Backyard Renegade wrote:
(Backyard Renegade) wrote in message . com...
(Backyard Renegade) wrote in message . com...
(Backyard Renegade) wrote in message . com...
"Steve Lusardi" wrote in message ...
I suggest the fault is the tank, not the motor. The tank is leaking air. The
squeeze ball charges the tank. The overpressure tank then feeds fuel to the
carb. Check your seals, gaskets, hose and hose fittings.
Steve
This confuses me. I have always kept the air valve open on top of the
fill cap for the tank, the pressure is equal to that outside the tank.
The ball has checks in which allow me to build up some kind of
pressure in the engine, I have always assumed that once the engine
starts, it somehow draws fuel from the tank, in line with the check
valves. This could only happen if the engine were somehow sucking fuel
from the tank. In fact when I leave the fill cap vent closed, it sucks
the tank down (red plastic portable tank).
Anyway, I have had a better look this morning and I see that the valve
I refered to below does not have an electrical lead, it is more likely
a vacume lead, maybe some kind of vacume actuated idle control (idle
air bypass)? The choke knob feed directly into this unit which also
has two fuel lines running to the carb, one low, one high, could this
also control idle fuel?
Anyway, to the fuel pump, can someone explain how it works on this
engine, that will help me to find it! Is it vacume, or mechanical, in
the meantime I will be looking today in better light, thanks again,
Scotty, Keep em' coming...
Nevermind... I found the fuel pump. It's that thing with springs,
valves, and diaphrams that sproings apart when you remove the wrong
two screws
Everyone carries this pump, well except this year, called
7 dealers, all out of stock till the end of vacation week, ****.
Anyway, looking at the pump it seems pretty simple, there is an airway
that I imagine leads to the intake, so I guess the diaphram is run by
fluctuations in the intake vacume, makes perfect sense to me. Anyway,
hopefully this is indeed the problem, I can't see anything else right
off hand that would create a fuel or vacume leak anywhere else on the
engine.
Now off to see why the heck the one year old water pump on the 3 horse
merc stopped working... I hate this stuff, I just want to build boats
and go fishin'. Scotty
Well, anyone? Am I right about the intake pressure fluctuations
driving the pump? Looks like it. There is a flame arrest plate in
front of the diapharam, this pretty much confirms my suspicions
especially since it was clean, no backfires. I know they would not
drive the fuel pump with exaust. Anyway, I get the pump on friday, I
will let you know.
Well, it did not work, the fuel pump and plug wires too, cause it
makes sense since I had new plugs and all. Anyway, I am thinking it is
carb now after setting all the other perams'. Anyway, I will keep you
posted even more... Building a big skiff now, I will post some pics
soon.
Scotty
95% chance you have a blocked low speed jet. Has it got a idle mixture
adjustment knob? (dont know that age engine) If so follow the linkage
to the needle,(rod with a point and a screw thread and usually a splined
butt end sticking out), pop the linkage off. Mark the current needle
position (scribe a line on it and the carb body) and unscrew the needle
out the carb body completely *counting turns* (best to count till some
identifiable feature on the shaft comes flush with the end of the hole)
*dont* loose any O rings or seals.
Sqirt spray carb cleaner down the hole, let it sit a little, repeat
untill the fumes get to you or you *know* its clean. *DO NOT* attempt
to clean the jet with anything harder than a stiff nylon bristle
extracted from a brush.
Replace needle counting turns.
Try it. If not reasonable, try backing the needle out 1/2 - 1 1/2 turns
in 1/8 turn steps. (the jet may *still* be pasrtially blocked).
Reinstall linkage in its mid range poisition. Go boating.
P.S.
The fuel pump diaphrams are driven from crankcase pressure ports off two
different cylenders. One works the main diaphram in and out. the other
is on a resovoir chamber that pushes fuel to the carb while the main
daphram is sucking a fresh gulp of fuel. Also possible is a one port
pump that aint so fancy. There is a spec for the height the engine has
to be able to lift the fuel. Its in the service manual.
If the pump is bad, it will not lift fuel reliably at idle. Once you
got it going, test it in a tank with the fuel can on the ground. Should
idle the same as when the bottom of the can is level with the top of the
engine.
Also check for air leaks where the carb mounts to the block. Spray WD40
through the straw that comes with the can round the gasket with the
engine running as slow as you can and see if the revs pick up any. If
so you got a leak.
Got our club Johnson seahorse 20 1973 engine to do the waterpump on
tommorrow. Parts just in. Just had the 18 month old mariner dealer
serviced and they found a fouled carb. Same gas for both so now I
*know* I need a carb kit for the johnson. Probably need new reeds as
well and I allready know the points are out of spec. Oh well, makes a
break from rubbing down Stingo.
--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- &
[dot]=.
*Warning* SPAM TRAP set in header, Use email address in sig. if you must.
'Stingo' Albacore #1554 - 15' Uffa Fox designed, All varnished hot
moulded wooden racing dinghy circa. 1961