B7500 intermittent stalling

[moonz]

hi all,

My B7500 that I seldom use has started stalling when I try to use it to cut grass.

It will start up fine when it is cold, and works perfectly for a while, but then it starts to bog down when I come to an incline, and eventually it will even start to loose power on level ground.

It does this intermittently...working fine for a while...then all of a sudden it will loose power and bog down to where it will barely idle, and may even stall.

Then, if I try to re-start it, it may or may not start right back up.

After it sets and cools down it will start up with no problem.

Then the rpms start to fall off kicking the pto out does no good, so I don't think it's related to the mowerdeck.

The deck blades turn by hand very easily, and I keep the deck lubed.

I'm thinking it is bad fuel, since the tractor sets for long periods without any use.

I'll try replacing the fuel filter and see if it clears things up.

I was just wondering about draining the fuel tank...since I have no service manual I was wondering if this is a no-brainer?

Is there a screen on the bottom of the tank as the fuel line leaves the tank that might need to be cleaned?

Will just taking the fuel line loose from the fuel filter on the tank-side allow the tank to completely drain out through the line?

And...after I have the tank drained and re-fueled, and have replaced the fuel filter, what is the procedure for bleeding the air out of the fuel line?

Any replys would be greatly appreciated.

Thankz,

-moonz-

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[NIXON]

Moonz .
I'd look at the fuel and fuel filter . As you said it was seldom used . Could be a combinationm of old fuel and Junk in the fuel lines . John

 

[don716]

I think your fuel and filter is the problem.As your tractor runs the fuel filter pulls fuel through the filter and it starts to clog up and it can only take so much.It then stalls.After it sets over time the dirt falls back to the bottom and it starts all over again.I would drain and replace your fuel and filter.
Donny

 

[Kelvin]

I just went though the exact same thing with my B2150 this past week. Since it had been one year since I had changed the fuel filter, I decided to change it, and sure enough it was clogged up pretty bad.

With a new fuel filter it ran fine for about 5 minutes and the problem started again. I took the fuel line off that goes into the fuel filter assembly and the fuel just barely dripped out. I blew compressed air into the fuel line (blowing fuel back into the tank) and then the fuel started pouring out like you would expect it to.

I put it all back together again and it ran for another 5 minutes before it started the problem started again. So apparently, there was junk in the fuel tank that was blocking the fuel from coming out of the tank. I pulled off and cleaned the tank and blew the fuel line out from both ends. I never did see any junk come out of the tank or the fuel lines, but after putting it back together this time I was able to mow for nearly 5 hours without any more problems.

Hope this helps. In lieu of pulling the fuel line off the fuel filter assembly (like I did), you might try to see what fuel flow comes out with the filter off with the fuel ON/OFF valve in the ON position.

I went out and bought a new diesel fuel can with a screened inlet to help pre-filter the fuel I buy.

Hope this helps,
Kelvin

 

[Egon]

Not sure about the correct procedure for bleeding the B7500 fuel system but on my B7100 it's a two step operation.

First there is bleed on the filter outlet. When this is done there is another bleed on injector pump outlet. For this to bleed I close the throttle and crank the engine over till a steady fuel spray comes out of the bleed. Close bleed and start as normal.

I get to do this at least two or three times a year as the tractor does'nt have a fuel gauge and the plastic tank is to opaque to see the fuel level. I keep the correct sized wrenches in the tractor tool box just for this job.

Egon

 

[moonz]

Thankz for the suggestions, all...I've grabbed me a new fuel filter, printed out a diagram of the fuel tank/tube assembly from the free TractorSmart parts PDF for my tractor model, and now I'm off to tackle a fuel tank cleaning and fuel filter change.

These forums are the greatest... /forums/images/graemlins/wink.gif

 

[Woodsman_Pete]

From my experience in the heavy construction industry, High Sulfur (off-road) diesel will grow an algae like substance, most fuel tanks on equipment sit right on top of or near the hydraulic tank/reservoir which naturally becomes hot after running for a while. The heat will warm the fuel in the tank creating a welcoming in environment for the algae to form (warm and dark). We treat our fuel with a conditioner in the 500 gallon tanks that have filters on them and also in the tanks of the machines. I treat the fuel that I run in my BX2200 about everyother tank. I have seen this problem alot it happened to a buddy of mine with a JD50 mini-excavator and sure enough it was algae. All you can do is clean out the tank blow out the lines and replace the filter, bleed the system and treat your fuel.

Hope this helps

 

[moonz]

Sounds like a good idea, Pete...do you happen to know offhand what the name of that fuel treatment product is?

 

[Egon]

When getting a diesel fuel additive make sure it does not have any alchol in it. The alcohol is not good for the pump.

Egon

 

[Woodsman_Pete]

I'll look tonight when I get back home, I actually had the bottle in my hands last night, and I can't recall the manufacture of it.