Engine ID & intermittent issue

[youngstown.bulldog80]

Hi everybody. I have been looking at a 76 R686 that's for sale and there is a discrepancy in the type of engine it has. The seller told me it isn't the original engine, it's a Mack rebuild that was installed new about 20 years ago. On the tag behind the fuel pump it only says "T676" (not ENDT), and on the ridge on the housing in front of the fuel inj pump (where it would normally say the engine type), it looks like there are some numbers stamped on the ridge but I don't think they were stamped deep enough as they've nearly disappeared and are illegible. The 3 oil filters make it look like an EM6, but I'm thrown off by the "T676" on the ID tag. I'm attaching two pics to this posting...

Also, it sat (inside) for over 5 years without being started/driven. The engine itself runs good but the owner tells me there's an intermittent problem. He says every so often, it will start up right away but will rev up significantly. He says it doesn't rev high enough to seem like it's running away, but if the engine stop is pulled out it doesn't shut down the engine...he dumps it in gear to get it to stall. He said that he took the little cover plate off the governor and soaked the insides down with WD40 and worked the control levers back and forth until the freed up (seemingly). Could it just be the governor was sticking from sitting for so long, or does it sound like something more serious - like maybe the plungers in the fuel inj pump? Just wanting to get some input on that. He told me that he started it/shut it down and restarted it about 20 times to see if the problem would come back, but it never did reoccur.

[terry]

ENDT 676 and T676 are the same engine three filters is a ESI engine, should have a extra deep oil pan if everything is correct. Sounds like he might have fixed the governor problem.    terry

Edited July 1, 2018 by terry

[mrgumby]

I’m guessing a turbine tip 300 

[terry]

1 hour ago, mrgumby said:

I’m guessing a turbine tip 300 

A T676 is a 285 horse.    terry

[youngstown.bulldog80]

11 hours ago, terry said:

ENDT 676 and T676 are the same engine three filters is a ESI engine, should have a extra deep oil pan if everything is correct. Sounds like he might have fixed the governor problem.    terry

Thanks for the info. ESI = extended service interval, correct? The oil pan does appear larger than normal so that makes sense. Is the governor problem common when they’ve been sitting a while? 

[terry]

Can't give you a solid answer on the governor, but sounds like it MIGHT be fixed.   terry

[theakerstwo]

Any time a mack has set for some years the rack in the pump can become frozen and can be a problem.I always check to see if I can move the rack before starting.

[fjh]

Run some standyne fuel conditioner thru with the fuel!

[youngstown.bulldog80]

6 hours ago, theakerstwo said:

Any time a mack has set for some years the rack in the pump can become frozen and can be a problem.I always check to see if I can move the rack before starting.

That's a good habit to get into, especially when looking at trucks that have been sitting a while. I will definitely keep that in mind from now on before starting anything that's been sitting a while.