. The smell of gasoline is so foreign to them they can smell it like a DEA canine can smell dope.[:)]



TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

[john lewis]

so i have a carb that is flooding off and on where do i go now

[Hasbeen]

John, when I was having trouble with flooding, it was bad enough for
the thing to be so rich that it would spit sooty bits, out the tail
pipe, but it never stalled the engine.

It would flood when you shut the engine off, badly enough for petrol
to drip out of the carb throat, but it never stalled the engine. For
flooding to stall the engine, it must be pooring in. This makes me
think that either a float is full of fuel, sticking in the pivot
point some how, or the needle of the float valve is sticking/jamming
open some how.

The latter 2 are things I have heard of, but never seen. I thought
they were urban myths. I would also think these problems would be
constant, not intermittent. However, to try to help;

Just what was checked by the bloke who said the carbs were OK?

Did he check the diaphragms?
Did he check there was nothing in, or above the float chamber
needles, which could occasionally jam one open?
If not, check these out.

As a test, remove all the air filter gear, so you can see into the
throat of the carbs, & go for a run. WHEN the thing stops, jump out,
& quickly chech the throat of the carbs.

To be flooding badly enough to stall the thing, petrol would have to
be almost running, not just dripping out of there. If the throat of
at least one carb is not awash with petrol, your problem is NOT
flooding.

Let us know the result. If it is flooding that badly, beg or borrow,
otherwise aquire a fuel pressure gauge, or find a carb shop with
one, & check the fuel pressure, with the thing running. High
pressure is common, when replacement pumps have been fitted, & if
that's the problem, I'll suggest a "FIX".

Hasbeen

PS. Just to clarify, we are talking about the engine cutting out,
while driving down the road, not while idling, aren't we?

H

[nick]

Don't discount electrical. I had a similar problem and chased fuel for some time before I decided to change the coil. $35. It fixed the problem.

nick

[john lewis]

had it in to different carb guy checked pressure 5.5psi both floats work good still seem to leak gas out of bottom canister(absorbation tank)tighen clamp as tight as i could get it seems wet down there do tanks ever go bad little car still works like a new car except the odd time it will not take gas o well til tomorrow

[Hasbeen]

John, that 5.5 PSI fuel pressure is what's causing your problem.
Both the SUs, & Strombergs used on 7s are designed to run with no
more than 2.0 PSI. Your carbs are doing well to contain that
pressure, & have the engine run at all.

I would guess that the car has had a replacement pump fitted at some
time. The replacement pumps available come in only 2 types, designed
to be used with a wide range of cars. The one usually supplied for
TR7s, has a long cam lever, & should come with a couple of phenolic
[plastic] spacers, about an 1/8" & a 1/4" thick.

There are a couple of reasons for these, but mainly, by fitting one
or other of them between the block, & the pump, they adjust the
stroke of this generic pump, to suit the car involved.

By adjusting the stroke, you adjust the pressure at which the pump
supplies fuel to the carbs. Thicker spacer, lower pressure.

I have found that with the pump supplied in Oz, neither spacer is
quite right. The thick spacer is too thick, & reduces the fuel
supply below what's required, where as the thin one still allows the
pressure to be above the 2.0 PSI we require.

I have found that a thin spacer, plus a couple of thicknesses of
gasket made from Corn Flakes packet is ideal, with our SUs. If you
go too far, the thing will start to suffer from fuel starvation at
sustained high revs.

Check with your new carb guy, he probably has a few of these spacers
left over from other jobs, or could make you one, if you explain
what you need.

Alternatively, you can fit a fuel pressure regulator valve, between
the pump, & the carbs, to bring the pressure down. This sounds
ideal, however, I had nothing but trouble with these, when I tried
to do this. To be fair, I was having problems with dirty fuel, at
that time, which prossibly added to trouble.

I have used this "packing the pump out" system on a number of 7s.

The fuel from the canister would be from the flooding carbs
overflowing, & the petrol going to it, as designed. It is probably
full of fuel, if not rusted out. That would also cause problems, so
make sure it'd empty of fuel. Replace the charcoal, if desired. Once
you stop the flooding, by reducing that pressure, that will stop.

Hope this helps.

Hasbeen

[john lewis]

i have a zenith carb would that also only run on 2psi i think ill try the regulator see 1 sold by my canadian suppier in bc hope this works

[Hasbeen]

John, one problem with this wide spread forum, is what we call
things, in our different homes.

I believe you have Zenith Stromberg carbs, but we use different
parts of the name, here, & there.

Yes, the needle & seat of the float chamber of my SUs, & your zenith
carbs are interchangable, probably made by the same people, & work
at the same pressure. I had a US spec 7, at one time, & fitted SU
needle, & seats, when I could not find any needles in Oz in the
right packaging.

Good luck with it. Hope you have better success with the pressure
regulating valve, than I did with the 7. We used to have no trouble
with them on racing cars, even though we were burning a couple of
pints a minute we could still get the pressure down to the 2 PSI the
Webber carbs required, so no reason they should not work.

Hasbeen

[john lewis]

i ordered regulator today increses in .5psi measures should get it by monday hoping fri.but wondering if im doing any damage running it now, put on 60mi(100k) today did it once around 30 mi then worked like a new car for rest of day i put new valve cover gasket on and that stoped leak,got maybe half turn on clamp on rad hose up under motor took a long time i will try again tomorrow looking for a bendable screwdriver but it looks like it helped,cleaned concections on gas tank and got clock working double ground i think changed wires from 1 to the other and my low gas light went out and my gas gauge went all the way to fill but i dont seem to see it going down put 18liters in and gauge was still showing fill well till tomorrow thanks again o yes we are talking about driving along and it stalling not just siting at idle

[Hasbeen]

John, while it's running properly, there should be no damage.

When it floods, you will be putting raw petrol in there, which would
wash the oil off the cylinder walls, & cause rappid wear, if it
didn't stall, or stop flooding, when you down shifted.

It's unlikely, but possible, that you could be getting so much
petrol in there, that you could be diluting the oil. If that did
happen, you should be able to smell the petrol in the oil. This
would be very bad.

It may look funny, if someone should see you, but perhaps you should
smell your dip stick.

Hasbeen

[john lewis]

actually changed oil yesterday no smell or anything else foreign to oil wondering why does it only happen so rarely is the rest of the time she able to use gas being pumped into hercause i notice it would happen when i was coasting not giving her gas most of the time

[Hasbeen]

John, you probably hit a bit of a bump, which helps shake it open
too far, then that high pressure keeps it open.

Then it's only one of your rough as guts down shifts that bounce it
shut. [Just kidding, but I couldn't resist].

The one I had trouble with first was a US spec 7, with
stromberg/zenith carbs. It used to flood, after you shut it down,
from residual pressure in the pump, & lines. With the air cleaner
off, petrol would drip out of the throat of the front carb, after
you shut it down. With that car, it was always the front carb that
was worst.

I don't think the needle jets are as good as they used to be.

I raced a Morgan +4, [Triumph TR3A engine] in the early 60s. We used
to run 2.5 PSI fuel pressure, with the float level set just 50 thou,
[1/20Th of an inch] below the top of the main jet, with no flooding
problems. Of course the SUs then had a copper float, & the float
level could be adjusted just by bending the tang that the needle
worked against. I think those copper floats had more buoyancy, &
applied more pressure to shut the valve.

They don't make them like they used to, [said in a quaver in the
voice, leaning on my walking stick].

After a stop, that US spec 7 would start OK, but would run as if on
3 plugs, for a minute or so, before the excess fuel cleared. It
would then be mostly OK, but it only had a little over 3 PSI
pressure.

Hasbeen.

[PeterTR7V8]

I bet that stick goes well. [:)]


Never say die. At least not while you're still breathing.

[HDRider]

I had a similar problem with one of the 79 DHC's when I first put it back on the road. What was causing the issue was very fine rust particles.

Every now and then they would hang the float needle in the low flow (idle) position so on acceleration it felt like you hit a mattress. Holding the throttle wide open would clear it fairly quickly. The particles would also on occasion hold the float needle open causing fuel runoff into the carbon canister making it overflow onto the ground.

I replaced the fuel filter a few times and the problem lessened with driving. It has not reoccurred at all since I hit 2,000 miles.

Edward Hamer
Petaluma CA

[Hasbeen]

Yes Peter, the fastest walking stick, in the west, & under this West
as well, as it happens.

Hasbeen