[AT] OT - JD STX38 fuel problems

Mike S Meulenberg msm10301 at juno.com
Thu May 20 15:08:52 PDT 2004 

I can try an OEM filter, but I bet it comes off the same line as my NAPA
filter. I'm curious if the original filter was more of a screen versus a
paper element. Phil, I tried vertical and horizontal, no change. I'll
keep monkeying with it. Thanks everyone for all the help
Regards,
Mike

On Thu, 20 May 2004 09:48:08 -0500 "Larry D. Goss"
<rlgoss at evansville.net> writes:
> What you've described here sounds like a typical vapor pressure 
> problem,
> Mike.  Greg's suggestion about a different brand of fuel filter may
> solve it.  Changing blends or octane ratings of gasoline may have 
> the
> same effect.  I've never been able to predictably determine when 
> the
> fuel supply system is going to react the way you are describing it.
> When I replace the fuel filter on John Deere equipment, I always use 
> the
> OEM parts, but sometimes the filter fills and other times it 
> doesn't.
> The running condition can change simply because of changes in the
> weather.  When I'm working on a customer's machine, I simply run 
> the
> engine with hood closed and with all the side panels in place until
> everything is up to ordinary operating temperature.  If the engine
> doesn't falter, I ship it back to the owner regardless of whether 
> the
> fuel filter fills while it's running.
> 
> Remember the good old days of vapor lock?
> 
> Larry
> 
> -----Original Message-----
> From: at-bounces at lists.antique-tractor.com
> [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Mike S
> Meulenberg
> Sent: Wednesday, May 19, 2004 10:42 PM
> To: at at lists.antique-tractor.com
> Subject: Re: [AT] OT - JD STX38 fuel problems
> 
> I mowed again tonight, and here's what I observed:
> 1. When I last left the mower the filter was empty and the shutoff 
> was
> open, when I looked tonight
>      the filter was full.
> 2. After mowing for a while the filter was empty, but it didn't 
> quit.
> 3. About 3 hours after mowing the filter was again full.
> 
> 
> I'm beginning  to wonder if the fuel filter is providing too much
> resistance to flow for a little mower without a fuel pump. Maybe 
> the
> paper cartridge is too restrictive. I will check the carb again to 
> look
> for any signs of the float sticking.
> 
> Thanks,
> Mike
> 
> 
> On Tue, 18 May 2004 21:28:14 -0700 "Dean VP" <deanvp at att.net> 
> writes:
> > Mike:
> > 
> > Another thought. Is it possible that the float is hanging up in 
> the 
> > bowl
> > because it has been bent accidentally to one side? Or the needle 
> > getting
> > stuck in the seat occasionally? Or the float isn't set quite right 
> 
> > to allow
> > enough needle travel? Maybe due to heat?
> > 
> > Can you get to the hose that runs from the in-line filter to the 
> > carburetor?
> > If you take this connection loose at the carburetor is the flow 
> > always good?
> > 
> > 
> > This is the demarcation line. If the flow isn't good at the end of 
> 
> > the hose
> > that connects to the carburetor then the problem is further back 
> > towards the
> > in-line filter and/or tank or lines. If the flow is good, then the 
> 
> > problem
> > is in the carburetor. The parts list doesn't show how the hose 
> > connects to
> > the carburetor, but maybe there is some crud at the inlet point, 
> > maybe a
> > partially plugged screen or sticking float or needle valve. All it 
> 
> > would
> > take is a small piece of crud at the needle and seat to cause the 
> 
> > symptoms
> > you are experiencing. 
> > 
> > I keep thinking of a vapor lock but I've not seen that when one 
> has 
> > rubber
> > hoses feeding the gas. 
> > 
> > Since you don't have the solenoid that shuts off the gas and you 
> are 
> > not
> > losing fuel into the carburetor when the tractor is parked, then 
> the 
> > needle
> > must always be shutting off the fuel flow properly. That kind of 
> > precludes
> > the possibility of some crud at the needle to seat interface and 
> it 
> > would
> > flood occasionally too. Unless you are always shutting off the 
> fuel 
> > valve
> > after each usage. 
> > 
> > To me checking the hose inlet to the carburetor will lead you to 
> the
> > problem.
> > 
> > Dean A. Van Peursem
> > Snohomish, WA 98290
> > 
> > What people can dream, people can do! George W. Bush
> > 
> > www.deerelegacy.com
> > 
> > http://members.cox.net/classicweb/email.htm
> > 
> > 
> > 
> > 
> > -----Original Message-----
> > From: at-bounces at lists.antique-tractor.com
> > [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Dean 
> VP
> > Sent: Tuesday, May 18, 2004 9:58 AM
> > To: 'Antique tractor email discussion group'
> > Subject: RE: [AT] OT - JD STX38 fuel problems
> > 
> > Vaughn:
> > 
> > Seems to me it has everything to do with fuel flow if it is not 
> > working
> > properly. If the wiring is intermittent or the coil in the 
> solenoid 
> > has some
> > windings that short out it may not be opening properly or staying 
> 
> > open
> > properly during run time. It appears to be opened by turning on 
> the 
> > switch
> > and is supposed to stay open until the switch is turned off. If it 
> 
> > isn't
> > opening properly or is intermittent it would explain the symptoms 
> 
> > present.
> > It may start acting up only after running for awhile as it heats 
> up. 
> > 
> > 
> > Dean A. Van Peursem
> > Snohomish, WA 98290
> > 
> > What people can dream, people can do! George W. Bush
> > 
> > www.deerelegacy.com
> > 
> > http://members.cox.net/classicweb/email.htm
> > 
> > 
> > 
> > 
> > -----Original Message-----
> > From: at-bounces at lists.antique-tractor.com
> > [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Vaughn 
> 
> > Miller
> > Sent: Tuesday, May 18, 2004 4:50 AM
> > To: at at lists.antique-tractor.com
> > Subject: RE: [AT] OT - JD STX38 fuel problems
> > 
> > The solenoid at the Carburetor bowl shuts off fuel to the main jet 
> 
> > to
> > prevent backfire, and will have nothing to do with the flow into 
> the
> > carburetor.
> > 
> > Vaughn
> > 
> > >>> deanvp at att.net 5/18/04 1:21:01 AM >>>
> > <snip>
> > 4.) What does the solenoid do in the carburetor bowl? Does this 
> just 
> > let
> > fuel flow when the switch is on? Doesn't look like a pump. Is 
> this
> > solenoid
> > acting up? Wiring loose or corroded? This may be where the problem 
> 
> > is. Is
> > the carburetor bowl clean inside? 
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