'87 GMC - Slow or no cranking

[Jason Spears]

I'm stumped. My '87 is having trouble starting. It has been happening for a while. The starter is having a very hard time turning the engine over. It cranks very slowly. If the engine is hot, it sometimes cannot turn the engine over at all.

Last week end I took the starter off and had it tested. It tested ok. (I'm not terribly confident in this because it took three people at Partsource to figure out how to test the unit.) I ended up replaceing the battery because it tested bad.

The truck started ok (but not normal) for the first part of the week, but by the end of this week I was back to where I was before. I started to suspect the alternator so I took it to get tested this morning and it tested ok.

The engine is pretty worn and I plan on changing it out in a few months. I though maybe I spun a bearing or something but I turned the engine over by hand this morning and it was not harder to turn over than normal.

The truck starts easier if I hook up jumper cables and boost the battery with another vehicle.

I don't know what to do now. Does anyone have any ideas? I need the truck to get to work during the week but I don't want to just start changing out parts.

Thanks in advance.