Engine runs lean, old Webra 61. Who can help?

[Del Rykert]

Urs.

    Not wanting to spend your money foolishly but I would want to switch out
your pump with a known good working pump from a friend or another source
before buying. Your comment about long period of sitting makes me suspect
something has degraded in the pump. The valve, diaphragm gaskets etc. and a
rebuild if you can get just those parts may be the ticket.
    Reminds me of a Rossi problem I had that wasn't getting enough fuel
until I added a Cline/Kline ?sp pump and engine was a sweetheart after that.
I would try reducing your variables by going to a test stand and get it
running properly on the stand.

    Del
----- Original Message ----- 
From: "ken hendry" <khendry at interhop.net>
To: <discussion at nsrca.org>
Sent: Monday, December 01, 2003 12:05 PM
Subject: Re: Engine runs lean, old Webra 61. Who can help?


| Hi Urs
|     Articles by Clarence Lee in RCM Dec 82 and Robert Munn April 81 about
| lean running Webras with Dynamix carbs confirm Tonys description of the
| metering orfice position and also the problem of the size of fuel passages
| entering the carb- the fuel nipple and following passages. My copy of the
| Lee article has faded but I remember drilling our some of these passages
to
| make the needle allow enough fuel thru to be able to richen the mixture.
| Maybe you know someone who has a good collection of RCM?
| Ken
| ----- Original Message -----
| From: "Urs Baertschiger" <ursbaertschiger at hotmail.com>
| To: <discussion at nsrca.org>
| Sent: Monday, December 01, 2003 4:59 AM
| Subject: Re: Engine runs lean, old Webra 61. Who can help?
|
|
| > Thanks again to all who offered help. - Due to poor weather and
| temperatures
| > below freezing point I didn't do any test runs during the weekend. If
| > weather conditions improve a bit I shall try in the course of this week.
| >
| > Dave: Sorry, forgot to mention that. The pipe was the very first thing I
| > checked and I keep watching it. No clogging, no loose baffle. Compared
it
| > with a almost new Hatori original I can't notice any difference in back
| > pressure.
| > Tank center line is about 1/2" above the needle valve. Hence I didn't
| supply
| > pipe pressure to the tank thinking this wasn't necessary for test runs
on
| > the ground.
| > Lean idling and midrange due to worn brass bar/sleeve are known as you
| > mention it, but so far I never noticed any impact on full throttle.
| > As I disassembled the carb I had checked the fuel metering slot very
| > carefully. It is OK.
| > At present another Dynamix carb is fitted to the engine but, as stated
| > before, the problem is exactly the same.
| >
| >
| > Del: Yes, I think you are right. There is definitely a feeding problem.
I
| > sure do what Tony suggested. A check indicated that the carb was and
still
| > is set up as he said.
| > Fuel lines are of max. diam. I can fit. - You don't sound insulting at
| all.
| > I very much appreciate your comments.
| >
| > Nedim: Thanks, good to know that the combination Dynamix carb and pipe
| > pressure doesn't work. So I am not going to try that again. Also, since
| you
| > experienced pump problems on these engines I certainly will wach and
check
| > the pump as you say. The only thing that amazes me a bit is the fact
that
| in
| > all these years past we never had a failing pump. Hence I'd never
expected
| > the pump to be a problem. But there again, it's been a long time ago and
| > this engine hasn't been run for years in between.
| >
| >
| > Many thanks again and kind regards
| >
| > Urs
| > NSRCA #3069
| >
| > _________________________________________________________________
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