That is funny. I have the squirt gun set up on my 73 also. it got disconnected
somewhere.

My 73 250 runs 10-11 mpg real consistently, and i climb lots of hills here in
montana. not towing anything, but do carry a motorcycle on the back bumper.

I run a Holley economaster carb. it is a spread bore 450 cfm that is a direct
replacement for the q-Jet.

I noticed a small drop in top end power, but on the hills it seems that the temp
gauge controls my speed more than the cfm limitation.

My 250 has 100K miles on the motor with rebuilt heads and new headers (4-2-1 for
economy) about 9k miles ago. It has a single large muffler that needs to go.
gonna switch to dual exhaust with turbo flow mufflers.

ANYWAY... relative to the sudden small drop in gas mileage...... check the vacum
advance on the ingition. You may not notice whan the advance fails - usually a
slight stumble on acceleration - but it does impact fuel economy in about the
way you describe. When you set timing you unhook the vacum advance. Once you get
it set, leave the timing light hooked up and hook up the vacum advance. the run
the engine, and have some one crack the throttle while you watch the timing
marks. It should jump ahead a considerable distance when the throttle is
cracked. If it does not either the vac advance is hooked up wrong, the hose is
cracked or the diaphragm has failed. While you heve everything hooked up, unhook
the vac advance hose and have your friend bring up the engine rpm gradually to
about 2500. you should see mechanical advance move the timing forward when you
do this. If it does not your mechanical advance has failed. this also impacts
fuel economy but results in a noticable drop in power as well.

Good Luck.

----- Original Message -----
From: Marcus Pizzorno
To: Revcon_Curious@yahoogroups.com
Sent: Wednesday, July 08, 2009 1:58 PM
Subject: [Revcon_Curious] Re: To The Revcon Gearheads...





Thomas:
Either the engine has lost power/efficiency or something is dragging.

Easy Test: Jack up each tire and spin the wheel.
Harder Test: Check the compression. (You really want a baseline at some point
in time anyway.)
Hardest Test: Remove belts and spin water pump, power steering unit,
alternator and check for drag.

GMC folks report 12-14 mpg with a Fuel Injected 455.
Marcus

P.S. Do you still use the squirt gun to cool your rig?!

P.P.S. Try disconnecting the power source to the H2 Gen and see if the lowered
load on the alternator improves mileage.

P.P.P.S. Since you have the squirt gun in place, and since moist air allows
the air to burn slower and more efficiently, have you thought about trickling
moisture into your air intake from the squirt gun?
(For those not in the know, a previous previous owner tapped into the water
supply and put a shut-off valve to misters in front of the radiator to help cool
the rig on long, hot climbs. I call this ingenious device The Squirt Gun!)

--- In Revcon_Curious@yahoogroups.com, thomas wessels <thomwessels@...> wrote:
>
> Dave, Marcus, Gordon... anyone with an idea, I'm pulling my hair out here...
>
> We have flatnose unit #71-0004. 455 Olds. I'm a light foot, 55-60 mph,
towing a Sidekick. I have for 2 years been trying to up the mpg from 8-9. So far
zip.
>
> It still has the Q-jet which was rebuilt and reworked so as to give us the
leanest jetting possible (my carb guy went 3 times to a Smog Station to verify
we were at the best numbers)
>
> We took it 8000 miles last year with the toad and averaged 9 mpg.
>
> Lately the mpg has dropped to 7-8 with the same setup.
>
> We've had the carb tweaked and worked on several times. I don't want to put
any more 'Revcon units' into it, so I am in process of getting a Howell TBI fuel
injection retrofit unit.
>
> I thought maybe the carb is dumping more fuel than it should, causing the
drop in mpg.
>
> Here's the kicker...I looked at the plugs yesterday expecting to see some
black (at least dark) residue from too much fuel - but they all looked evenly
clean and light beige.
>
> To me that indicates that I am NOT running too rich, no?
>
> If that's so, where is my fuel mileage going? I am still getting the new
F.I. system, but I don't think that the carb is necessarily the problem now.
>
> BTW: I even installed a real neat looking and well designed hydrogen
generator after a friend got substantial mpg increase in his p/u and his moho
from 7 to 14 mpg (same engine - Ford 460 in both).
>
> Even with this unit running, I have seen NO improvement. It just seems I am
stuck at about 8 mpg now.
>
> Anybody put F.I. on and see better mpg? Any other stuff I can do?
>
> Thanks
>
> Thom and Kathy
> Revcon 250
> 71-0004
>
> I
>
>
>
>
> [Non-text portions of this message have been removed]
>





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