[anton vella]

Hi,I have recently bought a boat with 2 volvo 4.3 GL engines,and 1 of the engines is running 1000rpm slower than the other, and slower than it is stated by the manual.The same engine have rebored recently.I carried out a compression test and the result is poor.I removed the heads and checked the seatings which were not that poor state, howerver the bores appear to be glazed with small patches as if there was water for some time.The risers were worn out and replaced so possibly water leaked before.My concern now is that in the chamber and valves have a redish appearance and was thinking if it is possible that carbon didn`t cover the water deposits left before the risers were replaced, or if I still have a water leak.
If I have a leak from were is it coming?Both inlet and exhaust ports are clean,just the usaul carbon coating on the Exhaust.Since the risers were replaced the engine worked for about 10 hours.

Many thanks for reading and further thanks for replying.
Anton.
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hello there.

[MikeW]

I would have the manifolds pressure checked to make sure they are not leaking.