Subject: Re: Not there yet (Lannis' Carbs)
Author: Greg Field
Date: Mar 25, 2004, 8:45 AM
Post ID: 1716394956
Lannis:
I have the same engine (950 cc, baffle-free cop mufflers, and so on)
and such and am at basically sea level. I run 40 pilots and 142 mains,
and carburetion is perfect, so I doubt you need larger jets. Despite
the lean jetting, I get between 32 and 40 mpg, but then again, I
usually drive 80-plus mph. I wish mine was as fuel-efficient as Officer
Crump's. What's the secret, Tim?
Did it run this way when you got it? Or did you disassemble the carbs
and clean them before the problem came to light?
First, make sure you're getting a stable flow of fuel. If there is a
restriction in the petcock, fuel line, or needle valve of one or both
carbs, the fuel level in the bowl will gradually drop while the engine
is running, and fill up when it is not. Pull one bowl at a time, and
(holding a catch vessel underneath, lift up on the float to ensure fuel
flows smoothly.
Then, make sure the pilot jets are all the way unrestricted by
build-up. Hold them up to a strong light and look through that tiny
hole. If you're over 40 years old, have one of your kids or someone
with perfect up-close vision look through to make sure the aperture is
free from side-to-side.
If they're all the way clean, pull apart the accel pumps and make sure
you or someone else assembled the plunger and spring right side up. The
flat side of the plunger goes up, and the spring goes under the
plunger. (I assembled one of the two plungers upside-down the first
time I cleaned mine, and the one cylinder ran like you describe because
the check ball in the plunger then blocks most of the fuel flow through
the needle and main jets.)
If you want to, tell me when you'll be doing it and give me your phone
number, and I can call then and talk you through it on the phone.
GF