UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?

FatJack

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
Hi Gang, Hoping somebody might have run across this problem: My Craftsman tractor has a Briggs & Stratton "Platinum" 540 cc, 21 hp engine. It runs great with a full tank, but stalls out as the fuel level approaches 1/2. I thought it was a fuel line or filter issue, so replaced filters and replaced lines and didn't help. This problem is two seasons old now, just filling the tank is an ok work around, but thought I might try to fix it this summer.

I'm thinking it might be a dirty carb issue, but not sure why the 1/2 tank vs full tank would matter, unless a full tank supplies more pressure to push fuel through??? Not sure if that is even possible.

Before I spend the time take apart the mower to get to the carburetor, I was hoping someone could confirm that it is likely a carburetor problem. If it is, should I replace carb or just clean it? (10 years old tractor).

Adding my "solved" post here for convenience:

UPDATE: Hi All, thank you for all of the input. Yesterday I swapped out the paper filter for one of those red plastic filters (yes, the same one that Steve's video says is worthless) and now the engine runs great right down to empty. I also made a slight change in the fuel line path by bypassing the little plastic harness that hangs off the bottom of the fuel tank. That harness keeps the fuel line from flopping around but also makes the first few inches totally flat instead of a nice downhill feed down to the carb. I believe the original filter was the red plastic type and I changed it out for the "good" kind a few seasons ago because that is what Sear Parts Direct gave me as a compatible filter. I changed it out a 2nd time when this problem came up last year, so a dirty filter was not the issue. I suspect that the paper filter is just too fine unless you have a fuel pump to force the fuel through.
 
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Rivets

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
How about posting the units model and serial numbers. Briggs has lots of engines out there and I really really hate guessing which one you have. Look on the valve covers
 

slomo

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
This time of year, very well could be a carb issue. People are dragging out mowers for the season.

slomo
 

StarTech

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
It also would to have the mower model number too.

We are not physic.
 

slomo

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
Does your engine have a fuel pump? Might be a partial clog on the carb needle.

I would drain and FLUSH the fuel tank. Install new hoses with a paper filter and a fuel shut-off valve. Clean and or rebuild the carb.

slomo
 

FatJack

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
The Tractor Model # is 917.289223. The serial # on the engine cover is 090 928 ZD 64 948

Thnx!
 

FatJack

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
Does your engine have a fuel pump? Might be a partial clog on the carb needle.

I would drain and FLUSH the fuel tank. Install new hoses with a paper filter and a fuel shut-off valve. Clean and or rebuild the carb.

slomo
I've already cleaned the fuel tank, lines and changed filters so I guess I'll be pulling the carb tomorrow. Thnx!
 

FatJack

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
Sorry guys, clearly I need help! The right model number from the valve cover is 331877 1371 B1 090925Z

Any additional advice is appreciated. Otherwise, I'll start taking it apart to get to the carb. Thnx!
 

semimechanicman

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
Hi Gang, Hoping somebody might have run across this problem: My Craftsman tractor has a Briggs & Stratton "Platinum" 540 cc, 21 hp engine. It runs great with a full tank, but stalls out as the fuel level approaches 1/2. I thought it was a fuel line or filter issue, so replaced filters and replaced lines and didn't help. This problem is two seasons old now, just filling the tank is an ok work around, but thought I might try to fix it this summer.

I'm thinking it might be a dirty carb issue, but not sure why the 1/2 tank vs full tank would matter, unless a full tank supplies more pressure to push fuel through??? Not sure if that is even possible.

Before I spend the time take apart the mower to get to the carburetor, I was hoping someone could confirm that it is likely a carburetor problem. If it is, should I replace carb or just clean it? (10 years old tractor).

Thnx!
Try to run it again until it shuts off and then take off the fuel cap or unscrew it a little. Maybe it is the cap that is blocking from air from flowing inside.
 

FatJack

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  • / UPDATE: SOLVED! Only runs if tank 1/2 full +?? Carb problem?
Try to run it again until it shuts off and then take off the fuel cap or unscrew it a little. Maybe it is the cap that is blocking from air from flowing inside.
I think I tried that last summer, but I'll give it another shot. If it works it's a lot easier than taking the carb apart. Thnx!
 
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