[Fot] TR4 with H6 starting problem

[Tim Murphy]

I need some suggestions on a hard starting problem.  The car is a TR4 with
SU H6 carbs.  I have the Kastner G3 cam and the RB needles in the carbs as
recommended by Kas.  The car used to start and idle pretty good.  Then I had
the very worn throttle shafts replaced in winter 2008-2009.  Last summer at
Blackhawk we experienced hard starting due to flooding when starting.  It
starts right up but idles at about 1000 -1500 RPM and the engine wont rev
up until the extra fuel gets run out.  This takes about 30 seconds with the
fuel pump off.  During this time the EGTs are at about 600 indicating very
rich.  Once it gets cleaned out it idles good at 1500  2000 with the EGTs
at 900 to 1000.  I discovered I had the stock SM needles in the carbs,
pushed all the way up in the pistons to give richer running.  I replaced the
SM needles with the correct RB needles and the car started pretty good in
Sept. at Elkhart Lake.  This year in May at Gingerman we started to have the
hard starting problem again.  Discovered another sinking float and replaced
with a good one.  We still had the starting problems where it starts but
wont rev up until it gets cleaned out.  We also had a bit of a stumble
coming out of some of the faster corners.

I replaced the needles and seats thinking it was loading up on some of the
corners.  The old needles and seats were all brass and showed some wear; the
new ones from Moss have the viton tips.  I still have the starting problem
where it wont rev up until it gets cleaned out.  I tried checking the fuel
level in the jet with the pistons and needles out and it seems to be about =
down from the top of the jet.  With the needle in displacing some of the
fuel Im guessing the level would be about at the top of the jet.  Im not
really sure what the best way is to check the fuel level in the jets.  The
floats were set with the SU tool, the oval shaped tube, and I have the 7/16
inch clearance specified, probably within a 32nd of an inch.

Any suggestions of what to check or take a look at and try would be
appreciated.  The problem seems to have started when I had the throttle
shafts redone, closing off the extra air getting into the carbs.  The jets
are both set to about 10 flats down from full up and the EGTs run around
1200 at WOT in 4th down the straights.

I did notice after putting in the new needles and seats and turning on the
fuel pump with the pistons and needles out that I got a pretty good slug of
fuel shot up out of the jets until the floats came up to seal off the flow.



Thanks,

Tim & Ryan

1961 TR4 #317