No 1 cylinder is the one at the front of the engine, it's the opposite end to the flywheel.
Did you take my earlier suggestion and take the boat out for a long hot run ?
You may be spending money
Often engines that are only used for battery charging
while moored in the marina don't get up reach full operating temperature for a long enough period and some of the fuel injected is unburnt and washes the oil
off the upper cylinder walls and this causes the bore of the cylinder to get polished resulting in some dilution of the lubricating oil and lack of compression as the piston rings don't make a good seal to the cylinder bore.
There are 2 ways to cure this,
1,Make the engine work hard and it will cure itself over time.
2,Strip down the engine, hone the bores and rebuild.
If the engine is not used properly it can't work properly.
As long as the water from the injection bend cannot get back into the engine the exhaust bend angle shouldn't be a factor.