Stihl chainsaw almost locked up-?

[jmc]

Hello,

I can barely pull the starter cord on my small Stihl (model 009). It will turn over once with a hard enough pull. Air filter is clean and it turns freely with the spark plug removed. Worked ok the last time out- maybe 3 yrs ago. I was hoping to use it in the morning. Any suggestions?

Thanks,

JOhn

 

[RalphVa]

Did you try it after you put the plug back in?

What'll lock them up is fuel sucked in and attempt made to compress it.

Be sure you're trying to start it with the throttle locked on. If the lock doesn't work, tie a cord to lock it full open. Two cycle engines have got to have the throttle full on to start properly.

The routine usually is lock on throttle. Pull 2 to 4 times with full choke until it fires. Then about 1/2 choke, pull, and it starts. Use the same routine with my 2 cycle grass whip.

My 009L still works after more than 35 years. Think I bought it in 1972.

Sometimes, a shot of starting fluid into the air cleaner hole is needed but usually only on very cold days.

Ralph

 

[jmc]

Hi Ralph,

I put the plug back in and it still pulls hard and just makes it thru the compression cycle once. And that's with the throttle locked open. I'm pretty sure it has something to do with the cylinder being completely sealed during one phase of the stroke.

Thanks,

John

 

[jiNpa]

Hi Ralph,

I put the plug back in and it still pulls hard and just makes it thru the compression cycle once. And that's with the throttle locked open. I'm pretty sure it has something to do with the cylinder being completely sealed during one phase of the stroke.

Thanks,

John

Is it a new plug? Its not too long is it? Just a wild guess.

 

[jiNpa]

Hi Ralph,

I put the plug back in and it still pulls hard and just makes it thru the compression cycle once. And that's with the throttle locked open. I'm pretty sure it has something to do with the cylinder being completely sealed during one phase of the stroke.

Thanks,

John

Sounds like the piston is hitting the spark plug. Did you recently replace the plug? If so make sure its not too long.

 

[20 20]

If it pulled over easy with out the plug then jammed again with it I'd take a hard look at the plug. I'd also stay away from starting fluid, not really a good solution to any engine.

 

[Treemonkey1000]

Make sure it isn't your rope pull binding. If the case is cracked or the pulley is binding that will make it hard to pull. Been there done that. That is a pretty small motor so it shouldn't take much to spin it under normal conditions. With the plug out and it still binds then I would look at the rope pull portion. The pulley holding the rope can get dirt and grit under it and bind up pretty good. Just be careful if you get into that as the recoil spring can get you. Plus putting that recoil spring in is more fun than a Proctologist visit.

 

[Gator6x4]

Hello,

I can barely pull the starter cord on my small Stihl (model 009). It will turn over once with a hard enough pull. Air filter is clean and it turns freely with the spark plug removed. Worked ok the last time out- maybe 3 yrs ago. I was hoping to use it in the morning. Any suggestions?

Thanks,

JOhn

Remove the muffler and clean the exhaust port. It sounds like carbon is blocking the exhaust port and not allowing the engine to breathe. When the spark plug is out, the engine will spin freely because it can breathe. Use a sharp pointed wooden stck to clean the ports, do not use a screw driver. Also when cleaning the ports, pull the start rope and move the piston away from the port. The muffler can also be stopped up causing the engine to be unable to exhaust air. So, if the exhaust port was clean when you removed the muffler check the muffler for an obstruction.

 

[jmc]

OP here. Thanks for the responses. It's definitely not the plug or pull cord. You can here air/gas escaping very slowly on the compression stroke. I had started to remove the muffler but it's got a metric torx screw deep in a counterbore, probably tighter than the dickens. I'll do that as a last resort since it seems like a plugged exhaust would have been noticable the last time I used it.

In the meantime, as I look down thru the carb throat it seems like I should be able to see into the cylinder at some point in the cycle. I can't but there is something relective down there that deflects a little at one point in the cycle. This motor may have a reed valve stuck in there someplace, which would be consistant with not using it for several years and not draining it of gas before that. Any comments on that?

Also, my can of carb cleaner does not recommend squirting it into the carb if the engine is not running. How do I clean this up if there's varnish in there?

Thanks,

John

 

[newbury]

Take it to http://www.arboristsite.com/, they are the experts.

Lot more chainsaw users.

 

[Diamondpilot]

Others gave good suggestions but I would check the pull rope/clutch area.

Chris

 

[Carykong]

I have gotten by old mecury 25hp outboard going after sitting for over two years with old gas with Sea Foam Gas additive. Just a few spoonfuls in the bowl and the remainder in the gas tank. Ran just like the day I bought it new in 1988,

 

[Gary Fowler]

If it spin freely with the plug out but not when it is in and you havent changed out the plug for a longer one, the the problem can only be one thing and that is the compression is building up with no where to go, Pull the muffler and check the exhaust reed valves. Maybe a dirt dauber plugged up the whole thing. It almost has to be in the exhaust not getting out.

 

[DennisMI]

Could it be a sheared flywheel key?

 

[tree farmer]

I'm thinking rust or other corrosion has formed on the rings or cylinder wall, especially if the saw was stored in a damp area. If that's the case, I would pull the plug and shoot a little penetrating oil in the spark plug hole, then turn the engine over a few times with the plug out. Now tip the saw over and dump out the cylinder. Check the appearance of what comes out. If that doesn't work, you're gonna have to pull the head....Dan.

 

[BigE_]

My Stihl 036 was doing that for a while, really hard to start, really hard to pull the cord. Almost hurt to pull the cord. This was after leaving it sit with gas in it for 4-5 months.

I dumped all the gas out, bought fresh premium, mixed it with Stihl oil, finally got it running and ran it hard, never had any problems with it after that. Maybe I just got lucky, though.

 

[Dave5264]

Not familiar with this particular stihl saw, but is it at all possible for mice tohave gotten into the muffler?

it doesnt take much for them critters to get in , if you can put a pencil thru the gap/hole in the muffler /exhst opening, a mouse can get in.

id take the muffler off, and see if it turns over

 

[BXpanded]

If I understand, the rope is very hard to pull.
Unless I missed it somewhere, the op hasn't said...
Is the rope hard to pull when the sparkplug is removed?

If it is, it's likely rust on the cylinder wall, assuming that engine has an iron cylinder liner.

When you look down the carb throat you're probably seeing a reed valve. If it moves, it isn't stuck. A stuck reed valve (in the unlikely case that it could stick closed) would make it easier not harder to pull the rope.

 

[Ford850]

OP said it was easy to pull with the plug removed. As some others have suggested, check the muffler. Mud wasps get into the muffler and build a mud nest plugging the exhaust. I've had it happen to me, and I suggested it for another poster some time back and it was the cause in that situation too.

 

[woodchuckie]

I don't know what the problem is with mine but at times after it's set for a while it's hard to pull like the exhaust valve isn't exhausting. I take the plug out and it's easy to pull. I put the plug back in and it pulls normal and runs like it should.