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.

Check the wiring going to the kill switch and if there are any safety switches.  Jump them out and see if it stays running. If so then you can fix the switch.,  Next check the coil and points. Start with the easiest first.

Loosen your fuel cap to allow air into the fuel tank while it's running and see if the problem goes away. 

If the machine has points and condenser, you may have a bad condenser if it's not fuel related.  A faulty condenser will work until it heats up then it shuts down.

Thanks for the replies and suggestions so far.  I was aware of the issue with the fuel cap, so I loosened it after first time it died.  No key on the blower to kill the engine, but I'll look it over to make sure nothing else that could shut it off. 

I got the manual off the internet, and will start checking out the rest of the things.  I forgot to mention in my originial post, the compression was 80psi when I checked it dry.

Thanks again

Could it be a carb problem?

Like something loose in the bowl that occasionally vibrates over and clogs the jets.

Or a stuck float getting stuck closed sometimes.

Or while we are at it something in the bottom of the tank.

Shryp:>>Like something loose in the bowl that occasionally vibrates over and clogs the jets.

That happens to me all the time even after cleaning a carb and flushing the tank and line several times.  Very frustrating. 

Remotely possible to be a plug but usually requires a wait time for the plug to cool.

Could be a needle adjustment or sticky needle seat but most likely what Shryp said.   I doubt it's compression related. 

On the 80 reading.  Compression readings are almost a black art.  For that old engine 80 is not so meaningful.  It could belch oil under load or perform very well with an 80. 

Don't know if those machines already had oil sensors but maybe an intermittent oil sensor issue cutting the ignition ??

Thanks for the replies, heres an update after I had a chance to look at things last night.

First off, when I opened up the stator, there was oil at the bottom.  not alot, but enough to put a film on all the parts.  Based on how hard the flywheel was to get off, i dont think anyone has been in there for a while, so hard to tell how bad the leak is. 

The condenser was if not original, very old.  the points looked ok, but needed to pickup some feeler gauges this morning to check the gap.  connections had a reasonable amount of corrosion, plus crud due to the oil leak.  found the kill line, which runs off of the throttle position.  wire sheath looked worn in areas.  so heres the plan:

     -clean all parts to remove oil.

     -replace condenser, and regap points

     -replace kill line with new wire

     -clean connections with emory cloth

A couple questions:

     -are the 3 tools shown in the manual (oil seal driver, protector and remover) required to replace the seal?

     -if I remove the stator will I need to retime the ignition?  reading through the process, this is something i'd like to avoid if possible

I'm feeling optimistic that fixing these things will improve how the engine runs (and like I said originally, it ran well up to this year).  If it doesn't do it, on to the carb....

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.

trouts2 wrote:
Not sure what SSI is. 

I have an Echo chainsaw with automatic ignition advance.  The acronym for that is SAIS ( Slope Advance Ignition System automatically    
adjusts ignition timing for optimum performance).  Is SSI something similar.

The units I use on my Yamahas are made by a European outfit named MZB and Zeeltronic.  There are three components:  the dynamo, the controller and the programmer.   All of the original electrical generating and ignition parts are eliminated and the new stuff replaces it.  If you just go with the dynamo and static ignition system, you end up with an analog system.  Add the digital controller and now you have programmable ignition which is programmed by plugging in the programmer and inputting the desired curves.  

Here's a couple links showing the MZB system and Zeeltronic controller:  

http://www.powerdynamo.biz/eng/systems/7106/71067main.htm

http://www.zeeltronic.com/page/vcdi-04.php
  

SSI is just an abreviation for solid state ignition, electronic ignition.

OK on the auto advance modules.  After looking at those I remembered looking at them before I think after you mentioning them in another thread some time ago.  Nice for peaking a Yamaha bike but a bit over for a snowblower. 

This brings up a constant confusion so I post a seperate thread.

Most definitely not needed on a snow blower.  Not enough rpm to be concerned about. 

However, proper advance setting is important if you want to get maximum power and torque from the engine at speeds under 4000 rpm.

Just wanted to give a quick update to those who helped me. We got buried in 2ft of snow last night. Ran the machine for 3 hrs this morning and not one shutdown. Earlier I had replaced the condenser and the kill wire, and cleaned up some oil on the points. Very pleased. During the last hour or so, it started to surge alittle bit, and the power seemed down. Going to clean and reseal the carb and see if that fixes it. Also the muffler blew out. Alittle unsure of that repair as the remaining pipe seems pretty fused to the engine. I'll worry about that another day, now time for a beer.

Nice going, tune-up, crab cleanup, maybe a new seal and you're running.  At least for me three hours would be way over pushing that engine. 

Probable some residual crud from the tank or line.  If you can get a cheap Briggs inline filter and put it close to the carb intake if it will fit.  I bought a bag of 25 but I hardly get a chance to plant them due ti space.

The 910995 is the bucket model.  The machine model is at the back base.  The engine number should be stamped on the top of the cowling.  So not sure what engine you have but likely the H70.  Some people claim it to be one of the best engines Tecumseh ever made.