[Tigers] Fuel Pressure Too Low?

James Lindner jliny5 at cox.net
Fri Aug 3 07:02:28 MDT 2012


Hi Listers,

I know the title of the posting is low fuel pressure but as you might 
recall, the larger problem I was having involved the engine stumbling badly 
after driving for 30 minutes or so. Assessment was that the engine, for some 
reason, was being starved for fuel. Heat was a big suspect, as was a 
possible clog in the line somewhere. Ignition was also a possibility. At the 
time of my first post on this subject I had just replaced the fuel pump 
(stock). Just to close things out, I am guardedly optimistic that I might 
have resolved the issue.

Following many recommendations, I was scheduled to blow out the fuel lines 
this weekend to make sure I did not have a clogging problem that was 
starving the engine for fuel after driving awhile. In the meantime, I 
replaced the coil and then moved on to the carb (Holley 1848, 465 cfm) to 
check a few things. Previously, I had installed a phenolic spacer to reduce 
heat soak. I went to adjust the float level but found that I could not 
secure the adjusting screws and nuts and fuel kept leaking from the 
adjustment screws/nuts. At that point, I replaced both needle and seat 
valves and the adjustment nuts, screws and little gaskets. I also noticed a 
slight leak at the seam of the secondary bowl so I replaced the gasket. 
While I had the secondary bowl off I also replaced the little rubber gaskets 
at the ends of the fuel line between the bowls. Once back together I 
adjusted the float levels...they were low.

Yesterday I took it for a test drive. It was 90 degrees and I drove for an 
1h 10m and 57 miles mostly cruising at 50-60 mph. I stopped at 20 miles for 
a quick peek at the carb to make sure it was not leaking. I stopped again 
after about 40 mins to add 2 gal of fuel (I was trying to keep fuel level 
low since I was expecting to drain the tank in prep for blowing out the 
lines.) While cruising, I goosed it a few times and accelerated to 80. At 
the end of the drive I went through town and caught a couple of lights to 
check things in stop and go traffic. The engine never stumbled once.

I also noticed that the idle returned to almost normal (850-900) when the 
engine was hot. Previously, it would stick at 1400-1500 and I could not get 
it to kick down. Today it was a bit fast at 1050 but much better than it 
was.

In the past I also would get a very small puddle of fuel on the intake on 
the driver side of the carb toward the rear. No sign of that.

At the end of the day, I was wondering if it was the carb or the coil. I 
know I could always put the old coil on and test it but I am happy just to 
have things running smoothly.

Thanks to Joe who helped me with the fuel pump and Gene who provided mucho 
advice from afar.

Keeping my fingers crossed...

Jim

-----Original Message----- 
From: RObin Young
Sent: Tuesday, July 24, 2012 9:49 PM
To: tigers at autox.team.net
Subject: Re: [Tigers] Fuel Pressure Too Low?

Jim,  please post the outcome when a solution is found. RObin
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