Re: 4.3L Mercruiser Knocking?
from your post i remember when it was me asking these ???
compression test, is not hard to do if you get a service manual for your engine , you will know how to do a lot of things on your boat soon.
1 get a compression guage you can rent one from autozone
2 take all the spark plugs out
3 unplug the coil wire and grount it on the engine block .
4 screw in the fiting on the compression guage in the spark plug hole, the end has threads just like the apark plug it self.
5 crank the engine over antil the needle on the guage goes no more .
6 write down the result on all the cilinder.
if all cilinders has over 125 psi the engine might still have life.
if you have a real low reading on any cilinder, spray some oil in that cilinder and test it again,
i am not a great tiping guy like some on this forum, i am just trying, but with the manual it will tells u everything.
post your result here when you r finish , guys here will tell u what the trouble is.
