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Reduced compression

andyl127

New member
"my motor is a 1994 yamaha 150

"my motor is a 1994 yamaha 150 saltwater series. the fuel gauge failed and i ran out of gas. after refilling, the motor would not get over 4200 rpm at full throttle, made 5500 rpm an hour before. Changed water seperator which was really dirty, checked engine mounted filter which was very clear. Also checked compression, which are all six cylinders low at 105 psi--all exactly the same. I would have thought compression would go unequally between the cylinders, unless something was preventing all six cylinders from making 125-130 psi. Any body have any idea what else can keep the cylinders from getting full compression?

I am no expert at this---appreciate any help. thanks."
 
"Battery condition will effect

"Battery condition will effect the readings, so will a different compression gauge...however i wouldnt be worried about the compression figs they are fine."
 
"Running out of gas can cause

"Running out of gas can cause problems, especially if you are running at high rpms when it happens.

V-6 engines can be very vulnerable when this happens, depending on exactly how the fuel is distributed. A vertical rail, feeding stacked carbs, will usually cause the top carb to run out of fuel first. The engine can continue to run, and damage can result.

Fuel injected engines probably would not experience this."
 
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