[Fot] TR4 spitting thru Webers - haaaalp!

J.C. Hassall jhassall at gmail.com
Mon Aug 24 15:13:07 MDT 2015


Many thanks to all who responded.  I should have mentioned that the engine
runs like gang busters then spits at apparently random times (irrespective
of throttle).  I did receive some great ideas, tnx.  The points are new
(replaced the XR3000 as a test), all grounds are common at the starter and
the valves are all set to spec. TDC is bang on and cam timed properly (I
was really AR about that!).

I'm going to pull the header and install 2 O2 sensor bungs.  Installing the
AFR sensor in the collector was a mistake (I assumed both carbs would be
the same, but now I need to determine if one of 'em is a problem).  Then
I'll start implementing the suggestions.

Tnx again to everyone who responded.  I will post the results when it's
running as intended.

jim

On Sun, Aug 23, 2015 at 8:14 PM, J.C. Hassall <jhassall at gmail.com> wrote:

> My TR4 spits thru the 40DCOEs at idle and speed.  Timing is set to 32
> degrees at 3K RPM, so idle is about 12 degrees.  I thought that spitting
> thru the carbs meant too much advance, but I believe timing is ok.
>
> The AFR (sensor is in the 4-1 collector - bad idea) at idle jumps between
> 13.8 and 15.3 (seems like an enormous swing!).  Spitting doesn't seem to
> coincide with any specific AFR.  The carbs have been synched, etc.  34
> chokes, 50F9 idle jets, mains are 120 with 200 air correctors.  The mains
> seem awfully small.  Even so, the AFR at speed is 12.8-13.5.  Plugs are NGK
> BP6HS, which are sooty; the ground lug burns clean about half way.
>
> What am I doing wrong???  I'm at the end of my wit (you're right Craig,
> it's a very short walk)
>
> tnx
>
> jim
>
> 63 TR4 in autox prep, 99.5% finished, 90% to go
>
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