Cylinder Compression Question

[unspin]

Hey everyone!

I purchased my first boat a month ago and have been going through the motions learning all the things
My engine is quite old (1970 Mercury 800 80hp) and i have a question about a compression test i carried out recently

It was a dry/cold test and i had the following readings on the four cylinders: 155, 155, 135,130
The engine runs a bit rough (jumps around a bit when idling and stalls when i put it in gear if i dont give it enough throttle)
She seems okay at speed though and i've had her running at 35/40 mph, although she seems to lose power after a few hours in the water (have a hard time getting on plane with a few people in the boat)

Is there anything i should be concerned about with these numbers? I really dont have it in me yet to rebuild the powerhead
Going to rebuild the carbs in a few days though, hopefully that will calm her down some

 

[Mi duckdown]

Have you changed The water impeller? You may be over heating.??? Those compression numbers are fine

 

[Faztbullet]

Your compression is unbalanced, That motor has high dome pistons from factory and will have 145+ compression. The lower cylinders are low on compression. Check #3-#4 plugs for rust and water droplets as these are bad about lower seals and exhaust baffle leaking internally.

 

[unspin]

Just installed a new water pump yesterday, seems to be pushing water well
The old one was munched but functional, just waiting on the lower unit to come in before i finish the job