How does a guy raise the motor one hole?

[Rapaleye]

I follow this board fairly often. I have often heard you guys talking about raising the motor up one hole in order to gain some RPM on the outboard.
Well I think I finally have the right prop on my new boat. I am running a Solas Alcup 3 13.25" by 17 pitch. I get about 5500 RPM at full trim and my Suzuki 70 4 stroke is rated for up to 5800 RPM. I have good hole shot and am just wondering if I can get another 1-200 RPM out of the motor. Currently the engine is where it was mounted by the dealer, the second hole of 5 (I could raise the motor 3 more). The cavitation plate of the engine is about 1/2 inch above the very lowest point of the boat keel.
What I am wondering is how does a person actually go about "raising" the engine. My engine weighs 330 lbs. Do I need to hook a chain fall to it for lifting it? For what it is worth the top two bolts will have to be removed to get them in the new holes. The bottom two bolts are in slots so they could just be loosened and slid up.
Any help you can provide is much appreciated.
Jim

[Tom B]

You will need an engine hoist and some chains. I have not done a Suzuki, but with OMC and Yam, there are rings on the motor that you can but the hooks in for lifting. With Merc, there is a "lifting ring" that gets screwed into the top of the flywheel. Be sure to torque the mounting bolts to spec and you should be good to go.

Tom B

[SnellTier]

Guys, if I DO move the motor, what do I do with the steering hookups?? Will I have to move them also?

I can rig a hand-hoist in my garage trusses to take the 225 pound weight of my 75 hp engine, I think. But what about the other hookups? Do I run into problems? I have never done this.

[PJM]

Rapaleye

I saw a guy un a parking lot testing different prop and engine heights move it up in a matter of minutes. He put a block of wood under the skag, took out the top bolts loosen the bottom ones and used his tongue jack to lift up the front of the boat and the motor moved up on the back of the tramsom. For some rason he had it unhooked from his truck and the reason he gave is the boat has to move in order for the motor to move. I sam him do this 3 times with a 200 OPTI in a parking lot and it seem to work fine. He said he has done it this way for years with no problems.

[FIshing Junky]

I've done this several times myself. Works great. Junky....

[moreyes]

I to have put a couple of blocks under the skeg and raised the jack, just leave the loosen the bolts in the slid hole and remove the others, works best with two people.

GOOD FISHUN, KLH

[Rapaleye]

I figured there had to be an easier way than an overhead chainfall. Thanks for the great idea guys.
Jim

[SearchingForInfo]

I am confused. What is the effect of raising the motor and what is the effect of lowering it?

Raising it raises RPM obtained, apparently. So does lowering it lower RPM obtained? Does one just experiment to see the effect on hole shot, handling, and top end or are these sort of predictable in a "this USUALLY is the effect" sort of way?

[Nofish]

Howdy,

Make sure you chock both sides of the trailer wheels when you do this. Bass tourney guys have been doing this for years to dial in a new rig.

Have fun........R

[Nofish]

Howdy Tomd!

You should not have to worry about any hookups. you are only lifting the motor one bolt hole.

Chock the trailer tires on both sides. If you use the hoist, pull out the bolts and hoist the motor up one set of holes. Silicone the holes silly with Marine Grade silicone and reinstall the bolts. Clean up any excess silicone and you should be done.

Have a buddy assist you by holding the motor from swinging or twisting on the hoist etc....

Have fun........R

[Nolt]

I have a Alumacraft Tournament Pro 170 with a Suzuki 115 4 stroke. I had the dealer raise the motor 1 hole so I could get more top end speed. They also put a 20 pitch ss prop on. I still only get 36 mph WOT at 5700 rpms. I can barely trim the motor as it porpoises right away. Could this be caused by raising the motor 1 hole? The motor still seems to sit low in the water. The water is barely below the pee holes. Is low top end the result of having the wrong prop?

[Nofish]

Howdy Nolt.

I'm not sure what you mean by the water being barely below the pee holes. Do you mean the exhaust ports?

What hole is your motor mounted in? I don't think a dealer would mount a motor too high, but ya never know.

How is your boat loaded? Sometimes too much weight forward will cause porposing. Some boats are very suseptible(sp) to weight distribution.

Most boats will have a speed where they are inclined to porpose.

One thing to check, where is your cavitation plate in regards to the bottom of the boat? You should be a hair below the bottom of the boat. If you are level with, or above the bottom of the boat at full trim, this could be the problem.

5700 rpm does not sound too low or too high in RPM's without some more background info.

What RPM did you turn and with what prop before you made the changes? And what was your top speed then.

How are you measuring top speed? GPS? Radar? Dash Speedo?

In my past experience, a 20 pitch prop may be a little too tall for a 115. You need to talk to the dealer (service dept., there in)and find out what the optimum rpm is for that motor. Every Motor has an operating range, but also has a point on the horsepower curve that affords optimum power.

RPM is not always best at it's highest point. I have had rigs that gave the best top end in the low end of the RPM range and some that worked best at the very top end of the RPM range.

I didn't mean to play 50 questions, but I found it hard to offer much advice with the peramiters you supplied.

Have fun.............R

[KP]

Putting all the motor weight on the skeg can potentially cause damage. I have done it that way but not anymore. I built a U-Shaped support out of 2x4's and put it under the motor mount. Then I use the tougue jack to raise or lower the motor. I have also braced under the cavitation plate but stopped doing that.

Depending on the boat, you can go an inch or two above the bottom of the hull. However going too high does effect how much trim you can use. On my boat I can't go any higher than the bottom of the hull.

[Rapaleye]

KP,
I tried the blocks under the skeg but I believe the Silicone/marine adhesive is holding the mounting bracket in place. I cranked the jack more than 1 inch and the bolt holes hadn't moved any. I finally gave up for fear of doing damage to the skeg.
Can you describe in a little more detal the U shaped jig you made? I assume you have a 2x4 under each side of the motor bracket (probably in line with the bolt holes?). Did you have to attach them to the bracket in any way to avoid them slipping out?
Any additional help would be appreciated
Jim

[Rapaleye]

Nolt,
I am by no means a proping expert, but here is my assessment. If you do go up a hole or two to get more RPM, even if you reach the max. of 6000 for that motor you will only gain about 1.5 mph. What is working against you is that your lower unit gear ration is 2.59:1, it is a powerful gear box but a slow one. Your major hope for gaining speed is to go up on prop pitch, and use raising the motor to gain RPM then. You can use the following Prop calculator to try to estimate.
http://www.rbbi.com/folders/prop/propcalc.htm

It looks like you are getting around 10% prop slip right now. Unfortunately you may find that if you go up more in pitch you will get more slip and gain very little. Or you may loose hole shot or both. That is what happended to me. When I moved to a 19 pitch I was getting the same top end as a 15 pitch. At 17 pitch I am getting good hole shot, and more speed than the 15 pitch. Now it is a game of trying to get more RPM.
Hope this helps.

[KP]

First of all, I always cut around the silicone sealant with a razor knife and dig out all the silicone with a flat head screw driver. I also peel away all the silicone from around the mounting plate.

I have a base 2x2 a little wider than the mount, two vertical 2x4's turned so the wide edge is under the edges of the mount, and a 2x4 brace in the middle. I have the length cut so I can wedge it under the mount, on the same angel as the transom, when the tongue jack is all the way down. As you crank the jack up, the weight of the motor keeps the support from sliding out. Using the 2x2 bottom allows it to tilt as the boat and motor tilts. I also have a 1x1 and a 2x2 to slip between the motor and transom top in case the support does slide out.

I've also used a similar support placed in the same manner but used my neighbors floor jack to lift the motor. That way is a little easier but I've done it so many times, they're both easy. It helps to have another person to steady the motor just in case but the bottom bolts keeps anything drastic from happening.

Keep in mind, this is on a 220 pound motor and a Lund aluminum boat. I don't know how it would work with a heavier motor on a fiberglass boat.

[KP]

I played with raising my motor and trim angels using a basic aluminum 12 pitch prop as my baseline prop. Once my RPM's got to the 6100 Max allowed on my motor, I moved up to a basic aluminum 13 pitch. The 13 works OK with just me in the boat but I like the overall performance of the 12 pitch. Now I'm going to have a SS prop made to eek out a little more MPH and not loose hole shot. If you mess with props first and then change motor heights, you may find you've wasted a lot of money on the wrong prop.