I have a 73ish 870 diesel/PS that has been in the family since 1980 or so. About 4000 hours, less than 100 on a major overhaul, but that was 15+ years ago. It has been sitting in the barn for 8-10 years at least, only being started once every year or two, to splash some oil around.

Now for the issue, the last time it was started, it idled perfectly at 800-1000 rpms, but as the speed increased it ran rougher and rougher to the point of coughing and sputtering.

It has a good flow of fuel to the pump. It would seem to me that it is a stuck governor in the pump. Where exactly should I be looking. I have a top notch diesel shop 2 miles away, but money is tight and I'd rather not take in the pump if it can be avoided.

Also I have a good low hour 770 pump(whole tractor for that matter, but it needs more $ worth of tires, rebuild, and radiator than the tractor is worth), will the pumps interchange (aside from turning it up)? Should I keep the 870 timing gear, or can I use the one on the 770 pump.

I would like to get it running, as I can see myself farming a little this coming year, and need a little more tractor than my 1210 for tillage.

Thanks, rich

The last thing I would suspect on that unit would be a problem with the injection pump. They are the most trouble free pump ever built. I would get it running, if the fuel smells bad or shows any evidence of algae, a black thick slimy substance, drain it and refill the tank with fresh fuel, add an algeacide and a good fuel conditioner that will cut varnish that may have built up while sitting to the fuel in recommended proportions, change the fuel filters and start it up. I am not sure the 770 pump has the same size plungers or not, not that it would'nt work but that would be the last resort, It probably needs a good fuel system cleanup and some running time. mEl

If you have 8-10yr. old fuel in the tank I would be draining it or adding new fuel to it, plus fuel addative. Then I would get the tractor out and run it for a while. Fuel that old could be loaded with bacteria, and parafin wax could be guming the pump and injectors up. Let the old girl have some excersize.It could well fix it's self.

Might want to run it for couple hrs at speed it doesent miss. Just running it couple minutes a year might have caused corosion or rust on valves an they might be sticking. Wouldnt hurt to remove valve covers an make suure all of valves are lubricated. Wouldnt hurt to squirt marvel mistry oil on stems.

agreed with other posters ,,. probably got alot of condensation fouling up the works too ,, drain sump in tank ,, i would bet silted shut from settn ,, change fuel filters , check the air filter for everything ,,.. that tractor SIMPLY needs to have some exercise,, don't mess with internals YET ,. and get back to us,, we love hearing these ol cases run ,..

agreed with other posters ,,. probably got alot of condensation fouling up the works too ,, drain sump in tank ,, i would bet silted shut from settn ,, change fuel filters , check the air filter for everything ,,.. that tractor SIMPLY needs to have some exercise,, don't mess with internals YET ,. and get back to us,, we love hearing these ol cases run ,..

also look at air filter -- make sure no mouse nest

Air filter clean, fresh filters and fuel.

How old is the fuel in the tractor? That would be my first place to look, then fuel filters. I have never heard of a pump going bad sitting there.

Just my opinion