I had same engine/prop/boat and same feeeling. I tried to decrease pitch (approx. by 1"") and I did get some rpms back, but I lost a lot of cruising speed. Before change I was runnign about 17 Kn at 3400 rpm, after that 16 Kn at 3500 rpm. I will test in next few days a 4 bladedc 17*21 prop, and we will see how it goes.... What is your current cruising speed and rpms ?. Also, I am thinking of fitting QL trim tabs in order to pu bow a liitle bit down, because my 695 feels a little bit stern heavy. Do you have same experience ?
Since posting seem to have a bigger problem the engine has developed a knock which is especially evident above 3,000rpm with the engine loaded, however no loss of power. Checked all the obvious injectors, timing as sounds like fuel but all check out OK. NOW AT A BIT OF LOSS. Typical speed with the current prop is 3,000 rpm 14 knots, 3,400 rpm best cruse 17 knots, 3,600 (volvos rec cruising) 19 knots noisy, WOT 3,800 22 knots maybe little more on a good day. I have checked with Jeanneau and the prop is correct at 19*21 3 or 4 blade however a Antares 710 has the same underwater profile and engine runs on a 3 blade 19*21 and will give the same performance at a higher WOT 4,000 22knots. Aqua quad the prop manufacturer however recommends that the 4 blade prop should be 1inch less pitch than if you were running a three blade. The boat needs to run in excess of 16 knots to perform properly. ANY HELP ON THE ENGINE NOISE WOULD BE MUCH APPRECIATED.
I can not help you about the knocking, because my engine is runnng fine, maybe you can check fuel, and try to fill at different place. I have modified my original prop and now it is about 19x20. Now I can reach about 3950 rpms, and I am going about 16 knots at 3400 rpms loaded with fuel, water and gear. Before I also have a feel that boat is over propped. Also, I have mounted QL trim tabs and they work like dream. I get about 0.5 kn at cruising and also tehy put bow down, which makes ride through waves more pleasant.