Newbie Needs Advice

[SeaForTwo]

I recently had two DF300's installed on my 27 foot aluminum cruiser, with Mercury performance props installed. I have never ran a boat with this much "go". Here's my issues/questions. When accelerating from standstill both props lose bite and the engines rev quite high. The motors take turns getting ""bite" and eventually everything settles down. This is issue number 1. Issue number two is that at WOT the best I can get is around 5400 rpm. Manual says I'm looking for between 5700 and 6300. I've spoken with the shop that installed the motors and have received the following advice: When starting, trim motors up to 1 or two bars. As the boat accelerates trim motors up further such that when the boat is on plane and at WOT the motors are trimmed to 3 or 4 bars. Haven't tried this yet. Does this advice make sense? Does anyone else have some advice. Thanks

[Harper2]

It could make sense (and you should hope that it's really that simple). But the only way to know for sure if it's the answer to your problem, is to take the boat out and try it, using your dealer's suggestions. Different boats have different handling characteristics and the same boat will handle differently with different power setups. Eventually you should be able to figure out how best to use the engine trim on that particular boat, but also you might have to adjust such things as the mounting height, as well as trying different props in order to find the right ones.

Now....there are more considerations that need be addressed with multiple motors. In addition to those things that I've already mentioned, which are applicable both to single and multi-engine layouts, with two motors you need to adjust things such as mounting distance between the motors, toe-in or toe-out, counter-rotating props (hopefully yours are counter-rotating) ... until properly addressed, all these items can cause problems with handling and props ventilation (which you are definitely encountering, according to your description of "taking turns getting bite"). And there are probably other things that I haven't thought about.

So you and your dealer have some work to do in setting up this boat properly. It will likely take a lot of trial and error (and time). I can only hope that your dealer cares enough to stay with you on the problem until you are satisfied that it is right.

[SeaForTwo]

Thanks Mike. It's as I feared.