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Hello. My first post here and hoping to get some expert advice. I have an old Poulan walk behind with a B&S 100900 series engine. The starter rope pulls easily for first foot or so and then gets hard to pull. Sometimes I get a strong kick back that almost pulls my fingers out of joint. I've pulled the flywheel and the pin is in place and not sheared. What else could be causing this kick back problem? Thanks.

Is the blade on, and tight?

No, the blade is not on. It's my son's mower and he took the blade off. Does the blade being off make a difference?

Yes, on pushmowers they calculate the weight of the blade along with the pushmower's lighter flywheel, other devices have a heavier cast iron flywheel.

Putting a new blade on did the trick. Started right up. Thanks. One more question, please. Do you know, or where can I find, the torque pattern and torque ft/lbs on the cylinder head bolts, and the torque ft/lbs on the blade bolt? Thanks again. It's a B&S 10A902-2139 engine.

sumdumgai said:

Putting a new blade on did the trick. Started right up. Thanks. One more question, please. Do you know, or where can I find, the torque pattern and torque ft/lbs on the cylinder head bolts, and the torque ft/lbs on the blade bolt? Thanks again. It's a B&S 10A902-2139 engine.

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Briggs and Stratton Cylinder Head Torques

Personally, just Smurf them down tight and don't worry about it much, we aren't working on a Space Shuttle here!!!!

I've seen those torque specs and used them, but I can't remember where. I'll try to check on it. Personally, I think over-torquing is a problem. I have worked on a lots of mowers and trimmers and whoever torqued it was either very strong, or they used an air wrench! I've had to go and buy special extended ratchets and exact fit sockets (not the serrated ones) to break loose the nut on blades and such. When working on the engine, be sure and remember to use loc tight as well.

bigjck said:

I've seen those torque specs and used them, but I can't remember where. I'll try to check on it. Personally, I think over-torquing is a problem. I have worked on a lots of mowers and trimmers and whoever torqued it was either very strong, or they used an air wrench! I've had to go and buy special extended ratchets and exact fit sockets (not the serrated ones) to break loose the nut on blades and such. When working on the engine, be sure and remember to use loc tight as well.

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Yah, those torque specs are general, and I have seen lotsa overtorquing. I have also seen lotsa bolts that twist off when you use a hand wrench
or socket, but an impact will bring them out easily.

I never resort to Loctite unless there is a known problem....

Have to agree with Fish on this one. NEVER use loctite on any small engine nuts or bolts.

Thanks. I see where the cylinder head bolts get torqued to 140. But what about the torquing sequence? I know you're supposed to generally go opposite side to opposite side but I'd like to do it right.

A google or Bing image search will pull up a sequence for you.

BTW, those are Inch Pounds!!!

sumdumgai said:

Thanks. I see where the cylinder head bolts get torqued to 140. But what about the torquing sequence? I know you're supposed to generally go opposite side to opposite side but I'd like to do it right.

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Careful, say to yourself "inch pounds."

sumdumgai said:

Thanks. I see where the cylinder head bolts get torqued to 140. But what about the torquing sequence? I know you're supposed to generally go opposite side to opposite side but I'd like to do it right.

Click to expand...

This should help you out.

Rivets said:

Have to agree with Fish on this one. NEVER use loctite on any small engine nuts or bolts.

Click to expand...

Well, Donyboy73 uses loc tight on many of his videos. I don't use it lots, but do on engine bolts after changing out the rings, or such.

bigjck said:

Well, Donyboy73 uses loc tight on many of his videos. I don't use it lots, but do on engine bolts after changing out the rings, or such.

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Learning through blood, sweat and tears! lol

OK, which one of the cylinder head pictures in an earlier post would this picture look like? BTW, all of the bolts are same length. Inch pounds vs. foot pounds! That's a pretty significant piece of information. Thanks.

On the earlier chart, the top right one is the closest to yours, it basically hops from one side to the other, and is not hyper-critical on the sequence.

For others that read this, is 3 of your head bolts are longer, they go on the corner that the exhaust valve is close to, on this head in his pic,
it would be bottom right.

My last post to this thread. My Poulan mower is up and running. Thanks to everyone who contributed.

Well done, and thanks for letting us know.:thumbsup:

Hello--- First time here (and really sorry if I do this wrong).

This isn't a lawn mower question, but an engine question(s).

I bought an old generator (1970's ?) powered by an 11HP Briggs and Stratton engine. I started it before actually paying for it. Hard-starting, but it ran.

The generator-part was no good, I just removed and chucked it in the metal recycle. But no biggee-- I just wanted the engine anyway.

Got it home and the damn thing wouldn't start. Finally-- I did get it it to run ( for about 3 minutes), but kind of "rough" running.

As I said, it's an old B & S 11HP horizontal-shaft beast! I think it's an "updraft" carb setup. (whatever that is). Looks good on the outside (not all rusty/crusty).

It seems to be several things that I notice so far......

1. Gas "lightly" drips out of/ or off the bottom of the carburetor. Pulled the air cleaner, looked down, and looks like there's some gas in the bottom of the carb. Don't know what causes it, or if it's part of the non-start problem, it doesn't leak that much, but it just isn't supposed to be doing that.

2. Occasionally (maybe every 5th pull on the cord?)-- it just about rips my fingers off pulling the cord and handle back-- hard (and suddenly). Hurts like crazy. Then, for the next few pulls it seems OK. Then out of the blue-- does it again. Startling for sure-- and hurts like hell.

3. On a few occasions, also, (while trying to get it started), it would backfire.

4. I pulled the sparkplug out and it was dark black carbon-y, but dry/ not oily. Wire-brush-cleaned it well and blew it out w/ air compressor, and put it back in.

5. When I did finally get it started, it made a helluva scraping noise (sounded like it was in the recoil-spring area-- LOUD). Gave a little pull on the pull rope and it seemed to go away. (NOTE---- prior---- , I had the recoil cover off and WD-40'd the recoils/spring assy, and it was free and turning easy (it had previously been "draggy" and sort of slow- if at all- to get the pullrope and handle all the way rewound up tight. Anyway-- it seemed to be fine, when I put it back together).

Anyway-- I've made a pest of myself here as a newbie, and am sorry for that!

This big-ol' engine is a beast (it's hopefully destined to power a small bandsaw mill!), and it's just a shame to think to just chuck it in the metal recycle if it can be brought back to life! My hands are aching from the handle being ripped out of them--- instantly--- while working hard to PULL the rope--- I won't be able to keep the engine if I can't fix that-- my hands won't take it.

There are always a few of these older engines popping up "out there" (on Craigslist, etc), for maybe $100-200, so throwing a pile of money at it at a professional engine-repair shop is just not feasible.


Anyway-- and many/any thanks in advance------ has anyone out there ever had these kind of symptoms? I'd just hate to chuck this bad boy.


Thanks-- MakMak