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Re: [Spridgets] Fuel pump

To: GUY DAY <grday@btinternet.com>, Spridgets List <spridgets@autox.team.net>
Subject: Re: [Spridgets] Fuel pump
From: Michael MacLean via Spridgets <spridgets@autox.team.net>
Date: Tue, 12 Jan 2021 22:57:00 +0000 (UTC)
Delivered-to: mharc@autox.team.net
Delivered-to: spridgets@autox.team.net
References: <CAC3x7jOUh_0j2cy-HhM1Ltsw9pDA48ES4A33QLTZEgTKm4pJ9Q@mail.gmail.com> <432799310.552335.1610337513029@mail.yahoo.com> <345c3000.25ad6.176f1056f19.Webtop.101@btinternet.com> <2056307096.611829.1610362654298@mail.yahoo.com> <64a1210.25ed8.176f158f1b9.Webtop.101@btinternet.com> x64; rv:84.0) Gecko/20100101 Firefox/84.0
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 After a cursory inspection today I found a non SU type electric pump.=C2=
=A0 Looks like a large Facet type, but I can't be sure.=C2=A0 I also found =
that there are no filters anywhere between the tank to the Weber.=C2=A0 I r=
emoved the cylindrical mesh filter in the Weber and it was absolutely clean=
.=C2=A0 So I started it up cold and for the first time right after start it=
 idled a little over 500 rpm.=C2=A0 Usually with the jets (probably wrong o=
nes) in the Weber startups have not been under 1000 rpm at idle in the past=
.=C2=A0 The pump was clicking away as normal.=C2=A0 It has rubber type fuel=
 hose on either side of the pump which should not present a problem.=C2=A0 =
Don't want to, but might have to drop the fuel tank and have a look see.
Mike MacLean

    On Monday, January 11, 2021, 4:08:30 AM PST, GUY DAY <grday@btinternet.=
com> wrote: =20
=20
 #yiv6303893106 p{margin:0;}Hi Mike,
Please let us know what the problem / solution is after your examination. I=
 don't know about any-one else but I would really like to know.




I wouldn't jump towards the blocked pickup if only because at a low speed f=
uel suction should be less than it is on the drive home. I take it you have=
 a standard SU pump mounted in the normal under 'rear seat' position. If yo=
u have that would lean me further towards the fuel vaporization in the pump=
 or pipework leading to it.=20


Best of luck in searching,




Guy R Day



------ Original Message ------
From: "Michael MacLean" <rrengineer.mike@att.net>
To: grday@btinternet.com
Sent: Monday, 11 Jan, 21 At 10:57
Subject: Re: Fuel pump

I think you have the most thoughtful explanation so far. I will be under th=
e car in the next few days and check for a leak in the fuel line or it's pr=
oximity to the exhaust. After it finally started the car ran normally all t=
he way home. I doubt it was the diaphragm. Clogged pickup or vaporized fuel=
 is more likely. Thanks for that.Mike M

Sent from AT&T Yahoo Mail on Android=20
=20
  On Mon, Jan 11, 2021 at 2:37 AM, GUY DAY<grday@btinternet.com> wrote:   M=
ike,



Let us consider this as the problem you experience rather than something at=
 which we can throw random ideas (what is the first thing I do - throw in a=
 random idea!) or past histories of different problems. If you are sat with=
 the engine idling or with minimal use when inching forwards, the pump tick=
ing should slow considerably.

Your wonderful description of the pump 'running furiously' suggests racing =
rather than running fast and that means no liquid fuel is in there. The pum=
p will only race when it has no fuel inside it as the viscosity of the liqu=
id stops it. If it is filling empty carbs or trying to compress a vaporized=
 fuel line forward of the pump it will speed up but not race as there is fu=
el stopping the diaphragms from moving too quickly/racing. If it slowly bui=
lds up to racing it may suggest the fuel level in the pump is lowering as l=
iquid fuel is pumped out and/or that that liquid fuel has stopped getting t=
o the pump.

Possible reason:=20

It can race if the fuel in the pump or the line between tank and pump has v=
aporized - the viscosity of the liquid fuel has gone leaving a gas behind. =
Is the exhaust pipe underneath it? You had a warm up run before you reached=
 the slow moving line, exhaust heat is high. There is no air flow under the=
 car to cool it down, radiated and convected heat is heating up things near=
 to the exhaust - but I am presuming your exhaust runs in the proximity of =
the pump. But I'll bet the slow moving line you were in sheltered you from =
any ground level side drafts to allow cooler air to reach under the car and=
 the pump.=20





Other possible reasons:

Tank side fuel line with a pinhole allowing occasional air to get in. I wou=
ld have thought rather unlikely. A damp patch around the fuel line may be e=
vident.

Filler cap vent blocked. Reasonably common.=20

Filter in tank gets blocked. Has the tank has been relined with with a 'slo=
sh liquid' and filter not kept clear? A build up of original crud may be no=
t enough.

Some pumps have a mesh filter on the pump side of the inlet union.=20

Flexible pipe kinked or blocked. Unlikely as liquid fuel loss is at low spe=
ed.

Split pump diaphragm. Why should it mend as the motor runs at normal speed =
again?=20




What the solution is without have a good 'look at' session I don't know. Th=
at it came in when fuel demand is at its lowest, ie the car isn't moving, c=
ould well be the key clue. Looking at something between the fuel in the tan=
k and the pump is indicated, be it exhaust pipe heat or whatever.....=20




Hope it helps.



Guy R Day

 =20

 =20
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<html><head></head><body><div class=3D"ydpfd65bc6dyahoo-style-wrap" style=
=3D"font-family:times new roman, new york, times, serif;font-size:16px;"><d=
iv id=3D"ydpfd65bc6dyiv6303893106"><div><div class=3D"ydpfd65bc6dyiv6303893=
106ydpeddf9901yahoo-style-wrap" style=3D"font-family:times new roman, new y=
ork, times, serif;font-size:16px;"><div></div>
        <div dir=3D"ltr"><div><div dir=3D"ltr">After a cursory inspection t=
oday I=20
found a non SU type electric pump.&nbsp; Looks like a large Facet type, but=
 I
 can't be sure.&nbsp; I also found that there are no filters anywhere betwe=
en
 the tank to the Weber.&nbsp; I removed the cylindrical mesh filter in the=
=20
Weber and it was absolutely clean.&nbsp; So I started it up cold and for th=
e=20
first time right after start it idled a little over 500 rpm.&nbsp; Usually=
=20
with the jets (probably wrong ones) in the Weber startups have not been=20
under 1000 rpm at idle in the past.&nbsp; The pump was clicking away as=20
normal.&nbsp; It has rubber type fuel hose on either side of the pump which=
=20
should not present a problem.&nbsp; Don't want to, but might have to drop t=
he=20
fuel tank and have a look see.<br clear=3D"none"></div>Mike MacLean</div><d=
iv><br clear=3D"none"></div></div><div><br clear=3D"none"></div>
       =20
        </div></div></div></div><div class=3D"yiv6303893106yqt2571889926" i=
d=3D"yiv6303893106yqt57243"><div class=3D"yiv6303893106yahoo_quoted" id=3D"=
yiv6303893106yahoo_quoted_0614701544">
            <div style=3D"font-family:'Helvetica Neue', Helvetica, Arial, s=
ans-serif;font-size:13px;color:#26282a;">
               =20
                <div>
                    On Monday, January 11, 2021, 4:08:30 AM PST, GUY DAY &l=
t;grday@btinternet.com&gt; wrote:
                </div>
                <div><br clear=3D"none"></div>
                <div><br clear=3D"none"></div>
                <div><div id=3D"yiv6303893106"><div><div class=3D"yiv630389=
3106auto-created-dir-div" style=3D"unicode-bidi:embed;"><style>#yiv63038931=
06  p{margin:0;}</style>Hi Mike,<div><p>Please let us know what the problem=
 / solution is after your examination.  I don't know about any-one else but=
 I would really like to know.</p><p><br clear=3D"none"></p><p>I wouldn't ju=
mp towards the blocked pickup if only because at a low speed fuel suction s=
hould be less than it is on the drive home.   I take it you have a standard=
 SU pump mounted in the normal under 'rear seat' position.  If you have tha=
t would lean me further towards the fuel vaporization in the pump or pipewo=
rk leading to it. </p><div><br clear=3D"none"></div><p>Best of luck in sear=
ching,</p><p><br clear=3D"none"></p><p>Guy R Day</p><blockquote style=3D"ma=
rgin:0 auto;padding:0 2em;border-left:2px solid #00ADE5;white-space:pre-wra=
p;"><br clear=3D"none"><div class=3D"yiv6303893106yqt9444842004" id=3D"yiv6=
303893106yqtfd65412"><br clear=3D"none">------ Original Message ------<br c=
lear=3D"none">From: "Michael MacLean" &lt;rrengineer.mike@att.net&gt;<br cl=
ear=3D"none">To: grday@btinternet.com<br clear=3D"none">Sent: Monday, 11 Ja=
n, 21 At 10:57<br clear=3D"none">Subject: Re: Fuel pump<br clear=3D"none"><=
br clear=3D"none">I think you have the most thoughtful explanation so far. =
 I will be under the car in the next few days and check for a leak in the f=
uel line or it's proximity to the exhaust.  After it finally started the ca=
r ran normally all the way home.  I doubt it was the diaphragm.  Clogged pi=
ckup or vaporized fuel is more likely. Thanks for that.<div id=3D"yiv630389=
3106yMail_cursorElementTracker_1610362627286">Mike M<br clear=3D"none"><br =
clear=3D"none"><div id=3D"yiv6303893106ymail_android_signature"><a rel=3D"n=
ofollow noopener noreferrer" shape=3D"rect" id=3D"yiv6303893106ymail_androi=
d_signature_link" target=3D"_blank" href=3D"https://go.onelink.me/107872968=
?pid=3DInProduct&amp;c=3DGlobal_Internal_YGrowth_AndroidEmailSig__AndroidUs=
ers&amp;af_wl=3Dym&amp;af_sub1=3DInternal&amp;af_sub2=3DGlobal_YGrowth&amp;=
af_sub3=3DEmailSignature">Sent from AT&amp;T Yahoo Mail on Android</a></div=
> <br clear=3D"none"> <blockquote style=3D"margin:0 0 20.0px 0;"> <div styl=
e=3D"font-family:Roboto , sans-serif;color:rgb(109,0,246);"> <div>On Mon, J=
an 11, 2021 at 2:37 AM, GUY DAY</div><div>&lt;<span class=3D"yiv6303893106w=
t_Email">grday@btinternet.com</span><span></span>&gt; wrote:</div> </div> <=
div style=3D"padding:10.0px 0 0 20.0px;margin:10.0px 0 0 0;border-left:1.0p=
x solid rgb(109,0,246);"> <div id=3D"yiv6303893106"><div class=3D"yiv630389=
3106yqt9566648195" id=3D"yiv6303893106yqtfd41674"></div><div><div class=3D"=
yiv6303893106auto-created-dir-div" style=3D"unicode-bidi:embed;"><div class=
=3D"yiv6303893106yqt9566648195" id=3D"yiv6303893106yqtfd91069">Mike,</div><=
div><p><br clear=3D"none"></p><p>Let us consider this as the problem you ex=
perience rather than something at which we can throw random ideas (what is =
the first thing I do - throw in a random idea!) or past histories of differ=
ent problems.  If you are sat with the engine idling or with minimal use wh=
en inching forwards, the pump ticking should slow considerably.</p><div><p>=
<span style=3D"display:inline;">Your wonderful description of the pump 'run=
ning furiously' suggests racing rather than running fast and that means no =
liquid fuel is in there.  </span>The pump will only race when it has no fue=
l inside it as the viscosity of the liquid stops it.  If it is filling empt=
y carbs or trying to compress a vaporized fuel line forward of the pump it =
will speed up but not race as there is fuel stopping the diaphragms from mo=
ving too quickly/racing.  If it slowly builds up to racing it may suggest t=
he fuel level in the pump is lowering as liquid fuel is pumped out and/or t=
hat that liquid fuel<span style=3D"display:inline;"> has stopped getting to=
 the pump.</span></p><p><span style=3D"display:inline;">Possible reason: </=
span></p><p><span style=3D"display:inline;">It can race if the fuel in the =
pump or the line between tank and pump has vaporized  - the viscosity of th=
e liquid fuel has gone leaving a gas behind.  Is the exhaust pipe underneat=
h it?  You had a warm up run before you reached the slow moving line, exhau=
st heat is high.  There is no air flow under the car to cool it down, radia=
ted and convected heat is heating up things near to the exhaust - but I am =
presuming your exhaust runs in the proximity of the pump.  But I'll bet the=
 slow moving line you were in sheltered you from any ground level side draf=
ts to allow cooler air to reach under the car and the pump.  </span><br cle=
ar=3D"none"></p><p><br clear=3D"none"></p><p>Other possible reasons:</p><p>=
Tank side fuel line with a pinhole allowing occasional air to get in.  I wo=
uld have thought rather unlikely.  A damp patch around the fuel line may be=
 evident.</p><p>Filler cap vent blocked.   Reasonably common. </p><p>Filter=
 in tank gets blocked.  Has the tank has been relined with with a 'slosh li=
quid' and filter not kept clear?  A build up of original crud may be not en=
ough.</p><p>Some pumps have a mesh filter on the pump side of the inlet uni=
on. </p><p>Flexible pipe kinked or blocked.  Unlikely as liquid fuel loss i=
s at low speed.</p><p>Split pump diaphragm.  Why should it mend as the moto=
r runs at normal speed again?  </p><p><br clear=3D"none"></p><p>What the so=
lution is without have a good 'look at' session I don't know. That it came =
in when fuel demand is at its lowest, ie the car isn't moving, could well b=
e the key clue.  Looking at something between the fuel in the tank and the =
pump is indicated, be it exhaust pipe heat or whatever.....  </p><p><br cle=
ar=3D"none"></p><blockquote style=3D"margin:0 auto;padding:0 2.0em;border-l=
eft:2.0px solid rgb(0,173,229);"><div id=3D"yiv6303893106yMail_cursorElemen=
tTracker_1610337496895"><div id=3D"yiv6303893106ymail_android_signature">Ho=
pe it helps.</div><p><br clear=3D"none"></p><p>Guy R Day</p></div></blockqu=
ote></div></div></div></div></div> </div> </blockquote></div></div></blockq=
uote></div></div></div></div></div>
            </div>
        </div></div></body></html>
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