compresion

[spareparts]

cehck it with another guage, I have four or five compresion guages, teh most expenisve one I own reads 10 psi low, the cheapest one reads 5 psi high( I checked than against a high doller set of liquid filled German manufactured pressure guages). Usually if they are close to each other, they are OK. I've never seen an engine equally worn out on all cylinders, usually, one cylinder lets go first. But I guess it cousl happen. Take the boat for a spin, see if it turns up rpm(check your tach also)