RPM up and down B7500 ?

[thetooth]

Drove over to my fathers today to mow down his garden . He is about a mile away from my house . Tractor drove over fine , but after about 10 minutes of mowing down his garden my RPM' s started to drop a little ( RPM was at 2600 in low gear ) I didn't think much of it because I was mowing down some heavy weeds and old tomato plants . I just figured the mower was bogging down a little .

On the way back home In high gear at the same RPM ( 2600 ) the tractor did the same thing and even dropped down to 1500 RPM . It did this 3 times and around the half way mark It did not do it again . Temp gauge was fine and so was the air filter . Tractor has had a full service at 445 and there are 472 hours on it now .

Hints or tips ? I was just thinking maybe a little bad diesel .

thanks

 

[BigD23]

Fuel filter?

 

[TripleR]

Is your engine bogging down or is your throttle slipping down and you can bump it back up?

 

[easygo]

It might be worth it to check the linkage for the throttle. Once I had a rather small branch caught in the HST pedal linkage and it was flexible enough that I could change directions but strong enough to push the pedal forward and make the tractor go forward.

 

[thetooth]

Fuel filter?

Fuel filter looks okay it's only 27 hours old .

 

[thetooth]

Is your engine bogging down or is your throttle slipping down and you can bump it back up?

The engine was bogging down

 

[TripleR]

I always replace the fuel filter as a starting point then check fuel lines that can become pinched or clogged. I have had this symptom in older tractors and replaced the fuel pump. With a low hour, well maintained engine this should not be a problem.

Hopefully someone with more mechanical knowledge, not a high bar, can help.

 

[leonz]

The fuel tank is the first stop, the screen is being plugged
and the movement of the tractor and the fuel being sloshed
back and forth is moving any of the debris around with it.



leonz

 

[thetooth]

Well I mowed again for about a 1/2 hour around the yard and it did not do it again , maybe it was just a fluke or a little moisture in the fuel line .

 

[thetooth]

The fuel tank is the first stop, the screen is being plugged
and the movement of the tractor and the fuel being sloshed
back and forth is moving any of the debris around with it.



leonz

Is there a screen in the bottom of the fuel tank ? I am going to follow TripleR 's advice and replace the fuel filter .

 

[TripleR]

As leonz pointed out, you can get some intermittent crap sloshing around in your tank. I used some HEET (for diesels) and some fuel additive to clear up an intermittent problem with my old BX2200.

leonz and others have helped me out on these issues often.

 

[thetooth]

As leonz pointed out, you can get some intermittent crap sloshing around in your tank. I used some HEET (for diesels) and some fuel additive to clear up an intermittent problem with my old BX2200.

leonz and others have helped me out on these issues often.

Thanks . I put some diesel fuel stabilizer ( CRC Brand ) and some Lucas fuel system cleaner when ever I fill the can up .

That theory make sense though about something sloshing around in there . It could be a stink bug we ( North East ) are infested with them right now and they can squeeze into some tight spots

Appreciate everyones help

 

[thetooth]

Okay . I changed the fuel filter this weekend and my problem persist . Even with the tractor stopped on level ground the rpm's will drop below 1000 from where I have it set at around 2000 . It will sputter for a couple of seconds then start to rise back up .

My fuel is about a month old with a CRC water additive and some Lucas fuel treatment .

Should I drain the tank ? Is it possible the Air filter ( about 30 hours old and I just blew it out when I changed the fuel filter ) .

Thanks

 

[thetooth]

So this is what's happing . I pulled the full line from the tank to the filter and got good flow . The tractor is using more fuel that what is being fed to the filter at high RPM 2000 or above I can watch the fuel level go to 1/4 inch above the bottom of the filter and it will start to sputter once the level is below the bottom of the filter .

Is there a screen in the bottom of the tank ? could it be the fuel pump ?

thanks

 

[leonz]

The screen is in the bottom of the tank.

The chances are the fuel line is either

plugged and or collapsing.


The issue is the fuel inlet in the tank; if the

tank has a bottom draw the tank has to come

off to clean it and replace the fuel line to the

injection pump.


The inlet screen may be gone and you are

sucking it all in the fuel ine.


Does the tank still have the fuel filler sreen

basket in the filler neck?


I must suggest to you to replace the air filter

as you may have put a pin hole in it when you

blew it out.


You can eliminate the screen and uses a larger

fuel delivery hose by installing a Racor model

1100 fuel filter(5 micron filtration) unit to

eliminate the issue with junk in the fuel

tank and water as it will spin the dirt and

water out of the fuel for you with the suction

of the fuel pump.

 

[thetooth]

Thanks for the info leonz . I pulled the fuel line off from the bottom of the tank to the full filter and the tractor seems to be running better ( maybe it had some air between the fuel line and the filter housing ? ) . If the problem persist I will follow your advice .

Thanks for your help