From: Yvan on
Nedavno Noddy piše:

> If there isn't, then my advice would be to get the idle running
> satisfactorily on petrol and then adjusting the idle quality with the
> idle mixture screw on the converter (which you'll no doubt have to do
> anyway).


Here is my second attempt at amos ring:

http://www.ptt.yu/korisnici/i/v/ivica/lpg/AmosMK2.jpg


Top is made out of wood. I drilled 38 mm hole, flattened 12 mm aluminum
pipe, and fixed it tin the slot from the left side. I have cut the end
of the pipe at 45 degrees angle.

I than made it air tight by some cardboard and (as before :-), with a
paper sticky tape.

The result: cold start will have to be checked tomorrow morning when
engine cools down, but what a response when I floor it :-) With spud
pipes there was nothing, it had a feeling that it was decelerating, but
now. Wow!

I just hope it starts from cold. Will report in the morning.



--
___ ____
/__/ / \ ** Registrovani korisnik Linuksa #291606 **
/ / \/ /\ \ ** Registered Linux user #291606 **
/__/\____/--\__\ ** http://counter.li.org/ **
From: Noddy on

"Yvan" <me(a)privacy.net> wrote in message
news:5rojgmF15pbaaU1(a)mid.individual.net...

> The result: cold start will have to be checked tomorrow morning when
> engine cools down, but what a response when I floor it :-) With spud
> pipes there was nothing, it had a feeling that it was decelerating, but
> now. Wow!
>
> I just hope it starts from cold. Will report in the morning.

Good job :)

Keep up posted on your progress.

--
Regards,
Noddy.


From: Yvan on
Nedavno Noddy piše:

>> I just hope it starts from cold. Will report in the morning.
>
> Good job :)
>
> Keep up posted on your progress.


I tried this morning, and it would start, but if I lift my foot off the
throttle - it will die :-( It looks like it is too rich, after couple
of minutes it will idle at low ~500 rpm, and I have enough time to go
to the engine and try to adjust lpg idle screw. It is a bit better if I
screw it in two turns. But than I have to slowly unscrew it as engine
warms up or it will die again :-(

Any suggestions?



--
___ ____
/__/ / \ ** Registrovani korisnik Linuksa #291606 **
/ / \/ /\ \ ** Registered Linux user #291606 **
/__/\____/--\__\ ** http://counter.li.org/ **
From: John McKenzie on
Athol wrote:
>
> Yvan <me(a)privacy.net> wrote:
>
> > I tried this morning, and it would start, but if I lift my foot off the
> > throttle - it will die :-( It looks like it is too rich, after couple
> > of minutes it will idle at low ~500 rpm, and I have enough time to go
> > to the engine and try to adjust lpg idle screw. It is a bit better if I
> > screw it in two turns. But than I have to slowly unscrew it as engine
> > warms up or it will die again :-(
>
> > Any suggestions?
>
> For a given throttle opening, the ideal idle mixture gives the highest
> idle speed, which can be measured with either a tacho or, believe it or
> not, a vacuum gauge. The faster the idle, the more the vacuum.
>
> Adjust the idle throttle opening up enough that you can get the engine to
> idle when completely cold. Immediately adjust the gas idle mixture at
> convertor to maximise the idle speed. The trick is to adjust the idle
> speed up by changing the mixture, then adjust the idle throttle opening
> further closed to bring the idle back down then repeat over and over...
>
> Ideally, you should be able to get the gas idle adjusted right so that
> the throttle opening is back to the original petrol position. This needs
> to be done before the engine warms up and alters the gas mixture. If
> it's adjusted right, you should be able to start the engine from dead cold
> and have it idle smoothly right from dead cold. Sometimes, this has to be
> done over several cold starts to get it really right.

If I could just add one little bit here. it's not 'right' exactly, but
often works. Sometimes if you adjust the idle till it's perfect, you'll
find that just past idle, say 5-10mm of pedal opening, the motor is very
rough. In simple terms, the mixer main circuits aren't starting early
enough (possibly because the signal strength is too low, which can of
course be helped by the design of the mixer top plate if necessary).
Once you get past that - say 1-2cm of pedal movement, it's fine again.
In these situations, a trick that can sometimes help is to temporarily
adjust the idle rpm screw about 1/4-1/2 a turn (to open the throttle
into that 'bad' running range) and then turn the idle mixture screw to
clean it up. Often you can then turn the idle speed back down, and it'll
still idle fine. Sometimes it won't idle well, but that 5-10mm range is
perfect. In that case, mark or remember where the best standard rpm idle
mixture was, and where the mixture was for best fast idle (I mean the
faster idle speed as used above, I'm not talking about the fast idle
system/linkages on some petrol carbs, sorry for the double use and
confusing terminology) and adjust the idle mixture screw in the middle
of the two settings. It usually solves that issue if it comes up.

> Sometimes, the above process just doesn't work and the idle opening
> needed for gas is more than for petrol. If you are converting to straight
> gas, this won't matter (you won't actually know) but if you want to
> continue to run petrol, I'd suggest that you install a hand throttle.
> This is a knob on the dash that allows you to screw the idle up a little
> bit. It's common on 4WDs, and simply acts to pull the throttle pedal down
> a bit towards the floor. When the hand throttle is screwed right in, it
> allows the throttle to return to the stop on the carby. There are fancier
> automatic ways of doing it but that's the easiest way.

If you are lucky, sometimes carburettors have a fast idle solenoid on
the linkage - this is sometimes common on air-conditioned cars, to open
the throttle more to get the idle rpm back up with the compressor
running. If yours currently doesn't have it, there might be one for that
carb that exists, so will bolt on easily. By adjusting it so it only
lifts the idle rpm a little (less than the a/c would need) - you can
wire that into the lpg/petrol selector. I know that sounds more
complicated, but if the parts exist for that carb, it'll be an easy fit.


--
John McKenzie

tosspam(a)aol.com abuse(a)yahoo.com abuse(a)hotmail.com abuse(a)earthlink.com
abuse(a)aol.com vice.president(a)whitehouse.gov president(a)whitehouse.gov
sweep.day(a)accc.gov.au uce(a)ftc.gov admin(a)loopback abuse(a)iprimus.com.au
$LOGIN(a)localhost world's #1 sardine whisperer root(a)mailloop.com
$USER@$HOST $LOGNAME(a)localhost -h1024(a)localhost abuse(a)msn.com
abuse(a)federalpolice.gov.au fraudinfo(a)psinet.com abuse(a)asio.gov.au
$USER(a)localhost abuse(a)sprint.com abuse(a)fbi.gov abuse(a)cia.gov
From: Yvan on
I read last two posts, and it sounded that I need more throttle gap at
cold start. So I decided to remove choke flap block - and it seems that
it did the trick.

This afternoon I could start the engine, and it would run from cold.
Only for a short period of time it wants to stall, but it looks to me
that stepped cam is not adequate, I may try to increase fast idle rpm
by screwing in fast idle adjustment screw.

I will test this again tomorrow morning. Hope it finally works :-)

I did the test without air filter and air filter box top cover, so I
will probably have to readjust idle settings when I put finished mixer
plate with air filter in place.



Now I have another question. How does diameter of gas entry opening
influence lpg consumption? I do most of my driving in the city traffic
about 4 km at the time. So I will be driving mostly with only primary
barell open. But I really like acceleration with this 38 mm diameter
opening (effectively its only ~34.5 mm as some area is blocked by pipe
an metal that holds the bolt for air box top cover - not very clear on
the photo from the link).

So I think that I will stay with this diameter. But what effect on fuel
consumption (in the same driving conditions) would have slightly
larger/smaller diameter?

--
___ ____
/__/ / \ ** Registrovani korisnik Linuksa #291606 **
/ / \/ /\ \ ** Registered Linux user #291606 **
/__/\____/--\__\ ** http://counter.li.org/ **