7520 missing and smoking

[wildstreak]

I bought a used 7520 with 303 hours on it. The tractor is in very good condition. Sometimes(not on a regular basis) it will just start blowing white and blue smoke and missing.
I can stop and turn the engine off and restart it and it stops. Sometimes it may not do it at all and sometimes it may do it 2 or 3 times in an hour.

 

[RedRiver]

does it do it immediately upon cranking the tractor up or does it take it a while to start missing?

if it does it immediately or within the first 20 min. or so it's likely a bad KSB timer. contact your local dealer and they more than likely will have one in stock. if it's been running a while and then starts doing it, it may need the timing adjusted.

it could be bad fuel also but I'm betting its the KSB timer.

 

[wildstreak]

Thanks for the information. It does not do it upon start up. The first time it did it the tractor had been running about an hour.

I was wondering if it was possible for the key switch to have something to do with it?

I'm new to the Mahindra family and don't know much about the brand. I was in the logging business and I am machanically inclined. I know how to work on skidders and saw heads(such stuff as that). Mostly the JD brand.

How does the KSB unit work?

 

[SPYDERLK]

Thanks for the information. It does not do it upon start up. The first time it did it the tractor had been running about an hour.

I was wondering if it was possible for the key switch to have something to do with it?

I'm new to the Mahindra family and don't know much about the brand. I was in the logging business and I am machanically inclined. I know how to work on skidders and saw heads(such stuff as that). Mostly the JD brand.

How does the KSB unit work?

KSB advances the injection timing for the 1st 20 min after a cold start. I was told it did this after any start, but it doesnt seem to when the engine is warm. If you are near the tractor idling when it kicks off you will hear the engine go smooth and quieter.

I think you are experiencing cold stacking after the timer times out. After this it is more important to idle faster and DO WORK to keep the cylinders warm enuf to burn all the fuel. Same thing happens to me when the weather is cool.
larry

 

[wildstreak]

Thanks. So, I should just replace the KSB unit. From what I see on here this is somewhat common. Again, thanks.

 

[jwcinpk]

Sounds like injector timing more than the KSB.

I had a similar problem with my 7010 and it was the injector timing.

 

[SPYDERLK]

Sounds like injector timing more than the KSB.

I had a similar problem with my 7010 and it was the injector timing.

Yes, thats what I think it is with mine [7520] - retarded timing. Mine never cold stacks and seems to run a little better before the KSB kicks out. After that mine will cold stack pretty readily even in warm weather if I dont keep it working. I think wildsteaks KSB is working because he doesnt have problems til it kicks off after about 20 min running - just like mine. Anybody know which way to turn the pump to advance the injection?
larry