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ContinuousWave: Whaler Performance
Raising Engine Height
|Author||Topic: Raising Engine Height|
posted 01-31-2001 06:23 PM ET (US)
I have a Johnson 88SPL on my Montauk. I think it is down too far on the transom by an inch or two. How difficult is it to raise the engine height? Will I need help? Shold my mechanic do it? How will I know if I have gone too far up? I am currently getting 39MPH top speed with a stainless OMC (black) 17 pitch. Also have a Doel-fin on. Hole shot, steering, acceleration are great. My main concerns are shallow water ability and top-end speed. Comments/suggestions please.
posted 01-31-2001 06:38 PM ET (US)
Trident, hook your boat to your vehicle so boat won't move when you lift engine. Back it under a tree limb or struss in your shop. Use a comberlong or chain hoist is better--pull up till you get slight tension. unscrew the four bolts and lift up(very easy). I have a 75 merc and doel fin and averaging 42mph. I gained 4mph by raising engine 2 notches(1 1/2 inches). My rpm went up 250 rpm. When I put a level on the bottom up my boat my cavitation plate is about 1 inch above the level(or bottom of boat) Hopes this helps. YOU CAN DO IT. Dennis
posted 01-31-2001 08:48 PM ET (US)
I think I'd rent (or borrow from the kid
down the block) an engine hoist. Your OB
may not be as heavy as a big block V8, but
I don't know that I'd trust a tree limb
(they come down by themselves around here
sometimes) or a truss in the garage.
And check the service manual for the right
posted 01-31-2001 08:48 PM ET (US)
forgot to tell you to be sure to recaulk around bolts.
posted 01-31-2001 09:36 PM ET (US)
Raising or lowering a large outboard is relatively easy, as long as your boat is on a trailer with a tongue jack and you can back the engines under a beam (or tree limb, I guess) that is strong enough to carry their weight. The method I am going to describe can also be used to insert a transom stetback jack. I have lifted the Merc 200's (415lbs) on my Outrage using this method. An actual lifting device is not necessary.
The idea is simple. Just HANG (not lift) the engine on a static wire cable or chain (not rope - it will stretch), and use the trailer tongue jack to raise or lower the TRANSOM as necessary. For raising an engine one or two bolt holes, well within the range of your tongue jack, do this: (2 persons are best for this job, although no strength or lifting is necessary) A lady or kid can be your helper.
1. You will first need to get your supplies together. The engine MFG's lifting eye (Merc's costs about $60 and threads into the top of the flywheel), some wire cable and cable clamps (4 or 6 for safety), from your local Ace Hardware,(adequate diameter to carry twice the engine weight - store will have tensile weight carrying rating.) An "S" hook for the end, to hook the engine lifting eye, and a short length of chain. The top end of your "hanging" cable will be looped over the beam and clamped, and the bottom end will have a small loop for the "S" hook, then a few adjusting chain links, then another "s" hook into the engine Eye.
2. Back the engine under your overhead beam, (BE SURE IT IS STRONG ENOUGH TO CARRY ENGINE WEIGHT) and drop the trailer tongue all the way down as low as it will go. This will raise the transom and engine as HIGH as it will go. Engine should be in the perfect vertical position to the ground. Then rig your wire loop over the beam, and adjust the total length so it is as tight as possible on the engine eye. You won't be able to get it totally taut, but that's ok. Inserting a few chain links really helps in getting it tight. Then RAISE the tongue jack (dropping your engine) just enough to tighten the slack on your hanging cable so that it is beginning to carry the complete weight of the engine (but not lifting the whole transom of the boat! - a few creaks and groans are good - that means you're transfering the engine weight to the cable) Now put some wood blocking under the skeg so the engine is supported here also, or at least can't drop more than 1/2". The idea is that the engine can't move down much and get away from you in case you haven't properly tensioned the cable.
3. Now loosen up your engine bolts carefully, and remove. You will find the engine totally hanging on the steel cable! Nothing has to be disconnected from the engine. As a matter of fact, all the cables will help keep it in position. This is a good time to clean up the transom under the engine, replace bent washers, add transom stiffeners, etc. Have your clear silicone caulking ready when you re-install the 1/2" SS engine bolts. Occassionally these lock nuts can freeze up on you, so have a hack saw available and a few spare bolts/nuts ready. Use some grease on the bolt shank before re-installing the locknut.
4. Now, raise your tongue jack some more, which will lower the transom, until the bolts will slide into the next LOWER engine bolt hole and into the transom holes. This, in effect, RAISES the engine on the transom. (Instead of lifting the engine, you're lowering the transom - easy to do with the trailer jack!) Caulk and bolt up tight, and you've got a higher engine. The reverse can be done if you want to DROP an engine, or if you get it up TOO high.
This whole thing sounds like a lot, but it will take less than an hour/engine. However, anybody going to the bother to do this, should at least consider inserting a $200 6" setback transom jack at this time. Then, you can easily adjust your engine height any time with out this bother. Be sure to get a ONE unit jack. The cheaper earlier designs have two distinct parts, and are not as easy to use.
So there you have it. Good luck, but be careful of doing it safely.
posted 02-01-2001 10:08 AM ET (US)
Thanks for the great information. I guess I can handle it. lhg- What brand/model jackplate do you suggest for my Montauk?
posted 02-01-2001 10:53 AM ET (US)
I just ordered a Cook Manufacturing Corp (CMC) model ML-65 which is a manual model (as opposed to hydraulic) but all you have to do is loosen 4 bolts on the side then use a socket on one nut to raise & lower the engine. It has a setback from the transom of 5 1/2" and has a 5" vertical adjustment. Also from this same company I ordered upper and lower transom washer plates on which they are engraving "Boston Whaler" on the top one. -- Manual Jack cost about $190 and the custom washer plates cost $60. Their number is 800-654-3697. Rex
posted 02-01-2001 11:40 AM ET (US)
This is one of those items where there are several good units out there, and the choice is purely personal. The CMC unit Rex mentions is supposed to be excellent, and they are a leader in the field. With theirs, the engine bolts are mostly concealed behind the side plates.
Look in the major catalogs such as Bass Pro and Cabelas for other brands. All of these have a large threaded center bolt shaft, that is turned with a prop wrench to raise and lower the engine. I use the Springfield Marine one piece unit, which works the same as the CMC, except the mounting bolts and engine bolts are exposed. But the unit looks smaller on the boat. Most brands come in either 1/2" anodized silver aluminium or black painted aluminium. In the Rendezvous section JimH shows a close up of one of these with a Yamaha 200 mounted on it.
The Springfield units are available in either 6, 10 or 12" setbacks. I think for a Montauk or smaller, I'd go with a 5"-6" setback like Rex is doing. For 18 Outrages and up, I'd go for the 12" setback. The transom stiffener bar, at least across the top bolts on the inside, is a good idea, since these things do add a little more stress to the transom.
You will be very happy with one of these. Be sure that your steering and cables can accomodate the setback.
posted 02-07-2001 07:16 AM ET (US)
I have just finished installing a Bob's Machine 4 in 1 manual jackplate #MJ5 with a 5" setback on my Montauk. I have an '84 Johnson 115 and it was mounted in the lowest position to the transom using the bolt holes that run from the inside of the transom. This would not allow me to raise the motor to the 3rd hole as many others have suggested. Our local Whaler dealer mounts a 6 degree wedge on it's new Montauks. The Bob's plate allows this same 6 degree of negative. The process was a lot easier than I expected. I did not even unhook the controls! I redrilled the mounting holes in the plate 1” to the outside. This allowed me to miss the drain holes in the splash well. This setback allowed me to raise the motor close to 3” without loosing water pressure. The results were dramatic! The boat now jumps up out of the water and rides higher on plane. I also gained 600 RPM. I highly recommend the change!
posted 02-07-2001 08:39 AM ET (US)
Jim F -- that's great news since I'm mounting an MJ5 on the 13 sport and was wondering just how much I could bring the motor up --- had speculated 2"- 2 1/2" so I should be in the ball park if you got 3" --
Think I will have to replace the steering cable it is an aweful tight fit now, and putting the motor out 5" don't think enough free play -- appears it might bind Tom
posted 02-07-2001 12:44 PM ET (US)
BigZ - I did not think I would have enough steering cable either, but it was not a problem at all. I did not get any binding despite the fact that it was stretched to it's limit.
posted 02-07-2001 12:53 PM ET (US)
Can anyone send me some pics of a manual jackplate installed on a Montauk?
posted 02-07-2001 06:31 PM ET (US)
If someone has pictures of their jackplate installation, I'd be glad to run these in CETACEA, then everyone can see them.
The picture of the setback plate in the Rendezvous article is a little hard to see the details, even though I tried to enhance it a bit. See
posted 02-07-2001 10:12 PM ET (US)
JimH & Trident,
It may be a couple of days, but I will sure send in a few photos.
posted 02-08-2001 09:27 AM ET (US)
Thanks Jim, looking forward to seeing the pics.
posted 02-08-2001 02:46 PM ET (US)
I will send Jim Complete photos of my boat too once all is finished.
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