Lawnmower Fires then Dies

All,
Patient is a 2 month old Craftsman with a 4.5 HP Briggs and Straton motor. Gas is fresh, oil is up to full mark. Mower has been working OK. Last used about 1.5 weeks ago.
The mower will fire briefly if the primer dome is pushed. Then it dies after using the gas supplied by the primer push.
I have tried taking the air filter off and have tried loosening the gas cap (one thing at a time) with no change in results.
Seems as though it is not pulling gas after the initial firing. This is a new mower with only one run speed. The carb seems bone simple.
Any ideas where to start?
Douglas
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
could be you have water in the bowl or dirt in the bowl nut orfice
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If this happens, it will do exactly what you are describing.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Do you have a suggestion on how to check for a pin hole? Thanks.
D.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No not really I found it on my sears mower by accident, Thing drove me nuts. Seemed that the primer bulb has a tiny hole in it around the edge where it was connected to the housing. I smeared some some blue permatex and it fised the problem.
LJ

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sure, start at Sears. At two months it is under warranty ad you don't want to tinker with it and void the warranty. Let them figure it out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I called Sears and the "kid" I talked to said that if I brought it in, they would send it out for repairs. Probably take 1.5 to 2 weeks. Before I did that, I wanted to check with the wisdom of the list and see if there was something simple I could check and perhaps avoid the hassle.
D.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 24 Jul 2005 20:00:47 -0500, Douglas Fifield wrote:

Take it in there, and tell them you want a "loaner" to mow your grass with while yours is out for repairs.
By the way, this isn't a "list", it's a newsgroup.
--
If you\'re not on the edge, you\'re taking up too much space.
Linux Registered User #327951
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Float is stuck??? Maybe....
I'd remove the bowl and gumout everything.
Check to make sure that dirty gas isnt clogging up the fuel tank would be good too. Gravity needs to have it flow nice and easy.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 25 Jul 2005 08:24:24 -0700, snipped-for-privacy@gmail.com wrote:

The fuel tank is underneath the carburator. Gravity is not a friend in this case.
D.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Fuel tank is underneath??? What the???
Crappy design then. If thats the case then there has to be some sort of pump to get the gas into the bowl. Sometimes they use a small diaphram pump that works off of crankcase pressure. These do go bad too.
What are you worried about right now if its under warranty then have it taken care of by them ASAP. Then just get back to us and say what the problem is/was
Tom
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
On 25 Jul 2005 17:20:11 -0700, snipped-for-privacy@gmail.com wrote:

Yep.
Not at all.

Atmospheric pressure.

Chain saws are likely to have "diaphragm carburetors", while lawn mowers may have "suction carburetors". The fuel tank bolts directly to the bottom of the carburetor. There is no float or float bowl. Fuel is sucked directly into the venturi through the pickup tube and main metering jet.
What I have seen happen, especially on new mowers, is the pickup tube, which is threaded into the carburetor body, isn't tight, and vibrates off, falling into the tank. This will stop the mower cold, except for running off the primer. You can feel for the tube by sticking your finger through the filler opening. It might be laying in the bottom of the tank, if it came loose.
Also check for water in the fuel. It's hard to see, because the tank probably has no drain. Siphon out the fuel and dry the tank out with compressed air.
The pickup tube sometimes has a check ball that can get gummed up and stuck, but a carburetor isn't likely to gum up in two months.
Some kid didn't turn the mixture screw all the way in, just to be cute, did he? I've seen that before, too.
-----BEGIN PGP SIGNATURE----- Version: PGP 7.1
iQA/AwUBQuWijQIk7T39FC4ZEQIkHQCfQDwAXuWuzAu0ftFtRggedRtWSV0AoOEw R2kpToUMXkqRa9gTpzc8uRF3 =fO5h -----END PGP SIGNATURE-----
--
-john
wide-open at throttle dot info
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 25 Jul 2005 20:37:12 -0700, ~^Johnny^~

UPDATE:
Tried the mower today and it started and ran fine. Only difference between today and two days ago is:
1) passage of time, and
2) temperature and humidity.
Two days ago it was beastly hot and humid. Today, the temps are in the low 70's (F) and the humidity is much lower. Everything else is the same.
Douglas
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Yeah, this happened to me. In my case, the ventri was clogged from the varnishes in the gas. Of course when you choke it and start up, you are basically manually making the rich mix in the carb. So it starts fine and dies in 2 seconds. If you don't use gasoline stabilizer, DO. It prevents gum-up in the venturi. I swear by this now after several weeks of intermitent behavior and crazy starts. I would add this to your gas can, and to the remaining gas in your tank. Consider cleaning your carb if this is recurring. The other thing about humidity could be a leaky electrical connection.. Is the plug new?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 26 Jul 2005 21:26:50 -0500, les wrote:

He said the mower was 2 months old, and the gas was fresh. Do you really think the "ventri" is clogged? Do you think you need stabilizer over the summer when it's used every week?

You're quite the mechanic, huh?
--
If you\'re not on the edge, you\'re taking up too much space.
Linux Registered User #327951
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dan... Sure, I stick to my guns. I had new gas and the venturi was plugged from week to week.Small embuli of crude was contaminating the orifice akin to a cardiac vessel, and resurfaced once the pressure pulled it back into position. I'm offering possible scenarios. I'm not a mechanic, though a doctor sees things from his perspective and is willing to share experiences. Hope you feel better.......
Les

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1

I understand. After all, I'm no doctor; but, if I can overhaul a carburetor, surely I should be able to perform open heart surgery, shouldn't I?
Or should I operate in vein? I can see a car, rotted. ;->
-----BEGIN PGP SIGNATURE----- Version: PGP 7.1
iQA/AwUBQufIIgIk7T39FC4ZEQIhbgCg5vyjZL2uIURHyELzBC7OFm0cAr4AoMfy jgEcil4heBS05tItdInwQvh1 =qP6k -----END PGP SIGNATURE-----
--
-john
wide-open at throttle dot info
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
How does it keep the constant flow coming into the carb with the pulse vacuum of the engine in one of these types of carbs????
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
On 26 Jul 2005 19:55:48 -0700, snipped-for-privacy@gmail.com wrote:

It doesn't need to.
In fuel injected auto engines, for instance, fuel can be sprayed into the intake manifold in extremely short pulses, at idle. It all mixes during induction and comopression.
-----BEGIN PGP SIGNATURE----- Version: PGP 7.1
iQA/AwUBQucIgwIk7T39FC4ZEQJ7SACbBrGlAj+s3s9lNAv/EGMKDtpIpBMAnjoo 24HverQrdKJmY5weJbQZdcHW =gcp2 -----END PGP SIGNATURE-----
--
-john
wide-open at throttle dot info
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.