16' Mercruiser 3.0L correct pitch

[stubby123]

I've got a few issues with my 1988 16' Edson.

I changed from an 18" aluminum prop to a 21" stainless.
WOT approx. 4000 rpm, valve were tapping and after
a short run at WOT lost power and bent a valve in the process.
I thought I had some cooling issues however temp at WOT was 140 degrees.

New head and valves.
21" prop, WOT max 4000 rpm. Engine seemed to labor
and could hear the valves tapping and again after a longer
run at WOT, bent a valve again.

I know I should be using either a 17-18" to get around 4800 WOT.

Is it possible to bend a valve with too great a pitch at WOT?

 

[hwsiii]

Re: 16' Mercruiser 3.0L correct pitch

Not really Stubby, you have an engine problem.


H

 

[steelespike]

Re: 16' Mercruiser 3.0L correct pitch

Are you getting a single bent valve, on the same cylinder?
was it a new head? and new valves and springs? or good used replacements?
Sure sounds like valve float,valve timing?weak/broken springs,how are the
push rods?Are the valves seizing,lifters seizing,Rockers?