Re: More HP / Changing Pitch
This is a cruiser QC, not a speed boat, what the heck does 1 mph faster matter? I am basing my recommendation on a few factors:
1) Propping to the high end of the WOT RPM makes the engine work easier across the whole rpm range
2) Easier working engine equals less fuel burn.
3) The boat bottom is as clean as it's going to get and the load sounds light. Those things will only change and cause more drag
4) Vortec Chevy engine are very suseptible to "tulipped" valves due to lugging the engine.
5) The motors are producing their peak power now, and as the humidity and heat levels rise this summer, they are only going to produce less power.
But as I said, do what you want. You seem enamored with turning the 25s, so do it. If/when you have to change to the 23s, please update us.
I can't say for sure, but I believe what QC was referring to, was not the maximum speed at WOT, but rather the maximum cruising speed. 3200 RPM is where the engines will be run most of the time, and will yield the best fuel economy. Once the secondary?s start opening up, fuel economy will suffer. Gas is approaching $5 per gallon here, and expected to go higher. I want the best fuel economy with these engines I can get.
As far as being "enamored" is concerned... that's simply not the case.... and you presume too much. I?m certainly no prop expert, but I can read. If the WOT RPMs were not within the Mercury published specifications, I would change the props again in a heartbeat. Fact is, the RPM is just about right in the middle of that range. If these engines were designed and built to run exactly at 5000 RPM at WOT as you suggest, the engine specifications would reflect that.
No disrespect, but I am going to go with Mercury's recommendations over yours, or anyone else?s for that matter. They are providing the warranty on my new engines.
Thanks to all for your comments.
