Oh darn. Rebuild time I think. pro mac 10-10 automatic

[strad]

Yeah I think I've got some major issues with my saw. Looking at the cyl. walls through the intake port (can only see exhaust side walls) there is what looks like some pretty good scoring. Funny enough I looked at the exhaust side of the piston recently (through the exhaust port) and while not new looking it didn't look as bad as the walls.

I really think I must have a crank case leak b/c a: the saw idles faster than it used to (blade spins at idle -- didn't used to, carb has not been touched). I also have a major leak from the oiling system (which I understand is run by air pressure from the crank case). The leak is not from the gasket around the tank cover. So I thought I'd disassemble and see what the inside of this little engine needs.

Anyways, first question is, how do I remove the flywheel nut and clutch nut? Impact? Or how do I hold it still while loosening one side, and then the other. And then down the road how do I torque those things properly?

I've done head gasket replacements and major suspension work on my BMWs successfully, so I'm used to working carefully and precisely. But I've never worked on one of these lol! I don't need to use the saw very often but I'd like to have it in working order.

 

[BrocLuno]

Go slow and be careful. Get (or make) a piston stop which screws in the spark plug hole and stops the piston and crank so you can take of nuts, etc.

 

[fearofpavement]

A small impact is probably the easiest way to get the nuts off the clutch and flywheel but make sure you know whether they have left or right hand threads. Most clutch nuts have left hand threads and flywheels right hand threads but I am sure there are variations. It is very easy to bugger something up so do research first and then apply the wrenches.

If the saw needs a lot, it may be cheaper to replace it with another 10-10 than to fix it. I bet you can get any parts you need for it though as they made a gazillion of them.

 

[strad]

Haha if I have to replace it, I'm getting a pro mac 700! Hope to not have to replace it though. Our family has had it since new.

Edit: so I know I'm going to need the piston stop tool. What other tools am I going to need that I'm not likely to have? I have a torque wrench that'll give me inch-pounds, so I'm covered there. I'm also well covered in the basic, common tool category, plus a bunch of special tools that make it easier to work on my BMWs. But I don't have stuff like any of the special tools mentioned in the Mac shop manual. To remove the con rod from the piston for instance. What do I "need" and what would be nice to have? I'd like to buy/order everything this week so I can disassemble next week.

 

[fearofpavement]

If you use an impact, do not use a piston stop. It isn't needed and you may damage something. Also, you can use rope as a piston stop so you don't need to buy one per se but....

 

[cpr]

Yes, use rope, not a stop. The only thing a stop is good for is finding TDC. I'd say there's something amiss. There shouldn't be bar oil leaking from anywhere, but the front cover given the design unless something is cracked.

 

[dce1843]

the bar oil leak could be your manual oil pump on top.