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

I found that my "new to me" Toro 824 Power Shift blows some blue smoke after I come off idle to full throttle.  It only lasts for a second or so.  I havent ran it long enough yet to see just how much it is burning to a tank of gas  Is there a way to determine if its rings or valve guides?  What is the procedure for checking the compression and what are the specs for it?

Warm engine, shot of oil in spark plug hole and pull it thru a few times?  I added an ounce of Seafoam to the gas and a few ounces of Marvel Mystery oil to the crankcase so I can try and loosen up any possible stuck rings or other Mystery Gremlins.

Thanks
Packo

Compression tests are to be done with a cold engine.  No oil in the cylinder.  Connect the compression tester and use your electric start if you have it and turn the engine over  5 or six times watching your meter to see where the needle stops.  If you don't have electric start, do the same thing with the pull start.  Five or six good pulls should give you a reasonable reading.  It should bump up the compression on each compression stroke until it has achieved maximum compression.  That will be your reading.   Not sure what the compression is for your engine but anything over 100  should be acceptable with 100 being close to the lower limit.   

A bit of occasional blue smoke isn't an issue.  I operated some OPE engines that puffed blue every time I changed the throttle setting.  As long as the engine is making good power, and not constantly blowing blue smoke, don't worry about it.  Keep your oil clean and check the level frequently until you get a feel for it's oil consumption.   Check it before every use.  I recommend synthetic oil for cold weather equipment.      

I just read  Chiltons small engine repair and it says to warm the engine up to lubricate and seal it before doing a compression check. 
Packo

   Over the last year talked to a number of dealers, perused the net and in general the low number for a healthy engine is all over the place, 50, 60, 70, and 90.  This is the first time I’ve seen 100 as a motor to stay away from.

 

   Friiy said last year the tests were not so reliable and later explained about compression release which at the time was new to me.  I’ve since found there are 4-5 basic mechanisms for compression release and not all have the same spec for psi release.  For example there are many late 90’s early 2000’s that release at 45.  No matter the amount of pulling or time on the electric start button the needle will no go past 45.  The engines were fine and perfectly robust.  With one of them I came close to beating my nemesis, a feared Honda track. 

 

   Some motors get a low compression test reading but do fine on a leakdown.  If an engine gets a high reading then it’s probably ok.  But a low reading does not necessarily KO the engine.  It could be the compression release on that engine won’t allow a higher reading.

 

   I’ve had a few motors that tossed fine with low compression.  Most of the older machines around in good condition like Ariens and Toro machines have worn motors but still good for many years of use.  Some still run, don’t smoke but can barely toss.  One older Toro I had with a compression test of 90 belched oil when slightly loaded, 3-4 inches of snow. 

 

   For a while I was taking compression readings on every engine I got in and keeping track of them.  It was just about impossible to count on any reading except high readings.  During the winter with snow around you can take a reading then go toss with the machine to see how it does.  During the rest of the year it’s impossible to put a load on an engine.