[QUOTE=brettw;3308435]Just did a cold engine compression test on my Yamaha F50 ,2002,
Results were frightening
Cylinder 1 55
2. 56
3. 55
4. 63

Added oil to cylinders
1 64
2. 56
3. 60
4. 66

Should be 110-120?

Symptoms, mostly hard to start
Easier to start out of water
Weak hole shot
Runs well once going

Ideas ?
Thanks


Sounds worn out to me. Just because the compression is so close to each other. I would think the oil would had gotten you higher.
Have the valves been adjusted? Should be about every 100 hrs according to manual.
If you are close to Lake Wylie I have a Mac Tool compression tester I can check it for you if needed.
How many hrs do you think is on the engine?
Also has it been using any oil lately ?. If it were a 2 stroke, which it is not the first thing I would check is the exhaust to see if it is stopped up.
However if it is using oil there is still the possibility of the exhaust being stopped up.
I just not sure how the exhaust would run the compression down. Just saying.
Also. Has the timing belt been change, if has it run right since?