Les Posted December 31, 2000 Share Posted December 31, 2000 Tom, Sounds like your inlet needle and seat are malfunctioning. Three things commonly cause this. Dirt under the inlet valve, a ring worn in the needle, or distortion in the seat, a leaky float. Occasionally a dimple worn in the float tang where it pushes on the needle. First I would take the carb off and blow backwards through the inlet seat. If you blow from the fuel line in and your carb has the rubber seat you will blow it out. If it has the rubber seat it will have the steel needle. If it has a "Viton" tipped needle it will use the brass seat. If you get a new needle and seat from Briggs it will have the rubber seat and 2 needles. Use as stated above. The rubber seat goes in with the little groove against the brss seat. Start it in and use a Pin Punch and push it down to seat it. If you have the Viton needle , look at it and see if it has a groove or worn ring around it where it sets on the seat. If you can see it, replace it. It may seat part of the time and sometimes it will notbe centered due to the wear area and not seal. Occasionally when your problem occurs and it is due to foreign material, you can pinch the fuel line off with the engine running and run the carb out of gas. The float will drop low enough that when you open the line the flow and larger gap at the needle will flush the culprit out. Remember that when you operate the float by hand you are putting a lot more pressure on the needle than the float does with fuel lifting it, so it may not leak then but will when the float is controlling it. To check for a leaky float, shake it listen for gas, and if you have doubts submerge it in a can of very warm water. If it has a leak the warm water will cause the air inside to expand and you will see a TINY air bubble come out. As cheap as a needle and seat are, I would just replace it and most likely be done with the problem. Good Luck and Happy New Year. Al Link to comment Share on other sites More sharing options...
Yeoman627 Posted December 31, 2000 Author Share Posted December 31, 2000 While clearing snow with my '73 Broadmoor 728 this past weekend (MsgID:2792, Boasting My '738 Broadmoor), there were a few ocassions where, after running for a while, the engine [B&S 191700] would suddenly start running rough and stall. With the engine stalled, I could smell gas and observed gas 'pouring out' of the carburetor. I closed the fuel shut-off valve and looked for anything externally unusual. Not having found anything obvious, I would open the fuel shut-off valve (no fuel leak), started the tractor, and everything is fine. I did remove the fuel bowl and observed that the float seems to be working 'okay' (that is when I push the float up - simulating a 'full bowl' the fuel flow stops, when I drop the float a little, fuel flows into the bowl.) However, it seems like the my problem is in this area - any suggestions ??? Thanks in advance and Happy New Year !!! Regards, Tom Kelly Milford, CT Link to comment Share on other sites More sharing options...
Cal Posted January 1, 2001 Share Posted January 1, 2001 Al is right, but another problem could be ice forming in the carb. you should be using the sheet metal heat containment baffle that ataches to the 2 screws that hold the air filter in place. THis needs to be used in snow conditions or the intake area of the carb. will build up with ice choking off the engine causing fuel to not be drawn into the cylinder when the engine stops residual heat from the engine will melt the ice and after a few minutes the engine will restart. I probably have 1 of these baffles if you don"t. happy new year Cal Link to comment Share on other sites More sharing options...
Yeoman627 Posted January 1, 2001 Author Share Posted January 1, 2001 Thanks for the help guys ... With respect to the 'freezing' theory ... I don't think I have a 'containment baffle' as you described. Please refer to the picture. You're not refering to the 'Heat Shield' between the muffler and carburetor, right ? The "two screws" that you are refering to are the ones indicated on the picture ? I'm leaning toward that [icing] theory because I over the summer I rebuilt the carb, and it was running fine (warm weather). I started having this problem in the colder weather (the other day) when I was blowing snow (coincidence ??? - maybe). In addition, the behavior that you described is consistent with what I experienced - working after the engine was off. I noticed in the Owner's Manual for the snowblower, in addition to the weights there are other 'winterizing' accessories recommended - a fuel cap (#106798 - which I have), a film sheild (#170252), and a heat deflector (#161296). I do not have either the 'film shield' or the 'heat deflector'. Nor could I get any decent description of what they do, what they look like, or how they mount. Perhaps one of these are what you are refering ? I'm also looking into the possibilty of contanimants by way of either a bad fuel filter or deteriorating fuel lines which would cause the needle/seat to malfunction overflowing the fuel bowl. Finally, I would be interested in one of those baffles. Thanks again, Tom K. http://pages.cthome.net/atkelly/images/broadcarb.jpg Link to comment Share on other sites More sharing options...
Cal Posted January 5, 2001 Share Posted January 5, 2001 Tom you are correct the heat baffle that you are in need of attaches to the two air filter screws that you point out itcomes down over the outside of the carb. to draw in some heat from the exhaust. the transfer that you rrefer to in the parts breakdown is adecal REMOVE THISSHIELD IN SUMMER if you would like me to send you one E-mail me your address to mail it to. This is only reccomended for snowblowing not snow plowing. I would like $5. for postage & pkg. Cal Link to comment Share on other sites More sharing options...
Cal Posted January 5, 2001 Share Posted January 5, 2001 Tom you are correct the heat baffle that you are in need of attaches to the two air filter screws that you point out itcomes down over the outside of the carb. to draw in some heat from the exhaust. the transfer that you rrefer to in the parts breakdown is adecal REMOVE THISSHIELD IN SUMMER if you would like me to send you one E-mail me your address to mail it to. This is only reccomended for snowblowing not snow plowing. I would like $5. for postage & pkg. Cal sorryIdo not have the ability to send a picture as you do good shot of the exact area of disscussion Link to comment Share on other sites More sharing options...
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