2012 Mercury Optimax Pro XS 150 prop/jack plate

[Levitts4]

Hello all, I may be in the wrong place and correct me if so, but I just purchased a 2012 Stratos 285xl with the 150 pro xs. I purchased from c&o marine in TN. They have nowhere to test drive the boat. I was able to take it out this past Sunday for the first time. I had them install a manual 6” plate and they set it up I assume with a standardized height. The boat was propped at some point with previous owners with a Mercury trophy plus 21p 4 blade prop. My first thoughts while getting on plane was that it was mildly sluggish and bogged quite a bit it seemed. So my first question is, is this related the plate height and prop not jiving and needs to be adjusted? Secondly, the engine idles around ~900 rpm in neutral so to me the rpm gauge seems correct. My question is after getting on plane the rpm’s almost seemed to jump straight wot completely pegged on the gauge at 7k. Motor doesn’t seem like it’s actually running that hard to me and i was only seeing like 52.8mph gps.i was afraid to trim the motor up anymore due to the rpm’s. I noticed too that the water pressure was around 14-16ps while I was running. I spoke with c&o and the only thing so far they’ve said is that there is something wrong with the rpm gauge. As in, it could be bad (which I don’t think it is due to the above mentioned rpm at idle) or something is off on the back of it. It is not an easy or short drive for me to take it back to them. Hopefully they can send me somewhere else at their cost that’s more local. Sorry for long post but I know you guys know what you’re talking about. Thanks in advance for any assistance.

[SilverFox579]

You are in the correct forum for your 150 ProXS.

By your description you have an analog tach, many of which are notoriously innacurate. I highly recommend a Smartcraft gauge of some kind, it will display accurate information provided by the engine computer (PCM).

For Smartcraft info - SMARTCRAFT Options
Should you wish to order one, great assistance and super help - If you want to order or price Mercury Engine Parts or Accessories

Someone else more familiar with your boat/engine combo will be along to help with your setup questions.

[JOE54]

tach is likely set wrong for this engine thus reading much higher than it typically should , you would be getting overspeed warnings for sure , might ask in the STRATOS forum for suggestions on propping or PVS adjustments

[EuropeanAM]

Most of the 18-19' boats with 150's actually performed better WITHOUT a jackplate.

[Levitts4]

Thanks for the suggestions thus far. I traded my 2000 javelin renegade 18 in on this boat. It had a 2000 johnson 150 with a 6” plate and it was dialed. Someone that had it previous to me had it dialed in. She jumped out the hole and would run 62-63 (sketchily I may add) by myself. So I think it could be dialed in with the plate and prop combo. Just not sure where to go with that. I need to measure the current set up and post in the Stratos forum.

[EuropeanAM]

Check your propshaft to pad measurement (Currently).