Originally Posted by Impressions Landscaping
Funny you ask about the compression test. I did one tonight, since the motor has around 1700 hours on it. The front cylinder has around 90 PSI and the rear has around 140 PSI. The front plug has burnt up oil on it, so I cleaned that, and also checked the rear plug which was fine. Obviously the motor needs a ring job. The carb is still screwed up however, since cleaning the plug did nothing to fix the issue with the idle. Unless you think otherwise.
Im surprised it ran this long...optimum compression is 180 psi...
130 to 150 will run somewhat ok...as long as there is not more than 10 psi difference between the cylinders..
With 50 psi difference...and the low side at 90...you have a bad valve or a blown head gaske that sounds like air brakes when you turn the engine off.
The wait is over...pull the head...