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gjh

Fuel Starvation Briggs 12-FIXED!

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gjh
I've owned a Homelite T12 with a Briggs for about 10 years. For the longest time the tractor will stall out when running on a side slope, I thinks it's when it leans to the right. It doesn't have to be that much of a slope and if it starts stalling usually if I make a quick 180 it will keep going. I'm thinking it's the float level height. Strange it hasn't acted up all winter, but then today I was blowing my driveway with no side slope, but a slight incline and it keep cutting out. I already have a fuel shut off because I have the infamous Flo Jet drip. Is the setting to make the float parallel to the carb body? Thanks

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gjh
I'm pretty sure that's the way I set it up. Another note I should have mentioned I almost always have to spray a little starter fluid in to start the machine. If I shut it off I may have to spritz it again; poss the same issue with float level?

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larry8200
Using starting fluid on small engines is STRONGLY discouraged, the ether washes oil off the upper cylinder walls and can cause serious damage. The hard starting suggest to me a vacuum leak or a main jet that is partially obstructed or a choke thats not closing all the way, or a combination of them. With the engine running you can use your starting fluid and spray it around the manifold between the carb and engine, if the engine speeds up you have a leak. If the jet is obstructed richening the mixture may not have any effect, I dont know how to check the choke with the carb on the engine without removing the "welch" plug, which wont want to stay on again. I would also remove the line from the carb and make sure you have a constant stream of fuel, there is a screen in the tank that can get clogged. If your float leaks it wont "float" and will cause your drip, with the float out shake it and make sure nothings in it. Briggs has replaced the brass floats with plastic, alleviating leaking floats. They sell for about $7/piece. I've been replacing all ny old brass floats, one by one.

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superbee
Man, I know your problem well!!!! Did you have fuel poor out the bottom of your carb? I ask first, but it could be very simple, check your hose, replace if it is hard, check your valve on you gas tank, it has a filter, and to check this remove it, replace it anyways, your tractor is 40 years old!!!! I would suspect as others have mentioned, to check your float level. I will tell you i have worked on many of these B series tractors, and restored them. Take my advise, put you float level to a slight angle upwards, try 10 degrees using a protractor , or just a 1/8 inch from the base of the throttle body, OK? Any questions ask me please, hope I helped, Dave

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superbee
Yes you have the same problem I have seen so many times before. Do you have your carb remove yet? You'll have to do it, and get the kit rebuild in case, but you need to know how to do this this rebuild right, I will help

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JimDk
Gary, Is your inline filter the correct one for a gravity flow system? The filters for a pressure system don't flow well with just gravity. I check mine by pulling the hose at the carb and flowing some gas into a can. I look for a good full hose flowing.

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PhanDad
I've found with both my Homelite T-12 and GTHL (both with single cylinder Briggs), when the gas tank is low, and under a fair engine load, going uphill or on a slope with the carb on the uphill side, the engine will stave for fuel. Just not enough head in the tank to get enough fuel flow for the engine demand. It'll run for a while with the fuel in the bowl, but with the outflow greater than the inflow, the engine will start to stumble. I agree with all the comments about making sure nothing is plugged or restricted, and the more items in the line (filter, shut off valve) the greater the required head in the tank to maintain flow for the engine under load. I've also found an occasional total removal of the high speed needle valve assembly to allow a good purge of the gas line system helps prevent fuel starvation, especially on the much older Homelite. I'm thinking maybe there's some degradation of the inside of the old rubber fuel lines between the filer and carb that might, over time, impede fuel flow. Should change those lines someday.

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gjh
All new hoses 4 years ago, but with this lousy E10 gas I think I'll replace them again. I replaced the in line filter and it was really tough to get off, line seemed a little swollen. Filled the tank 3/4 also and no real change. Today while blowing snow I definitely identified that if I run on almost any kind of an up hill she stall under load. I mean really slight slope. Gonna pull the carb clean it out and re-adjust the float so that it is a tad lower to the carb body. I don't worry about leaks when it is not running as I use a shut off anyway. Will keep you posted. BTW the $900 for my 30k BTU Modine hydro unit in my garage was the best money I spent this year! I can finally work in the garage with just a sweatshirt & the over sized unit lets me bring the temp up from 40 to 55-60 in less than an hour.

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larry8200
quote:
Originally posted by gjh
New hoses all the way from the tank, no screen in the plastic Homelite tank, but i have an in line I really should change. Installed an inline shut off cause she does drip if left to sit.
I would double check that screen, all my plastic tanks seem to have screens and one caused problems. RayS on plastic tank screens: "Any of them I have seen they had them. I break them off and put a inline fuel filter on. My 916H acted as if it was starving for gas. It ended up being that screen was restricted." This is the tank out of my 7112H


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gjh
Oh, I thought there was a molded nipple on the end, I haven't looked at it in a while. Does the plug get glued in? Remember this is a Homelite, not a Simplicity, they did some different things. I'll check it our tonight.

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larry8200
quote:
Originally posted by gjh
Oh, I thought there was a molded nipple on the end, I haven't looked at it in a while. Does the plug get glued in? Remember this is a Homelite, not a Simplicity, they did some different things. I'll check it our tonight.
I thought there was a molded nipple too, untill I pulled one out accidentally. As far as I know now, all Simplicity's and AC's had a screen in the tank. And either Simplicity or AC Built your T12. If your tank is drained you should be able to sse with a flashlight.

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PhanDad
A/C Homelites don't have the same plastic gas tanks as do the Simplicities. Trust me, I know. The A/C Homelite gas tanks have a molded in 90 deg nipple pointing toward the left of the tractor. There is no separate part that plugs into the bottom of the tank. I know because the nipple split open on the "weld" seam on my original gas tank in my T-12. Drained the entire contents of the tank on the floor of my "shed". I don't have a pic of the tank, but you can see the 90 deg nipple in the parts schematic:


There is a possibility that junk could collect in the small sump that the nipple is molded into and restrict flow. If you disconnect the line before the filter, see how fast the tank will drain, that should tell you if the sump is restricting flow.

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MrSteele
I repaired a Crapsman used to pull a train at a kid's fair with your same problem. The owner had bought a new filter on the way to the carnival, so he knew the filter was not the problem. Problem was, he had bought a new filter for a pressure, not a gravity system. The grade the tractor would not pull can hardly be called a grade. The engine ran fine the rest of the way around. In a pinch, I stuck a screwdriver through his filter to increase flow, and it ran fine. I put the proper filter on it, and I suppose it is still running fine. I have a Dixon with the line going into the bottom of the tank like in the pics above. Briggs and Stratton makes a fuel shutoff valve that can be placed into the bottom of the tank, though I do not know the part number. It is rather hard to shove into the tank, but it seals simply because the rubber grommet fits so tight. You might want to talk to your parts man (person) and purchase one. An inline filter close to the carb, and you are in business. I would try the line and filter before raising the float. I run all my floats a little low, on small engines and a couple of old cars, keep flooding at bay.

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HubbardRA
It sounds like the mounting bolts may be a little loose and the whole carb/manifold assembly may be swinging to the side and opening up a vacuum leak. It doesn't take much to cause a leak. Any movement is too much. Most times a little metal is turned up around the holes when the parts are bolted down. If you then use one of the very thin gaskets, it will not compress enough to seal properly. I have run into a couple of instances where I either had to find a thicker gasket or install two gaskets to get enough thickness for the gasket to compress when the bolts are tightened. I have also chamfered the holes in the manifold a couple times to get rid of metal that had been pushed up from overtightening of the bolts. My 12 Hp tractor will run at a 30 degree angle in any direction with no change in the way the engine runs. It also has the "drip" problem and has a shutoff valve to prevent fuel from leaking out.

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gjh
So, replaced the fuel filter with a lawn & garden variety, removed the fuel line at the carb. This tests flow through the entire system including filter and shut off. Also checks to see that the lines are not swollen from that wonderful E10 crap. Fuel flowed pretty steady into the can, so I assumed that was not the issue. Pulled the carb off and cleaned it out. No real signs of gunk. The float was set to just about level, so I adjusted it just a hair so that it would have to fill up just a bit more before it shut off. I'm talking a 1/16th at the most. I did not have a carb kit and the float bowl gasket was stuck to the body just a bit and the smooth coating stuck in a few places. Cleaned it up best I could and used a little high tack on the outside by the bowl to prevent leaks. Checked that intake manifold was tight and it was. Sprayed the carb-manifold gasket with some high tack and got that nice and firm. So, still need a spritz of gas to start and it was running rough till I got it adjusted. Ran in driveway for 15 mins; seemed OK, but still not like it should. Seems the governor runs up and down at times. Started plowing and it ran decent at high throttle and would idle decent, but not great. After 1/2 hr started to stall and backfire, then start running again. I did notice one thing, it would not re-start without priming with either, I know bad. Once I got it started and drove right off it seemed to keep running. So I parked it and every time it started to stall I just shook the tractor side to side and it would keep running. Sure sounds like a float issue to me! Your thoughts?

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gjh
Problem Solved! So, pulled the carb off, but before I tore into it I thought I'd change the fuel hose from the filter down and by pass the filter for the heck of it. I did notice when I turned the carb over there wasn't that much fuel in the bowl. Without pulling it apart I just threw it back on on tried the tractor. It ran great! Idled, ran fast and I plowed for 2 hours without an issue. So; now to my problem. What was wrong? I'm tending to think it may have been the filter. When the machine started acting up a week or so ago I thought the filter may have been dirty because it's had been quite a while since I changed it. I'm thinking it may have been the new filter form Home Depot. Was in the mower section, but who knows with them. Haven't had a chance to put the filter back on, but I'm betting that was it. Thanks for all your input!

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larry8200
I've heard some filters restrict flow too much on gravity feed systems even when new. Never had that problem myself. Who Knows? I've used Wix G-2 inline filters on everthing for... long time, no problems. I like that I can see what shape it's in. At Walmart for less than $3.00.


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JeffNemes
Gas filters do have different micron ratings as already stated - we have run into problems by installing to fine a filter trying to keep dirt out but when the fuel heats up they actually can cause not enough fuel flow.

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