[Mgs] Back on track (Part 2 - fuel starvation)

[Max Heim]

But it could be not delivering its full rated flow. Mine was failing to keep
a stock 1798 supplied at 3500rpm.

You don't have to run the engine at 5000rpm to check fuel flow. The pump
isn't RPM sensitive. Just disconnect the fuel line and aim it into a bucket,
turn the key, and check your watch. I don't remember the exact spec volume,
but it should deliver at least a pint per minute.

Mine was shutting itself off after about 6 ounces or 20 seconds, which was a
"fail".

--

Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires


on 4/7/10 12:15 PM, Paul Root at ptrmgb at gmail.com wrote:

> What is the head configuration and carbs?
> 
> Even with better breathing, I don't think the pump would run out of fuel for 1
> 1/2" carbs.
> If you have a DCOE, then maybe.
> 
> On Apr 7, 2010, at 1:10 PM, Eric Erickson wrote:
> 
>> Following on from my previous post, this video shows me up against a
> slightly
>> more modern, more powerful MG -  and not doing such a bad job (although
>> modifying my lines like I thought I could outgun him out of the corners was
>> not real smart).
>> 
>> BUT my biggest issue that day came with the engine running out of fuel at
>> critical moments.  Stuttering and stumbling (yes, I have annotated the
> video
>> to point out the obvious) in both third and fourth gear after a couple of
>> laps.
>> 
>> When I got off the track and popped the bonnet I immediately saw that the
>> fuel-filter was empty.  I pulled off the fuel line and started up the
> pump...
>> and it pumped fuel.  There was plenty of fuel in the tank (in fact, thinking
> I
>> was low on fuel, I slightly over-filled it and it did exactly the same
>> thing).
>> 
>> There were two possibilities that came to mind (you may have others).
>> 
>> 1.  It was hot day (made worse by humidity) at 33C/91F+ - so I was thinking
>> vapourisation/vapour-lock, but I have run in hotter weather and never
> suffered
>> this issue before.
>> 
>> 2.  This engine is bigger than it has ever been at 1950cc with the same SU
>> fuel pump as when she was 1840cc - could I need a higher capacity fuel
> pump?
>> 
>> Any thoughts?  How should I be measuring fuel flow at 5000+ revs (which is
>> when she stuttered and stumbled)?
>> 
>> And the video.....
>> 
>> http://www.youtube.com/watch?v=L5w47B6QN4Q
>> 
>> 
>> Thoughts?