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Mercruiser Alpha One Sterndrive Trim Adjustment

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pbuzzy

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I just bought a Permatrim for my Mercruiser Alpha One Sterndrive. I am about to fit it and realised that once fitted, if I trim my drive all the way up (or out I guess), then the Permatrim will hit the swim platform I have fitted to the back of my Four Winns H180. What I am worried about it, is that when I am on the water and trim the motor all the way up, and forget, then I reckon it will either crack the swim platform or damage the leg/permatrim. I am more worried about the swim platform as to fix it or replace it would cost a lot. My question is, on the leg there is something called a Trim Limit. Can this be 'adjusted' to stop the leg before it hits the swim platform ? If so, how do I adjust it ? I only want to adjust the trim out, and not the trim in, as all the way in is perfect now. Is this possible ? I have attached photos.

In the photo's, I have only trimmed the leg up about 80%, but as you can see, its about to hit the platform. It would have another 4 inches to go easily.

Its a Mercruiser Alpha One Sterndrive on a Four Winns H180 2011 model.
 

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The trim limit only works on the up circuit, maybe its not connected, look to see if there is a black twin cable with two male bullet connectors on the inside of the transom. They should be plugged into the blue /white cable going to the trim pump. When you trim up with the button on the throttle it should cut out when the cylinders are extended around 21 ", then you use a second button to trim up to trailer position. The tilt switch is to prevent the drive trimming out of beyond the support guides while driving.
The trim limit is not intended for the angle your drive is at in the pics, the best solution is look at or fit a trim gauge.
 
The trim limit switch is to control TRIM, NOT Trailer.

Trim = amount outdrive can be raised while under power to raise boat out of water to achive maximum performance. The trim switch is used to set this hieght and can only be adjusted after water testing. Typical rule of thumb setting is count (one onethousand, two onethousand, three onthousand) and the switch should stop the drive from moving any higher. While water testing if the boat cavitates then the switch needs adjustment.

Trailer = the second botton that will raise the drive all the way up for trailering. (bypasses trim limit switch) NO ADJUSTMENT for any stopping it at a given hieght.

If the hieght with the new fin on is too low to trailer then remove it.

Mercruiser does NOT reccomend installing these on the outdrives...........Affect steering adversly............

If your boat is having difficulty getting on plane then it is a power vs wieght issue and the boat manufacturer is to blame for under powering the boat from the get go........
 
pbuzzy said:
I just bought a Permatrim for my Mercruiser Alpha One Sterndrive. I am about to fit it and realised that once fitted, if I trim my drive all the way up (or out I guess), then the Permatrim will hit the swim platform I have fitted to the back of my Four Winns H180. What I am worried about it, is that when I am on the water and trim the motor all the way up, and forget, then I reckon it will either crack the swim platform or damage the leg/permatrim. I am more worried about the swim platform as to fix it or replace it would cost a lot. My question is, on the leg there is something called a Trim Limit. Can this be 'adjusted' to stop the leg before it hits the swim platform ? If so, how do I adjust it ? I only want to adjust the trim out, and not the trim in, as all the way in is perfect now. Is this possible ? I have attached photos.

In the photo's, I have only trimmed the leg up about 80%, but as you can see, its about to hit the platform. It would have another 4 inches to go easily.

Its a Mercruiser Alpha One Sterndrive on a Four Winns H180 2011 model.
Click to expand...

Ayuh,.... You shouldn't have the drive That high, when In the water, Anyways,....

If ya start the motor, with the trim That high, yer bindin' up the u-joints, 'n will ruin 'em,....
 
kghost said:
The trim limit switch is to control TRIM, NOT Trailer.

Trim = amount outdrive can be raised while under power to raise boat out of water to achive maximum performance. The trim switch is used to set this hieght and can only be adjusted after water testing. Typical rule of thumb setting is count (one onethousand, two onethousand, three onthousand) and the switch should stop the drive from moving any higher. While water testing if the boat cavitates then the switch needs adjustment.


Sorry but thats not correct, the manual give a specific ram extension length for Alpha and Bravo drives and this is when the limit switch stops the trim motor.
Its nothing to do with water testing as every boat I've driven both Merc and Volvo will cavitate before you hit the limit, the reason you have so much travel is to cope with varying loads/speeds and sea conditions, you need lots more up trim running with the waves than normal.
Even the Nortech I maintain will cavitate before reaching the limit and we are talking 120kts speed here!
Click to expand...
 
Draco24 said:
kghost said:
The trim limit switch is to control TRIM, NOT Trailer.

Trim = amount outdrive can be raised while under power to raise boat out of water to achive maximum performance. The trim switch is used to set this hieght and can only be adjusted after water testing. Typical rule of thumb setting is count (one onethousand, two onethousand, three onthousand) and the switch should stop the drive from moving any higher. While water testing if the boat cavitates then the switch needs adjustment.

Sorry but thats not correct, the manual give a specific ram extension length for Alpha and Bravo drives and this is when the limit switch stops the trim motor.
Its nothing to do with water testing as every boat I've driven both Merc and Volvo will cavitate before you hit the limit, the reason you have so much travel is to cope with varying loads/speeds and sea conditions, you need lots more up trim running with the waves than normal.
Even the Nortech I maintain will cavitate before reaching the limit and we are talking 120kts speed here!
Click to expand...

Opinions are like A$$ holes everyone has one.

And no I am not wrong!!!!

There is NO defined dimension for trim..PERIOD!

Every boat and hull is different and so is the trim stop or trim out position. What is in the manual if it is even there is for a refernce only and will vary based on the boat design and other factors including the X demension...........

THE ONLY WAY TO SET UP PROPERLY IS BY WATER TESTING.

IF MORE TRAVEL IS NEEDED FOR VARYING CONDITIONS THEN USE THE TRAILER SWITCH.

And yes ONE of the reasons for trim is to achieve maximum performance (top speed).
Click to expand...
 
Being a 2011, this should have the two position "up" rocker switch on the control handle. By pushing the rocker switch "up" with little pressure, activates the trim circuit, where the drive will only raise to the upper limit as per the setting of the limit control switch on the out drive. Under normal (on the water) operation you shouldn't hit the swim platform with the trim circuit energized ....you'll get cavitation long before the swim platform is contacted. Pressing the switch "up" a little harder, past the detent, activates the trailer circuit where the drive will raise all the way up...this is where you may encounter problems and hit the platform.
 
izdbye said:
Being a 2011, this should have the two position "up" rocker switch on the control handle. By pushing the rocker switch "up" with little pressure, activates the trim circuit, where the drive will only raise to the upper limit as per the setting of the limit control switch on the out drive. Under normal (on the water) operation you shouldn't hit the swim platform with the trim circuit energized ....you'll get cavitation long before the swim platform is contacted. Pressing the switch "up" a little harder, past the detent, activates the trailer circuit where the drive will raise all the way up...this is where you may encounter problems and hit the platform.
Click to expand...

Good input. I have not seen or used this type of control handle on the newer boats.
Most i work with are no newer than early 2000's...
 
kghost said:
Draco24 said:
Opinions are like A$$ holes everyone has one.

And no I am not wrong!!!!

There is NO defined dimension for trim..PERIOD!

Every boat and hull is different and so is the trim stop or trim out position. What is in the manual if it is even there is for a refernce only and will vary based on the boat design and other factors including the X demension...........

THE ONLY WAY TO SET UP PROPERLY IS BY WATER TESTING.

IF MORE TRAVEL IS NEEDED FOR VARYING CONDITIONS THEN USE THE TRAILER SWITCH.

And yes ONE of the reasons for trim is to achieve maximum performance (top speed).
Click to expand...

Wow! someone got out the wrong side of bed today .
I suggest you study the manual a bit more and then go look at the back of a boat, if you open your eyes and look carefully you will see that the drive slides out between two wear plates which support it laterally. The limit switch is to prevent you trimmng the drive out past these while under way as then if you apply some steering the whole drive is only held laterally by the pivot pins.
Its very arrogant to suggest that Mercruisers trim limit dimension is for reference only, if you do it your way and use the trailer button to get more trim you have no way of knowing if you are out beyond the support guides, not a proffesional way to set up a boat.
If you can't accept a litte constructive criticism without getting obnoxious , perhaps you should try another forum.
Click to expand...
 
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Draco24 said:
kghost said:
Wow! someone got out the wrong side of bed today .
I suggest you study the manual a bit more and then go look at the back of a boat, if you open your eyes and look carefully you will see that the drive slides out between two wear plates which support it laterally. The limit switch is to prevent you trimmng the drive out past these while under way as then if you apply some steering the whole drive is only held laterally by the pivot pins.
Its very arrogant to suggest that Mercruisers trim limit dimension is for reference only, if you do it your way and use the trailer button to get more trim you have no way of knowing if you are out beyond the support guides, not a proffesional way to set up a boat.
If you can't accept a litte constructive criticism without getting obnoxious , perhaps you should try another forum.
Click to expand...

The wear plates are as you say, BUT they also as you say are for the normal trim amount (not trailer amount).
It is clearly not reccommended to run a boat at any higher than idle speed when using the trailer position. too much strain on the ujoints.

I have read in my opinion a shat load more boat manuals then I suspect you every will.

And No I did not wake up on the wrong side of any bed............

All I can say is I have set up many many NEW boats and old ones for that matter over many years........

I will repeat myself so read carefully.
The predetermined length for the trim/trim switch is only a reference in the manual. In the real world one adjusts the trim limit switch so no ventialtion/cavition occurrs. Doing this will not go past the wear pads or cause any issues.
If the boat ventilates/cavitates then the switch needs to be adjusted so it does not. PERIOD.
This is also an adjustment that needs to be lake tested to be sure and NOT in rough seas but in relatively calm water.



If the maximum trim lentgh could be predetermined for every boat that easily there would be no need for a rotary switch and they would simply include a linear switch on the trim ram so that Maximum lentgh would never be greater.
Click to expand...
 
Suggest you read page 14A 16,17 in the Mercruiser drive manual then tell me you didn't learn something. If you only set them up on a lake then what happens when you get some real following waves, I'm guessing you will have nowhere near enough up trim. Also you are out on you own sea testing a lightly loaded boat if its new, and you have set the limit to the max before cavitation, then the sucker who's bought it fills it with fuel, family and junk and its nowhere near the right adjustment now.
Seeing as I live in a land where 1 in 5 has a boat and we deliver boats all year round I doubt very much you have set up more new boats than I have, but I can't be arsed to get into a pissing contest. However if it comes to believing a multimillion dollar corporation who builds the damn Things, or you, I know where my money is going. I can honestly tell you there isn't one dealer in the whole of Norway that does what you do, can so many be wrong? Especially as its never ever been mentioned on the dozens of factory courses I've done With Mercruiser and Volvo Penta.
I hope you have a nice weekend, I sure am .
Have a nice weekend
 
Ok

As you said, I doubt you have seen as many as I,
If you reread the manual, there are two ways to adjust, Static (measurement as in the manual) on land and in the water while water testing.

So how/why would one measure anything while in the water? Simply loosen screws and rotate the switch to adjust.

Thus it is based on boat load, design, water useage (sea or inland lake).....way to many varyables to say ONE dimension is the only dimension to be used.

Bottom line in my opinion,

1. If you set it up to a static measurement and it ventilates when under normal use then it is set wrong and needs to be adjusted so no cavitation occurs.

2. If due to many varialbles the static setting is to short you will never reach max performance under wide open throttle without using the trailer function.

So if my opinion is considerd true then a static adjustment on land is merley that. A static adjustment. The final and appropriate adjustment must be made for each individual boat during a water test. If not, it is merely a estimate regardless of a specified dimension in the manual.
If you were ask a merc rep/instructor I am sure he would parrallel my opinion.......As I have........I did not come up with this from my back yard.......
 
izdbye said:
Being a 2011, this should have the two position "up" rocker switch on the control handle. By pushing the rocker switch "up" with little pressure, activates the trim circuit, where the drive will only raise to the upper limit as per the setting of the limit control switch on the out drive. Under normal (on the water) operation you shouldn't hit the swim platform with the trim circuit energized ....you'll get cavitation long before the swim platform is contacted. Pressing the switch "up" a little harder, past the detent, activates the trailer circuit where the drive will raise all the way up...this is where you may encounter problems and hit the platform.
Click to expand...

Yes this is exactly right. It has the two position switch. If I depress it lightly, then it only travels about 1/4 of the way out and stops, which is what it is supposed to do. If I depress harder, then it travels all the way out (for trailering). It is at this stage that I am concerned. If I am putting the boat on the trailer and forget to stop the trim before it gets to the end of its stops, then I will hit the swim platform and probably damage it. This is where I want to limit the distance it travels. This is what I hoping to adjust on the trim limit on the port side of the stern drive.
 
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Docksidemarineservices said:
Why did you install this to begin with? It is not needed.
Click to expand...

Can I ask everyone's opinion of this? The reason why I fitted it is because when I have a bit of weight in the boat (day 4 adults and 4 kids) and I have a tube behind, the boat really struggles to plane, if at all.. I even distribute the weight evenly throughout the boat (like all kids in the bow, and even adults) and it still struggles to plane. I sit in the water at 45 degrees and the boat will not accelerate at all. It's almost like it has absolutely no power. I was hoping the permatrim would help me plane quicker, and the guys at permatrim (and other boat places) have all said to start with the permatrim and that should solve the problem.

I also notice that that kghost above says 'Mercruiser does NOT reccomend installing these on the outdrives...........Affect steering adversly............' Is this true? Does anyone know of someone who has one of these fitted to a mercruiser sterndrive and they have regretted it because it has affected the steering? Permatrim claim this is not the case.

Any thoughts or or experience is appreciated.
 
Yeah I thought so chris. I am wondering why some boat places I have phoned have claimed this can be done, but I suspected it's not the case due to what I read on other forums.
 
It would be easier for you to under prop your boat for tubing. Take the Trim fin off. They stress the drive and affect steering. No Fin, Lower your prop pitch for tubing and no worries about damage to your platform.
 
The other alternative is to install adjustable trim tabs, many large boats come with them installed and they are hydraulic. Some are spring loaded.
Although the hydraulic ones typically assist in boat listing, on smaller boats they aid in planning faster. May or may not be an option.

Over all Chris is correct, a smaller pitched prop may be the solution.

there are torque shift (auto and adjustable pitch) props available. They are adjustable and they will act like
example: initially they may be a 15 pitch but at a adjusted setting (usually equates to some rpms like 3200 -3800) and they will mechanically shift to a 19 pitch .

This gives you a hole shot but normal cruising rpms and speed.

Many people install the fins for your reason, very common. BUT as I said not recommended......can reek havoc at high speed turning and possible loss of steering control especially for a smaller weaker driver/operator
 
Docksidemarineservices said:
It would be easier for you to under prop your boat for tubing. Take the Trim fin off. They stress the drive and affect steering. No Fin, Lower your prop pitch for tubing and no worries about damage to your platform.
Click to expand...

Exactly^^^^^^^. Can we change the subject for a bit? What pitch prop do you have installed? What is your max RPMs at wide open throttle?
 
An 18 footer with 4 adults , 4 children, the cooler and powered by a 140hp motor and you wonder why you have trouble planning.
And if by chance its a V6,yo have a serious engine issue.
 
7 persons @ 1500 lbs.do the math
Warranty: 8 years
Hull Shape: Modified Vee

Dimensions
LOA: 17 ft 4 in
Beam: 7 ft 6 in
Minimum Draft: 1 ft 5 in
Maximum Draft: 2 ft 10 in
Bridge Clearance: 3 ft 8 in
Deadrise: 21 ° at Transom
Dry Weight: 2400 lbs
Max Load Capacity: 1150 lbs

Engines
Engine 1:
Engine Brand: MerCruiser
Year Built: 2011
Engine Model: 3.0 MPIC Alpha
Engine Type: Inboard
Engine/Fuel Type: Gas/Petrol
Drive Type: Stern drive
Engine(s) Total Power: 135 HP

Tanks
Fuel Tanks: (24 Gallons)

Accommodations
Seating Capacity: 7
 
Merc sells spacers that go in the trim cylinders to shorten stroke length to prevent a drive from hitting the swim platform. Or you can just use a piece of Aluminum tubing over the rod inside the cylinder on the rod side of the piston.
 
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