Mercruiser pitch help

[piratos]

good day all friends

thank you very much for all help
I Bought new prop is 16x13. I cleaned by hull now ı run 29knots it is very good for me,
but I check three times first start my engines and ı saw 80degree engine temperature I going to the beach for swimming 2miles away
my engine is max run 17knot when Im going,I stay 1 or 2 hours in the beach when I return to our marine, I run 29knots
I dont understand what is it?why our engine is not running 29 knots when I start my engine firstly,is it to do with the engine overheating
can you pls give information?

How are you meassuring the speed ?? by gps or by log ?
4600 RPM by 29 knots ??

 

[UTKU]

good day

I meassure by gps

My rpm is 4300 ı dont think so my tachometer is good working or not(I HAVE A 4 PERSONS INTHE BOAT)

but when ı return back from the beach I saw this knot

I load the youtube now pls check the video yesterday I record it then I return back from the beach

https://www.youtube.com/watch?v=ySSWrg9A7u4&feature=youtu.be

 

[TheOrs]

my engine is max run 17knot when Im going,I stay 1 or 2 hours in the beach when I return to our marine, I run 29knots

I dont understand what is it?why our engine is not running 29 knots when I start my engine firstly,is it to do with the engine overheating

I think you have an engine problem. I have had similar problems with my boat (5.7l V8 - 8.5m). Twice I have cleaned inside the distributor cap and made the boat go faster.
I suggest you check the engine: Spark plugs, distributor cap, plug leads, timing, carburettor etc.