I'm replacing a Yanmar 1GM10 with a Beta Marine 14. Existing raw water hoses, from the sea**** to the filter, and the filter to the water pump, are 1/2 inch (12mm). Beta Marine specifies 3/4" (19 mm) raw water hoses for their engine sizes 10 to 45 hp.
Given that the largest of the engines in this range is more than three times the displacement and power output of the 14, is it necessary to upgrade to a 3/4" raw water system?
19 mm hose cross section =~ 283 sq mm
12 mm hose cross section =~ 113 sq mm
The ratio of the larger hose cross-section to the smaller is 2.5 If the cooling capacity of the raw water system is roughly proportional to the cross-section of the water column, then the smaller, 12 mm raw water system should be more than adequate to cool the Beta Marine 14. I ordered the deluxe control panel to be sure that I could monitor engine functions more accurately.
Is the use of the existing, smaller raw water intake likely to be a problem, and will it void my warranty?
The simple answer is that you need to change the intake thru hull to a 3/4" or 1". This has everything to do with allowing the correct water flow over the heat exchanger to facilitate the heat transfer.
Failure to have the correct intake will likely cause run hot problems and you will have caused this which will not be covered under warranty.
