Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I'm hoping I can get some help from this forum....or at least your opinion.  Three years ago when I was transferred to Connecticut, I purchased an old (mid 70's, model 910995) ariens snowblower that I found on craiglslist.  The purchase was alittle bit nostalgic, as it was very similar to the machine my dad had and used all while I was growing up, and worked great for him.  For the past three years, no problems....quick to start up, and threw the snow with ease (even the heavy crap we sometimes get in CT).  This fall, I changed the engine and gear oil, filled up with fresh gas, and gave the carb a couple of shots of cleaner while I let it run.  It ran for about 15 minutes with no problem and I was confident it would be another good season.  During the big snowstorm we got over Christmas, it did not go well.  The blower worked for about 10 minutes with no problems, then shut down.  No sputtering, or sounding like it was running out of gas, just died. I restarted it with no problem, and it ran another 5 minutes, then the same thing....died.  I continued to clear the driveway like this, a couple of minutes of running, then die, then restart.  Sometimes it would die when under a heavy load, other times not. 

So a couple of questions:

     -Any suggestions on what I can do to improve/fix this problem?  The way it runs fine, then shuts down without warning, then restarts easily makes me think its more spark then fuel related.  Any thoughts?  I haven't done much work on small engine other than the normal mainenance, but am reasonably mechanically inclined. 

    -Unfortunately, I have no way to bring the blower to a repair shop.  My local shop will pickup/dropoff for $75.  Add in another $100 or so minimum to repair, and I've spent close to 200, and still have a 30 year old engine.  Looking online, I can get a replacement motor that I could put in for about 250.  Doesn't this make the most sense?  I'm pretty confident I can swap out the old engine, less confident of my troubleshooting/repair abilities. 

Thanks for reading, and appreciate any advice.

I found a post on another forum where someone used a section of PVC or deep socket to install the seal, both of those seem like good substitutions for the factory tool.  Still need to know about timing -- if the stator comes off to replace the seal will i need to redo the timing?  Can I mark the position if it currently mounted and reinstall in the same spot, or will that not sufice?   thanks.

The flywheel/rotor/stator has a keyway right?  If so, when you put the flywheel back on, it should be set properly.  As long as you put the points back the way you found them, and have them properly set, you should be good to go.  Did you ensure the points follower was resting on the top of the cam lobe when you set the points?  If so, they should be OK.  Let us know how it goes.    

I think he's talking about the stator as in the holder for the points. 

I've had them off and would not rely on a pencil line.  Too much of a pain if you get it wrong.  To easy to get it right.  Well not exactly easy but easy enough.  You can set them with a multimeter.  At least for me that works best.   The procedure has been described many times in pior posts.  It's in the Tecumseh 3-11 L-head manual which is free online.  For the BTDC distance given in the explinations you can eyeball that or if the head is off measure directly using feeler gages.

trouts2 wrote:

Right -- maybe I described it wrong.  I've read the procedure in the manual, and the part of concern was finding BTDC and the use of the dial indicator.  Once you get that, your right, the rest doesn't seem bad.

   The BTDC can be gotten right as I mentined but you can use just TDC and that will work well enough.  If you want it a hair better you can guestimate  someplace between BTDC and TDC and you'll also "well enough" plus.   Friiy once said about, "It's not a funny car".  True but I don't know how much would be lost by going TDC instead of BTDC.  If anyone knows please post it.

How many degrees or mm before TDC is the recommended setting?  If you know how many mm before TDC,  you can take the head off and use a caliper to measure where TDC is then back the piston down the number of mms to achieve the correct setting.  It's not really that complicated.  Especially on an old Tecumseh flat head. 

trouts2 wrote:

I'm assuming that "BTDC" means "before top dead center".   If it is, this is the point where maximum ignition advance is set. 

In an engine with static advance, (as in an engine with points), the position where the advance is set, will be where the piston is located when the spark occurs to ignite the fuel in the combustion chamber.  A static advance setting is usually a compromise to allow for a certain range of rpm.  More advance at lower rpms will generate more torque but the same advance setting at much higher rpms will be detrimental to the engine, both power wise and mechanically.   In a relatively low revving four stroke engine, such as used in OPE, it is desirable to have maximum advance as prescribed by the manufacturer.  It will make a difference in power.   While I do most of my engine work on two cycle engines, the principles of advance are the same.

You should set the piston at recommended BTDC for maximum allowable advance.  In this case, I'd rather have a bit more advance than not enough.     

borat wrote:
Any guestimate on how much?

trouts2 wrote:
Hard to say, but I'd bet that It will be noticeable.  Particularly torque. 

With high performance two cycle engines, some guys like to flirt with maximum advance due to the additional available torque it provides at lower rpms.  The downside  is that high rpm power and reliability are compromised due to too much advance.   I equipped my modified Yamaha two stroke engines with programmable dynamic ignition timing.   Maximum advance is 24.3 degrees from 500 to 4500 rpm.  From there, as rpms rise, I set the computer to retard advance values progressively until its at 16.5 degrees at 9500 rpm.  That way, I get all the low end torque due to lots of advance and top end power and reliability by retarding it.  If I were to spin the engine that fast with 24.3 degrees of advance, the engine would detonate (pre-ignite) so bad that it would destroy itself.   

Correct advance is important.  Particularly in an OPE engine where torque is paramount. 

>>static advance, (as in an engine with points)

Does that also apply to SSI?

Interesting on the adjustable.  What's the name of the device.  If I google around I'll get all car stuff.