Need to raise motor

B

breausaw

New member
Taken directly from the Permatrim USA.
http://www.permatrims.com/category_s/12.htm

To verify the outboard installation height, trim your engine all the way down and take a straight edge and place it at the bottom side of the AV plate. Carry that straight edge forward and see that the straight edge is now level with the hull bottom.

From everything I have read having the engine at the right height is imperative for the Permatrim to function properly.

My engine needs to be raised up a notch to achieve proper high according to this statement taken directly form the Permatrim site, so how hard is this? I looked aft while the wife had the helm to see my Permatrim under water.
I know some brats have done this, and it can’t be that hard from looking at the bolt-on set up. The bottom bolts have a slot for adjustment and to top bolts have 4 adjustment holes. If I leave the bottom bolts a little loss and pull the top bolts I should be able to jack the motor up, run the top bolts back in and tighten everything up.
Realizing I have to use a lot of 5200 or 4200 in the process along with loosing up the motor for movement.

I know is looks easy but can’t be as hard doing a V8 long block swap, which I have.
.
If someone has raised their motor and has direct experience doing the job any helpful tips would be great!

Thanks...
 
Never raised a motor before, but I figure I can put in my $.02 worth anyway!

I would venture a guess that it would be ok to do what you propose, but I would also add a thin strip of material (starboard, perhaps?) along the top of the transom to fill in the gap that you raise the outboard. I know there is a lot of torque and stresses where outboards mount, so I would think "shimming" the top of the transom could only help keep the outboard from slipping down again.

Glad to see another Alaskan on the boards!
 
I did it with my Yami 80's, 2 holes up. I simply put a wood block between the skeg and my hydraulic floor jack and lifted VERY CAREFULLY about 1/4" at a time while checking for any binding, etc. I did the same thing, removed the top mounting bolts then loosened the bottom bolts to allow it to slide. Hard part was resealing the bolt holes and reinserting the upper bolts while ensuring a good seal.

Good luck!
 
yeah this is not hard, and doesnt take too long either, ive installed a few motors, just put one on my boat, the only thing i can say is that i seemed to have notices on a few boats, when the motor is directly on the transom cap, the the vibration can eventually crack the transom top, letting water in and rotting out the transom, i think its fine if you have a small gap between your motor and the transom cap, no shim necissary....
 
Jay,

I would be interested in hearing the results in performance if you do change engine height. To be truthful, I ignored that when I installed the Permatrim on Constant Craving. My speeds and economy seems to be much the same, and I am impressed with the degree of control that I now have over the fore and aft attitude of the boat.

The only thing that I would remotely describe as as undesirable is a tendency to torque turn with lots of throttle/speed and the engine trimmed all the way down. It goes away as soon as the engine is trimmed up.

Steve
 
I probably need to move my motor up two holes, but the slottled lower "hole" will only allow one. We have considered using a tractor front loader with a chain to pull up the engine--seems easier than a jack, and safer.

I used to think that the transom support was necessary, but it is not. Almost all boats with the larger engines have the weight on the 4 bolts and no weight on the transom cap.

One of my concerns is that under certain condtions I will get cavitation with the current setup-- (the plate is about 3/4" below the transom)---and fear that the cavitation might be worse if we were to raise the motor too much.
 
I read somewhere, i'll try and find it, that a good way to do this is to build up under the skeg with, for example, a concrete block, and then soft wood , like a 4x, with a skeg notch cut in it, then after bottom bolts are loosened (slightly) and top are removed, slowly jack up the front of the trailer with your hydraulic jack. In fact with the huge leverage, you may be able to lift it easily with simply using the trailer tongue jack. you can make the minor adjustments to seat the skeg on the wood with the trailer jack.

chris
 
I recently acquired Permatrims. I think they are a significant help in adjusting bow attitude, lateral level (I have twin engines), and in maintaining plane at lower speeds. They do not seem to have reduced top speed or mileage in any detectable way.

I, too, was quite concerned about engine depth, having read what was available on the subject. To begin with, in my opinion the AV plate measurement is pretty arbitrary, especially with twin engines and any dead rise at all. I mean what exactly is "level with the hull bottom?" Figuring this out has got to be as much art as science. My boat has 5 degrees of deadrise at the transom, so the Permatrims on the twins are, of course, not centered on the lowest point. My best eyeball estimate is that the center of the Permatrims (which are horizontal) hits just at or minutely below the corresponding points on the transom lower edge (which is 5 degrees off horizontal). Of course, the Permatrims are still slightly above the lowest point (center) of the hull bottom. This measurement will, of course, be a little more straightforward with a single engine or a boat with even less deadrise.

I talked on the phone at some length with a guy (Stan?) at the Permatrim dealer about this engine depth issue. He said he was sure my engines as I described them would be just fine. He said not to take any offense, but with "slower boats" the depth issue is much less critical. (I took the comment as a compliment.) Apparently it's at speeds above about 40 mph that height adjustment can become really significant.

Don't have any independent corroboration for what I was told other than the excellent performance I've experienced with my Permatrims.
 
I read somewhere, i'll try and find it, that a good way to do this is to build up under the skeg with, for example, a concrete block, and then soft wood , like a 4x, with a skeg notch cut in it, then after bottom bolts are loosened (slightly) and top are removed, slowly jack up the front of the trailer with your hydraulic jack. In fact with the huge leverage, you may be able to lift it easily with simply using the trailer tongue jack. you can make the minor adjustments to seat the skeg on the wood with the trailer jack.

chris
Click to expand...

I have done just what CEMIII indicated in his quote above. Actually once the motor is loosely attached by the bottom bolts (or just floated on the skeg) and supported on the skeg, the tongue jack easily provided minute adjustment to align the new upper hole placement. We used two persons to do the job, one to stabilize the motor to avoid a bad situation and the second to operate the tongue jack. The whole process to raise two holes took about 30 minutes. The subject boat was a Boston Whaler and raising the motor to bring the anti cavitation plate even with the bottom raised the top speed and increased fuel mileage.
 
Brian and Kevin
My 90 Honda doesn’t rest on the transom cap, all weight is on the 4 bolts.

Steve,
We are thinking exactly alike; this is the approach I had in mind.

Chris,
Great idea

Bill,
Waiting to here back from Permatrim regarding this issue. I was going to talk with them before doing the lift, so if they think its not necessary guess I’ll bag it. What ever they have to say I’ll share it with the group.

Thanks for all the feedback..
 
Talked with Andy Jr. at shipyard Island Marina, where I bought the Permatrim.
He said raising my motor to the point where the CP is even with the bottom would be ok; a notch above would be ok if running a stainless prop. Said the stainless has a better bight in shallow water where aluminum would probable cavatate.
Said raising the motor would defiantly produce better results but couldn’t suggest how much improvement I would see.
He also suggested Chris’s idea of blocking the skeg and raising the trailer to lift the motor, said he’s done this at the ramp.
I plan on raising the motor this weekend before our 3 day excursion next week, let you know the results.
 
Jay,

I get geometrically challenged at times so am having a hard time interpreting what Permatrim is saying. If I trim the motor down until the motor's cavitation plate is parallel with the bottom of the boat (using a 4' carpenter's level), the cavitation plate is about 3/4 inch above the plane of the bottom. As I continue to trim the motor down the leading edge of the cavitation plate approaches the top of the level and then ends up almost 1" below the top of the level when fully down. I almost never run with the motor fully down and with a Permatrim, that full down position would definitely drive the bow down into the water.

So the question is, with your motor trimmed to where the cavitation plate is parallel to the bottom of the boat, where is the cavitation plate in relation to the bottom? On the same plane, above the plane of the bottom, or below the plane of the bottom.

If I raised my motor any further, as the cavitation plate approaches a plane parallel to the bottom of the boat it would be in excess of 1 inch above the plane of the bottom. Besides that, I am not sure I am raise the motor any further as I am running out of transom. The top bolts are about 1.5 inches down from the top of the transom so I would be reluctant to raise them any.
 
Tom,
In your case, your Permatrim is already above the bottom of the boat when it is parallel to the bottom, so you would not raise it. The question is if you are getting any cavitation?

Driving the bow definatively down, is one of the goals of adding the Permatrim--this puts the "v" of the foreward lines of the boat into the chop, instead of the flatter bottom, aft. This is desirable only going into chop. Going down wind/chop/waves, putting the bow down can cause dangerous bow steering and a tendancy to broach. So down wind, you want the bow slightly up...
 
tpbrady":3oipviqh said:
Jay,

I get geometrically challenged at times so am having a hard time interpreting what Permatrim is saying. If I trim the motor down until the motor's cavitation plate is parallel with the bottom of the boat (using a 4' carpenter's level), the cavitation plate is about 3/4 inch above the plane of the bottom. As I continue to trim the motor down the leading edge of the cavitation plate approaches the top of the level and then ends up almost 1" below the top of the level when fully down. I almost never run with the motor fully down and with a Permatrim, that full down position would definitely drive the bow down into the water.

So the question is, with your motor trimmed to where the cavitation plate is parallel to the bottom of the boat, where is the cavitation plate in relation to the bottom? On the same plane, above the plane of the bottom, or below the plane of the bottom.

If I raised my motor any further, as the cavitation plate approaches a plane parallel to the bottom of the boat it would be in excess of 1 inch above the plane of the bottom. Besides that, I am not sure I am raise the motor any further as I am running out of transom. The top bolts are about 1.5 inches down from the top of the transom so I would be reluctant to raise them any.
Click to expand...

Hi Tom,
Hope your using the level as a straight edge, using it as a level will really mess you up. :wink:
I ran my motor all the way down/forward to make the measurement. I placed a 3 foot metal straight edge against the bottom of my cav plate, this plane fell about ¾ of an inch blow the bottom edge of my transom.
So to answer your question, when my cav plate is adjusted parallel with the bottom the boat, it’s still about 3/4”below the plane of the bottom.
Also, with my Permatrim installed I have to run the boat with motor in full down position, up trim only slows the boat down and raises the bow.

Last night, feeling restless watching TV I went outside and tackled the task of raising the motor one notch-about ¾”- took about an hour with my wife’s help.
I have 4 adjustment holes on top and slots for the bottom bolts. All I had to do is remove the top bolts, loosen the bottom bolts a little, place some blocks under the skeg, then raise the tongue of the trailer forcing the motor upward. When the next set of holes lined up I slid the top bolts in.
Of course I removed and resealed all the bolts especially paying attention to the bottom bolts, used a lot to sealant forcing it in where ever I could and so on.

I’m not convinced this change will make much difference but thought it worth a try. The only thing I’m worried about is running into cavitation problems, if that happen I’ll either reverse the process or install a stainless prop.
A 1 Propeller & Impeller Repair, 210 E Potter Dr, Anchorage, AK. Tel: 907-344-7767, these guys carry solas props and will work with me as I dial in which stainless prop fits my needs the best.

I like the KISS concept, helpfully I’ll be satisfied with the results and enjoy the rest of the summer.

Heading out of Whittier Sunday the 15th for 3 or 4 days to explore the knight Island Group and hopefully bring back a load of meat in the process. By then maybe most of the snow will be gone and we’ll be able to hike around the islands.
 
Jay,

I had the same problem when the motor was first rigged. It only ran all the way down and when I trimmed it up things slowed down. I moved it up one hole and everything was much better. The problem was it was the last hole.

I am running a Quicksilver 14P 3 blade stainless (Cabelas sells them). I like the Solas and have a couple but the 14P hit a nice operating spot on the BF90D. I lost some top end fuel economy but no top end speed, but gained a lot of fuel economy on the low end. I have a 15p 3 blade Power Tech Stainless if you want to try it and see how it does. PM me if you are interested. I have large selection of Honda props.
 
Tried the boat out last week after raising the motor one notch; the results were positive. I was able to trim the motor up for the first time and not loose speed, actually gained speed. At 5000 rpm and 23.3 on the gps I was able to gain about 2 mph after trimming the motor up to level on the indicator; bow height remained unchanged.
I still need to evaluate lower speed trim but so far the results look good.
Definitely want to install trim tabs, really like a level boat underway.
 
Jay,

I was out last weekend also on Saturday Night and Sunday. I was running with a Permatrim installed and learned quite a few things about how it worked.

a. I experimented with various trim tab combinations and motor tilt settings. I found the most efficient point at 14 mph for example was using some down tab and trimming the motor up until it was close to parallel with the flow of water.
b. I don't think the Permatrim will ever get on top of the water at slow speed operations on step (9-18 mph). However, at higher speeds it definitely comes up on top. I had maybe a .5 mph loss in top end.
c. The Permatrim gave much better control in a following sea of 1 to 2 feet allowing me to travel at a lower speed with the bow trimmed down slightly using the Permatrim. My choice in following seas was always to speed up to get better directional control. but that came at the risk of pounding on occasion. Now I can slow down or go fast and pounding wasn't a problem. In the heavier following seas on Sunday, I didn't experience any ventilation even though I had the motor trimmed up much further than normal.

I am still working with it, but so far it is a keeper.
 
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