Small Engines (Lawn Mowers, etc.): follow up question, craftsman snowblower, compression gauge

Question
QUESTION: As a follow-up to the question below, would it make more sense to do a
compression gauge check prior to rebuilding the carb?  Wouldn't this tell me
if the valves or rings are shot on Tecumseh Model H60-75296H?

I just got an older craftsman snowblower model 53682241 with a Tecumseh
Model M60-75296H off of someone.  I have no idea how old it is because I
can't find the model numbers anywhere online.
I had a problem getting it to run without the choke.  Within a few weeks
(couple snow storms) it got worse.  I checked the oil and found that it was
really low.  I added some and then checked the spark plug and adjusted the
screw on the bottom of the carb 1.5 turns out.  It ran better but then was
sporadic again and would sometimes run great for a few minutes and without
warning it would die and only run at 3/4 choke.
As I tried to restart it it started to run at 3/4 choke and then a steady stream
of oil began pouring out of the crankcase vent.
Is the engine blown or should I try rebuilding the carb to see if it helps?


ANSWER: Why yes of course, who told you to just rebuild the carb? I'm sure it wasn't me, I see this is a follow up question. It only takes a second to do a compression test, especially if your blowing oil out the breather, and your low on oil. No sense spending money, and time rebuilding the carb to find the motor has oil blowing by the rings, and is shot. Had you not mentioned to me the oil situation I would have said without doubt you need a carb rebuild, I still believe you do for the running issue. But first make sure the rest of the engine is ok. Compression on that should be around 90-120psi..Tom

---------- FOLLOW-UP ----------

QUESTION: Tom,

I checked the compression and it holds steady at 65 psi.  That is lower than
the 90-120 you mentioned, does that low of a pressure concern you?

Also, I check the crankcase vent and the valve just consists of a thin flexible
sheet metal which flexes with either positive or negative pressure.  I didn't see
any obstructions or wear marks that interrupt its travel.


Brad

Answer
Yes that compression is a bit too low.....Try squirting about 8 squirts of oil in the cylinder in the spark plug hole, re insert the plug and retest it, if it comes up it bad rings, stays low it's with in the valves or head gasket...I think it will come up, and be bad rings...Tom