1989 OUTRAGE 18, Suzuki DF140 Engine Mounting Height

Optimizing the performance of Boston Whaler boats
playedout
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1989 OUTRAGE 18, Suzuki DF140 Engine Mounting Height

Postby playedout » Tue May 30, 2023 12:37 pm

I need advice on engine mounting height before I start a trial-and-error approach.

Q1: what is a good initial engine mounting height for a SUZUKI DF140 on a 1989 OUTRAGE 18?

Q2: is an engine mounting height of two-holes-up a good starting engine mounting height for a SUZULI DF140 on a 1989 OUTRAGE 18?

BACK STORY: My dealer just installed a 2022 SUZUKI DF140 engine on my 1989 OUTRAGE 18 at in the lowest possible engine mounting height position. Based on some reading on the forum, I infer the general recommended engine mounting height for an engine on a 1989 OUTRAGE 18 is to be two-holes up.

The engine run time is now past the break-in period , and I have now been able to run the engine at full-throttle. The DF140 engine is throwing a significant amount of water, and steering is very at heavy at full-throttle engine speed. I infer both of these as indicative of needing to raise the engine mounting height to one-hole-up or to two-holes-up to reduce drag [created by the engine gear case in the water].

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Phil T
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Re: 1989 OUTRAGE 18, Suzuki DF140 Engine Mounting Height

Postby Phil T » Tue May 30, 2023 8:45 pm

You want the engine installed so the anti-ventilation plate is 1-1/2 to 2-inches above the bottom of the boat. Another way of expressing this: assuming the top engine bolt hole is 1-7/8 below the top of the transom, mount the engine two-holes-up; this will put the top bolt in the third hole counting down from the top.

You will want a Suzuki 14x22 Stainless propeller for the engine.

This information is a product of a dozen Outrage 18 owners I worked with on installing and configuring a DF140 since 2020.

Find another yard because they don't know what they are doing.

Raising the engine can be done with the boat on a trailer as a DIY with a second set of hands. I have the steps if you want them.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

playedout
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Joined: Thu Jul 14, 2022 6:44 am

Re: Engine height for 2022 Suzuki DF140 on '89 Outrage 18

Postby playedout » Wed May 31, 2023 6:32 am

Phil—thank you. That information is super-helpful.

Looks like I got the propeller selection right, but I will need to move up the engine mounting height as you suggest.

GIve me the steps for the DIY engine-raise, and I'll attempt to raise the engine this weekend.

jimh
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Re: 1989 OUTRAGE 18, Suzuki DF140 Engine Mounting Height

Postby jimh » Wed May 31, 2023 9:38 am

Mounting a modern outboard engine at the lowest possible engine mounting height is seldom going to be the optimum position.

Probably the least risk in choosing an initial engine mounting height would be at the one-hole-up position.

Starting at two-hole-up position can often work well, and if a change is needed, to lower the engine to one-hole-up may be easier than if raising the engine mounting height were needed.

DO IT YOURSELF ENGINE RAISING OR LOWERING

The typical do-it-yourself method of adjusting engine mounting height requires that the boat be on a trailer. The engine is secured to an overhead support; a stout tree limb is often used. The best method to retain the engine is to use the OEM engine flywheel attachment ring. If that hardware is not available, the engine can be secured to the overhead support with well placed strapping. As a further support, large wood blocks are usually placed under the engine skeg, but do not rely on the skeg to bear the entire weight of the engine.

With the engine secured to the overhead support and the blocks on the skeg, the engine mounting bolts are removed, while one or more helpers retain the engine in alignment with the transom. Another person operates the trailer tongue lift jack to raise or lower the boat transom to align the existing holes in the transom with the desired hole set in the engine mounting bracket. The engine mounting bolts are reinstalled and tightened. The trailer tongue jack is lowered to raise the transom, taking the load off the overhead support and the wood blocks, which are then removed. The smaller the engine and the lighter the engine weight, the more likely this type of procedure can be done successfully without needing to obtain the OEM engine lifting ring attachment for the flywheel.

The exact nature of the OEM flywheel lifting ring attachment varies with the manufacturer and engine model. Some are sold for under $30, which seems like a good investment if planning to raise or lower the engine mounting height.

Whenever the engine mounting bolts are removed and then reinstalled, care is necessary to insure that the bolts are properly sealed and watertight. This is particularly important in Boston Whaler boats which always use wood reinforcement in their transoms.

Hiring a boat yard or engine dealer to change the engine mounting height may only cost one hour of labor, which should be in the realm of $125. If the installing dealer is used to change the mounting height of a newly purchased engine, the dealer may be willing to change the engine mounting height as a courtesy or at a reduced cost.

jimh
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Re: 1989 OUTRAGE 18, Suzuki DF140 Engine Mounting Height

Postby jimh » Wed May 31, 2023 10:44 am

Engine mounting height is often specified as a method to alter engine full-throttle boat speed performance, but there are other considerations that must be taken into account. See the article

Considerations in Engine Mounting Height
https://continuouswave.com/forum/viewto ... f=7&t=6618

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Phil T
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Re: 1989 OUTRAGE 18, Suzuki DF140 Engine Mounting Height

Postby Phil T » Wed May 31, 2023 1:32 pm

METHOD TO RAISE ENGINE MOUNTING HEIGHT FOR HOME USE

Raising the [engine mounting height] us a do-it-yourself operation IF:
  • the engine mounting lower bolts are in the slots;
  • the boat is on a trailer; and
  • you can have someone help you at one stage.

A second set of hands is helpful to
  • monitor the work
  • hold the engine steady, and
  • operate the trailer tongue jack

If [a helper is] not available, make sure the nuts [on the lower engine mounting bolts] are only loosened enough for the [engine mounting] bracket to slide [up or down in the slots].

Steps:
  1. park trailer on firm and level ground;
  2. block front and back of all trailer wheels;
  3. place a block of wood on the ground below the skeg for protection
  4. lower the [trailer] tongue with the jack so you can position engine vertically
  5. center engine with steering wheel and tie off;
  6. remove any excess sealant around the bolts on the outside and inside of the transom;
  7. slightly loosen but do not remove the nuts on the lower mounting bolts so the engine can slide when raised;
  8. remove the nuts on the upper engine mounting bolts;
  9. gently tap the upper bolt heads to break the sealant hold and remove the bolts;
  10. raise the tongue with the jack so the transom holes align with the desired holes;
  11. insert marine sealant--NOT adhesive--into the upper hole from the inside of the boat and from the outside of the boat;
  12. insert upper bolts and washers and tighten nuts;
  13. wipe off excess sealant;
  14. reapply sealant to the outside of the lower bolt shaft in its new position[ and,
  15. tighten lower engine mounting bolt nuts.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
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Location: Michigan, Lower Peninsula
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Re: 1989 OUTRAGE 18, Suzuki DF140 Engine Mounting Height

Postby jimh » Mon Jun 05, 2023 6:02 pm

Before you attempt to raise the engine mounting height on your boat with a new engine, consider the cost of the new engine compared to the cost of having a dealer raise the engine.

For example, on my boat with a 225-HP engine, the cost of a new engine will be about $20,000. The cost to have the dealer change the engine mounting height will be about $125. From my perspective, spending $125 to avoid causing damage to what might be a $20,000 engine is a good plan to reduce risk of financial loss and loss of use of the boat for a month or more.