7520 not running right, poor power, white smoke

[jrchafin]

Hey guys,
My 7520 which is 1.5 years old and has 112 hours on it started acting up today. Was bush hogging and noticed a drop in power, then it ran rough, spewed some smoke (?black I think) for a second, then returned to normal. Whole thing lasted about 15 seconds. I thought maybe something in the fuel line and went on. Worked for another 1/2 hour where it ran fine, then it did it again, but didn't go away this time. Running like it's intermittently getting fuel, rpms will go up, down, up, down, down, stall. Restart, up, down, up, down, etc. Now it is definitely spewing white smoke.

All maintenance is up to date. Just changed the engine oil last week.

I had it in for service around 50 hours because it wouldn't start cold and the preheater wasn't working. They told me that it had a bad ground and they "cleaned all the connections". It has worked since, but I've noticed that the past couple months it needs to crank more than I would expect to start up. It used to start in <1 second of cranking, now it takes 2-3 seconds. I've been wondering if I have the preheater problem again, but it's summer and it starts anyway. Don't know if this has anything to do with it.

Ideas? Thanks!

Jon

 

[BobG_in_VA]

Couple of things....have you changed/drained your fuel filters? Also, check the fuel tank cap...sometimes they can get a vacumn in them and cause fuel not to flow correctly. BobG in VA

 

[jrchafin]

I opened the drains at the bottom of the fuel filters and checked for water/sludge, but found clean diesel, so I didn't drain further. Should I? I also checked the drain at the bottom of the tank with the same result. I looked at the cap but don't see any air vent on it. Isn't the cap supposed to have a vent to prevent pressure?

Anyway, I haven't had a chance to test it again since, will try again tomorrow. Thanks for the info.

Hey Bob, where do you get your tractor serviced? Are you happy with them? I've been dealing with the guys in Stuarts draft with little satisfaction, and would like to change.

Jon

 

[BobG_in_VA]

I opened the drains at the bottom of the fuel filters and checked for water/sludge, but found clean diesel, so I didn't drain further. Should I? I also checked the drain at the bottom of the tank with the same result. I looked at the cap but don't see any air vent on it. Isn't the cap supposed to have a vent to prevent pressure?

Anyway, I haven't had a chance to test it again since, will try again tomorrow. Thanks for the info.

Hey Bob, where do you get your tractor serviced? Are you happy with them? I've been dealing with the guys in Stuarts draft with little satisfaction, and would like to change.

Jon

I pretty much do my own thing...the nearest dealer to me now is either in West VA, or south of Richmond....besides Beverage (I thought they lost their dealership, as I looked on the Mahindra website and couldn't find them anymore....)As far as the fuel cap, loosen it and see if a vacumn hiss comes back at you if it does it again. Fuel Filters: if you are getting good clean flow, those are probably OK...let us know if you still have problems next time you run it. BobG in VA

 

[jrchafin]

Still having problems.

On starting today, it had to crank a VERY long time to get going, like it wasn't getting any fuel. Probably a full 10 secs of cranking. Then it has no power. It will idle up, but as soon as you put even a little load on it, it spews white smoke and stalls.

I'm going to drain the fuel and put fresh fuel in, take the filters out and have a look, bleed all the fuel lines and try again.

Is there anything electrical? Is there a fuel pump relay?

 

[Blu 82]

I had starting problems with mine and $900 later, the Massey Fergusen dealer found that it was a relay--not sure which one but it is about a $30 dollar part (check Bills Tractor). May have been starting relay. Why did I have MF dealer do the work--because my Mahindra dealer lost his business and the nearest dealer was about 90 miles away and it would have cost about $800-900 just to transport tractor to them. One can argue whether I should have paid MF dealer to "learn" my tractor but what could I do?? I didn't have expertise to fix sooo... It is working fine now with about 450 hard hrs clearing land, building barn foundation, planting corn last yr (first time for me, I am a beginner in farming), cutting about 8 acres of grass... It is a workhorse and has taken my newbie abuse.

I wish I had a mentor farmer to help me learn.

Good luck.

 

[jrchafin]

I think I may have found the problem, and it ain't good. I discussed this with a tech at the dealer, and he told me that they have problems with the injector pump on this model (7520). Well, like I said earlier, I drained the fuel tank, checked the filters, and put fresh fuel in the tank. I bled to the banjo bolt (just after the secondary filter) with no problems. I then bled to the bolt where it enter the injector pump, no problem. I think cracked the high pressure lines on the other side of the pump loose, and I am unable to pump anything through. I pump and pump, no fuel. I bumped the engine to change it's position which didn't help.

End conclusion: I think I have a bad injector pump. Good news is I'm under warranty. Bad news is the guy I bought the tractor from says he doesn't do warranty work anymore for Mahindra. More bad news is wherever I go, I'm going to have to haul it.

 

[LAWALLSTRACTOR]

Could you possibly have a sticking fuel shut off valve. It is located where the fuel goes into the injection pump and has a single wire going into it. I had one that acted this way but it also didn't want to shut off. It was starving the engine for fuel, but also wouldn't close to shut the tractor down when you turned the key off. Unhook the wire and turn the valve out and make sure the plunger on it is moving freely. Be careful to not lose the plunger or spring.

 

[SPYDERLK]

Could you possibly have a sticking fuel shut off valve. It is located where the fuel goes into the injection pump and has a single wire going into it. I had one that acted this way but it also didn't want to shut off. It was starving the engine for fuel, but also wouldn't close to shut the tractor down when you turned the key off. Unhook the wire and turn the valve out and make sure the plunger on it is moving freely. Be careful to not lose the plunger or spring.

jrlogan-- along these lines - try a lubricant fuel additive. Also, I sent you a P/M. Pls keep us posted.
larry

 

[jrchafin]

Thanks LAWALLSTRACTOR. I will try the fuel shutoff valve, though the tractor does shut down immediately when the key is turned off. I'll let you know how it goes.

Thanks for the advice SPYDERLK, will definitely give it a try.

Am I correct that the hand pump for bleeding the fuel lines should push the fuel through the injector pump on all 4 ports? I've never bled the fuel system on this tractor before.