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MTD Riding Mower spitting gas from air cleaner


mitsured's Avatar
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08-29-09, 09:30 AM   #1  
MTD Riding Mower spitting gas from air cleaner

I have a MTD Riding mower model # 136M670G088 briggs and stratton 14.5 HP Motor Model #: 287707 0224-01 Code 9603202D.

A few weeks ago in the middle of mowing it starting to chug and then quit. When I removed the air cleaner cover there was a lot of gas around the filter.
I left the air cleaner off for a week and the next weekend I tried starting the mower with air cleaner cover removed. It started and I allowed it to run. Once the motor warmed up it started spitting gas, not from the carburetor but from the hose that connects to the bottom of the air cleaner housing and to the engine. It of course died.
I pulled the carburetor off and make sure everything was clean and the throttle and choke were connected properly when I reinstalled the carburetor. I also pulled off the hose and the "baffle box" not sure what the hose or box is called, It is connected to the bottom of the air cleaner housing and to a metal box with a baffle that moves back and forth inside, this box is connected below the carburetor on the engine.
Some gas did come out of the little ports behind this "baffle box." I also replaced the needle in the carburetor because the plastic piece at the end was coming off.
I though it might not be sealing properly which was causing the engine to flood. I put everything back together started the engine and once again as soon as it warmed up it started spitting gas. I adjusted the idle all the way down. Let the engine sit for a couple hours and then restarted the engine. After 1 turn of the idle screw the engine started and idle really low. Which was what I was trying to achive. The engine then warmed up and started spitting gas again!.
The plug has been replaced. I have not checked the compression but the engine feels like it has good compression.
The carb does not leak. The mower does not smoke.
I am at a lose and not sure what I should try next.
It has been suggested to me to change the float because it might have a hole and filling with gas. I examined the floor and it looks ok but Iím going to buy one today just to see if it works.
Any suggestions anyone can provide me would be greatly appreciated. I hate mowing the yard with my old push mower.

 
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08-29-09, 11:12 AM   #2  
This really doesn't sound like an adjustment issue.

It's more like the float/float valve isn't sealing the flow of fuel and the gas is overflowing back through the throat of the carburetor into the air filter and down into the crankcase vent tube.

Your problem is likely in the float valve, or the seat the valve mates to or the float itself. With a good float and valve you may need to dress up the seat with a cue tip and some Comet or other abrasive cleaner.

 
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08-29-09, 02:06 PM   #3  
My question is; Have you checked the oil level and smelled it for fuel contamination since it flooded and stalled ?

After performing what marbobj suggest don't be surprised if you still have a little spit-back while running, Most engines do but you just don't see it with the air filter in place.

 
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08-29-09, 02:11 PM   #4  
Posted By: marbobj This really doesn't sound like an adjustment issue.

It's more like the float/float valve isn't sealing the flow of fuel and the gas is overflowing back through the throat of the carburetor into the air filter and down into the crankcase vent tube.

Your problem is likely in the float valve, or the seat the valve mates to or the float itself. With a good float and valve you may need to dress up the seat with a cue tip and some Comet or other abrasive cleaner.
Thanks for the info. I found a place I can pick up a new float. I will be picking up and replacing the float tomorrow morning. I have already replaced the valve-float needle and the valves look to be in good clean condition. I hope the float is the issue.

 
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08-29-09, 04:45 PM   #5  
Posted By: 31YTech My question is; Have you checked the oil level and smelled it for fuel contamination since it flooded and stalled ?

After performing what marbobj suggest don't be surprised if you still have a little spit-back while running, Most engines do but you just don't see it with the air filter in place.
I just checked the oil and yes it does smell like gas.
What does this mean?
Do I just need to change the oil or is this a bigger issue?

 
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08-29-09, 05:35 PM   #6  
It means;

When it flooded out and stalled on you then you parked it for that week the carb let fuel flood into the cylinder down into the crankcase.

This thinned the oil out and raised the level, Thus after working on the carb most likely fixed the flooding problem. But, With the thinned out oil and over filled crankcase it continued to blow oil/fuel mix up through the breather and into the air filter base/carb.

Change the oil with straight 40w then test run the engine, It may smell funny and smoke a little as it warms up but will dissipate after reaching full running temp.



Good Luck

 
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08-29-09, 06:05 PM   #7  
Thanks for the information. This could be very good news!
I will change the oil in the morning.

I normally use 30W should I use 40W instead?

and should I use 40W for just this oil change and then go back to 30W next season or should I use 40W for all future oil changes?

 
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08-30-09, 03:21 PM   #8  
We were told by Briggs reps at a update seminar years ago that with the heat we have here in Florida it's better to use 40w instead of 30w, For that reason is why I use 40w in nearly everything but Kohler Commands which use 10w30.

 
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08-30-09, 07:10 PM   #9  
Posted By: 31YTech It means;

When it flooded out and stalled on you then you parked it for that week the carb let fuel flood into the cylinder down into the crankcase.

This thinned the oil out and raised the level, Thus after working on the carb most likely fixed the flooding problem. But, With the thinned out oil and over filled crankcase it continued to blow oil/fuel mix up through the breather and into the air filter base/carb.

Change the oil with straight 40w then test run the engine, It may smell funny and smoke a little as it warms up but will dissipate after reaching full running temp.

Good Luck
I changed the oil today, used 40w, making sure to drain out every bit of oil/gas that I could.

You were right it did smoke for a few mins after it warmed up but there was not any gas spitting out of the air intake!!!

Mowed the backyard without an issue!

I did pull my landscape trailer from the backyard to the front so I could mow under it and while I was pulling it up a small hill the mower started to stall.

 
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08-31-09, 03:59 AM   #10  
How big is this landscape trailer ?

 
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08-31-09, 04:12 PM   #11  
Posted By: 31YTech How big is this landscape trailer ?
Its a 5' X 8' trailer single axle.

 
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09-04-09, 11:22 PM   #12  
The mower over the past few month has started going slowing in forward than it does in reverse. Could this be an issue with a worn drive belt?

 
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09-05-09, 04:37 AM   #13  
gas in oil

when you change the oin did it look siverish

 
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