Subject: [TR] Fuel pump gone crazy

From: Bud Rolofson <[email-masked]>
Date: Fri, 25 Feb 2022 09:38:21 -0700

Listerati,

What could happen to make my Spitfire mechanical fuel pump start pumping excessive fuel pressure? I tried two different vacuum gages inline to the fuel line between the pump and the carbs and they both showed over 10 psi (maxed the gage actually). That overwhelms the float needle valves and makes the carbs flood making the engine barely idle and die if I try to increase the rpm’s.

I guess I don’t know enough about how fuel pumps limit fuel pressure internally. Is there something internal to the pump that could fail? Maybe one of the round valves?

I also tried inline fuel pressure regulators (three different ones) but it didn’t seem to faze the high pressure. That was puzzling also.

Once it warms up a little I’ll try a spare pump.

Thanks
Bud

Sent from my Commodore 64
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From: [email-masked]
Date: Fri, 25 Feb 2022 17:55:13 +0000 (UTC)

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the pump only 'spring loads' fuel to the carbs as needed.I don't think the =
spring even generates 10 lbs of pressure when completely flattened out (com=
pressed flat).
something else mechanical is going on if indeed your readings are correct.p=
tegler

-----Original Message-----
From: Bud Rolofson <[email-masked]>
To: Triumphs <[email-masked]>
Sent: Fri, Feb 25, 2022 11:38 am
Subject: [TR] Fuel pump gone crazy

Listerati,

What could happen to make my Spitfire mechanical fuel pump start pumping ex=
cessive fuel pressure? I tried two different vacuum gages inline to the fue=
l line between the pump and the carbs and they both showed over 10 psi (max=
ed the gage actually). That overwhelms the float needle valves and makes th=
e carbs flood making the engine barely idle and die if I try to increase th=
e rpm=E2=80=99s.

I guess I don=E2=80=99t know enough about how fuel pumps limit fuel pressur=
e internally. Is there something internal to the pump that could fail? Mayb=
e one of the round valves?

I also tried inline fuel pressure regulators (three different ones) but it =
didn=E2=80=99t seem to faze the high pressure. That was puzzling also.

Once it warms up a little I=E2=80=99ll try a spare pump.

Thanks
Bud

Archive: http://www.team.net/pipermail/triumphs  http://www.team.net/archiv=
e

verizon.net

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<div style=3D"color:black;font: 10pt arial;">the pump only 'spring loads' f=
uel to the carbs as needed.
<div>I don't think the spring even generates 10 lbs of pressure when comple=
tely flattened out (compressed flat).</div>

<div><br>
</div>

<div>something else mechanical is going on if indeed your readings are corr=
ect.</div>

<div>ptegler</div>

<div><br>
<br>
<br>

<div style=3D"font-family:arial,helvetica;font-size:10pt;color:black"><font=
 size=3D"2">-----Original Message-----<br>
From: Bud Rolofson &lt;[email-masked]&gt;<br>
To: Triumphs &lt;[email-masked]&gt;<br>
Sent: Fri, Feb 25, 2022 11:38 am<br>
Subject: [TR] Fuel pump gone crazy<br>
<br>

<div dir=3D"ltr"><br>
</div>

<div dir=3D"ltr">Listerati,<br>
</div>

<div dir=3D"ltr"><br>
</div>

<div dir=3D"ltr">What could happen to make my Spitfire mechanical fuel pump=
 start pumping excessive fuel pressure? I tried two different vacuum gages =
inline to the fuel line between the pump and the carbs and they both showed=
 over 10 psi (maxed the gage actually). That overwhelms the float needle va=
lves and makes the carbs flood making the engine barely idle and die if I t=
ry to increase the rpm=E2=80=99s.<br>
</div>

<div dir=3D"ltr"><br>
</div>

<div dir=3D"ltr">I guess I don=E2=80=99t know enough about how fuel pumps l=
imit fuel pressure internally. Is there something internal to the pump that=
 could fail? Maybe one of the round valves?<br>
</div>

<div dir=3D"ltr"><br>
</div>

<div dir=3D"ltr">I also tried inline fuel pressure regulators (three differ=
ent ones) but it didn=E2=80=99t seem to faze the high pressure. That was pu=
zzling also.<br>
</div>

<div dir=3D"ltr"><br>
</div>

<div dir=3D"ltr">Once it warms up a little I=E2=80=99ll try a spare pump.<b=
r>
</div>

<div dir=3D"ltr"><br>
</div>

<div dir=3D"ltr">Thanks<br>
</div>

<div dir=3D"ltr">Bud<br>
</div>

<div dir=3D"ltr"><br>
</div>

<div dir=3D"ltr"><br>
</div>

<div dir=3D"ltr">Sent from my Commodore 64<br>
</div>

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