Motor Height and Trim question

[mpilot]

I've been running the boat for a few weeks and I'm happy overall with the boat, but I have a couple of questions. It's a Cypress Cay 230 with the PP+ package with the full third toon and a Mercury 150 Four Stroke. Right now I'm only hitting 5300 RPM's wide open trimmed all the way up. It appears to be in the highest mounting position, but when I am running I can never "over trim" where you start to cavitate. I know you don't want to cavitate but on my old boat, and a few other tritoons, it seemed that if you trimmed it up until it just started to lose grip then bumped it down until it caught was the optimum trim for straight line speed. I do have double bimini tops but I'm only seeing mid 30's with them open and all performance bulletins show in the low 40's. I'm going to close them and see what that does, but I'm still not getting all of the RPM's I can out of the engine.

Unfortunately I have a 10 week old so the wife hasn't been able to get on the boat and drive while I look to see what exactly is going on with the height of the motor but I'm going to try and get a friend to come over this week and do a test run, or hopefully the dealer will send someone to check it out. I did notice today that I'm getting spray all over the motor when running wide open trimmed up so I think the motor is still too low even on the top notch. I'm not sure what the dealer/manufacturer can do if this is the case.

First, I'm going to make sure it's propped with the same prop from the tests. Next, I'm going to run it with no bimini tops open and see what it does. Any other thoughts/suggestions?

Edit to add:
I just looked at the performance bulletin and the mounting hole is listed as the 2 hole. I'm not seeing the normal issues of the motor being mounted too high, but could that cause water spray and loss of speed somehow without cavitation?...Is it possible something is causing the boat to sit lower in the water? (please no water in the toons of a brand new boat) It was just me, a small cooler, and 3/4 tank of gas (30 gallons) on board today.

[Bamaman]

Every boat brand and model and engine combination is different. My F150 Yamaha is setup 3/4" off the transom--one notch--and it's running with very, very low slip ratios (all things relative.) My boat will ventilate slightly upon hard acceleration, but when I trim the motor down a little it'll corner just fine without any venting. That's just like I like it. I'm running 40 mph @ 6000 rpm's with a Yamaha Reliance 15 pitch stainless prop.

But if I look at the anticavitation plate on my motor, I cannot see it when cruising or running fast. A visual on the motor underway is no indication of how efficient your're running.

It sounds as if you may need to drop your engine, and you might need a different pitch prop. I still find it strange that different props can perform so much differently in spite of being the same pitch, etc. Some props actually lift the rear end more than others, and that's when you get ventilation quicker. Also, some props lift the front end better. It's all an inexact science--one of balance.

Don't expect to be running in the 40's with 150 hp. You for sure should be over 35 mph, however.

[teecro]

Will say that while OK your top wide open RPM sounds a tad too low in that Mercury states 5,000 to 5,800 in their spec sheets for that motor... This would indicate that you may be spinning too much pitch. I'd suggest trying props with less pitch by 2 or even 3 inches, but I would also suggest that you double check the transom to motor mounting height and see if your able to raise the motor any as while a good thing that you can't affect or cause a blow out by over trimming you should be able too... Another question would be what size pontoon diameter and are you running a short or long shaft? That can be found in the engine model number plate. Also dual open Bimini tops will cost you speed as well as RPM even two Bimini tops in Radar will cost you some too...

[mpilot]

I'm running 25 inch toons and the third toon is set an inch lower. I'm going to have to get in the water to check the prop matches the one from the performsnce bulletins to start. I sent an email to the dealer this morning so hopefully they'll send someone out for a test drive since they neglected to do one when they delivered the new boat a few weeks ago. There already is a list of things they are working with the factory to fix so we'll just add this issue to that list I guess. Id like to see the full 5800 rpms like the two boats mercury tested with identical hull and engine setups

Also, teecro the motor is in the top mounting hole. I went and checked this morning but Iif I trim the motor all the way up it only registers as 3/4 on the gauge. I'm going to have them double check if the actual trim limit or just what is being sent to the gauge is out of adjustment.

[teecro]

I'm running 25 inch toons and the third toon is set an inch lower. I'm going to have to get in the water to check the prop matches the one from the performsnce bulletins to start. I sent an email to the dealer this morning so hopefully they'll send someone out for a test drive since they neglected to do one when they delivered the new boat a few weeks ago. There already is a list of things they are working with the factory to fix so we'll just add this issue to that list I guess. Id like to see the full 5800 rpms like the two boats mercury tested with identical hull and engine setups

Also, teecro the motor is in the top mounting hole. I went and checked this morning but Iif I trim the motor all the way up it only registers as 3/4 on the gauge. I'm going to have them double check if the actual trim limit or just what is being sent to the gauge is out of adjustment.

Lets not confuse each other (me) here.... Is you motor mounted to the transom so that it is as HIGH out of the water as it can go or as low in the water as it can go? I think you just described as low as it can go. If so try lifting the motor 2 holes or 3 holes and try another test run to see if your RPM improves....

Also in case you have not noticed Mercury motors will only allow just "so" much trim once RPM is over 2,000 and no matter how you try it self lowers or refuses to trim higher than a specific point....

[mpilot]

I'm running 25 inch toons and the third toon is set an inch lower. I'm going to have to get in the water to check the prop matches the one from the performsnce bulletins to start. I sent an email to the dealer this morning so hopefully they'll send someone out for a test drive since they neglected to do one when they delivered the new boat a few weeks ago. There already is a list of things they are working with the factory to fix so we'll just add this issue to that list I guess. Id like to see the full 5800 rpms like the two boats mercury tested with identical hull and engine setups

Also, teecro the motor is in the top mounting hole. I went and checked this morning but Iif I trim the motor all the way up it only registers as 3/4 on the gauge. I'm going to have them double check if the actual trim limit or just what is being sent to the gauge is out of adjustment.

Lets not confuse each other (me) here.... Is you motor mounted to the transom so that it is as HIGH out of the water as it can go or as low in the water as it can go? I think you just described as low as it can go. If so try lifting the motor 2 holes or 3 holes and try another test run to see if your RPM improves....

Also in case you have not noticed Mercury motors will only allow just "so" much trim once RPM is over 2,000 and no matter how you try it self lowers or refuses to trim higher than a specific point....

Sorry about being confusing. The motor is as high as it will go right now in the bottom hole of the five. Meant to say highest mounting position. I am aware of that feature of the trim but from what I'm reading there may be a little adjustment to that, but I'm not 100% sure.

[teecro]

... Sorry about being confusing. The motor is as high as it will go right now in the bottom hole of the four. Meant to say highest mounting position. I am aware of that feature of the trim but from what I'm reading there may be a little adjustment to that, but I'm not 100% sure.

You know I would not be surprised to find out that you have a 25" long shaft mounted on that boat. As with 25" toons and the center toon being even 1" lower still it would "sort of" make sense to go that route and then being forced to mount the motor high to soak up the extra length... Find out what blade your running... Most likely a Mercury Black Max; you should find the number cast into the hub between the root of the blades as well as right in the back when looking at the prop nut...

[mpilot]

... Sorry about being confusing. The motor is as high as it will go right now in the bottom hole of the four. Meant to say highest mounting position. I am aware of that feature of the trim but from what I'm reading there may be a little adjustment to that, but I'm not 100% sure.

You know I would not be surprised to find out that you have a 25" long shaft mounted on that boat. As with 25" toons and the center toon being even 1" lower still it would "sort of" make sense to go that route and then being forced to mount the motor high to soak up the extra length... Find out what blade your running... Most likely a Mercury Black Max; you should find the number cast into the hub between the root of the blades as well as right in the back when looking at the prop nut...

I looked on the Cypress Cay website and they do indeed run the 25" long shaft which is what I have. The prop in the tests was an Enertia 15.3 inch x 14 pitch prop and I have an Enertia 15x15. I'm going to ask them to get me the other prop and swap them as a start.

I'm assuming that even though I will lose an inch of pitch I will actually gain some of the speed because I will be turning (hopefully) the other 500 RPM I'm missing? Thanks!

[teecro]

... I'm assuming that even though I will lose an inch of pitch I will actually gain some of the speed because I will be turning (hopefully) the other 500 RPM I'm missing? Thanks!

An inch of pitch generally equals 200 RPM...

[mpilot]

An inch of pitch generally equals 200 RPM...

What about 0.3 more inches diameter?

[teecro]

What about 0.3 more inches diameter?

No clue... Not likely anything tangible...

[mpilot]

What about 0.3 more inches diameter?

No clue... Not likely anything tangible...

I figured as much. I talked to the dealer today and they are contacting Cypress Cay to see which prop is the one that should have been rigged on it. I don't know why there would be multiple tests over multiple years with the identical hull and engine using the 15.3x14 prop and then mine has the 15x15 on it. Either way he agreed we need to look at dropping the pitch and looking at the height. I know it's a heavy boat compared to some others but I though for sure I would at least be able to touch 40 with it. I mentioned to him also the tests all ran on mount hole 2 and mine is mounted as high as it can go. He also is going to confirm with them the proper mounting hole. The speed pickup and all is in the foot of the motor and there is nothing external mounted on the toons yet so the motor, engine pod, or something else is causing the excess water spraying out the back of the boat.

[Bamaman]

You're thinking right about what to do. The 14 pitch is probably the right way to go. The Enertia prop is a great one for pontoons and it's especially nice they're available in 1 pitch increments--to completely fine tune the prop to your needs.

My next door neighbor's Harris tritoon with a Verado 150 is running an Enertia 14 pitch.

And don't worry about the water spray coming out of the back end. It's something you really cannot do anything about. Like I said, my prop slip is very low, and I cannot see the anticavitation plate on my lower unit for all the spray.