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1996 mercury force 120hp compression
- Thread starter Accipiter
- Start date
RedBarron55
Jet Boat Addict
- Messages
- 280
- Reaction score
- 100
- Points
- 122
- Location
- Navarre, FL
- Boat Make
- Jetcraft
- Year
- 1995
- Boat Model
- Other
- Boat Length
- 16
150 - 125 = 25 psi
15% of 150 is 22.5 psi so the numbers are within the acceptable range.
I would run the engine to warm it up and then check again
10% would be better match.
There is a slight designed in difference between the cylinders
With a charged strong battery all plugs out with the throttle wide open.
Crank the engine over the same number of times.
The gauge should peak out and hold the max pressure in the same number of revs.
Late engines had a compression of 145 top and bottom and 155 in the center.
If this is in the jet boat if it pulls 4800 - 5200 rpm then run it and don't worry about the difference.
A decarb might help.
Do you own the boar or ding a pre buy inspection?
15% of 150 is 22.5 psi so the numbers are within the acceptable range.
I would run the engine to warm it up and then check again
10% would be better match.
There is a slight designed in difference between the cylinders
With a charged strong battery all plugs out with the throttle wide open.
Crank the engine over the same number of times.
The gauge should peak out and hold the max pressure in the same number of revs.
Late engines had a compression of 145 top and bottom and 155 in the center.
If this is in the jet boat if it pulls 4800 - 5200 rpm then run it and don't worry about the difference.
A decarb might help.
Do you own the boar or ding a pre buy inspection?
