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Repowering 2000 Dauntless 18

Posted: Wed Mar 29, 2023 8:57 am
by Paul180Dauntless
I may re-power my 2000 DAUNTLESS 18. It now has a Mercury 135-HP OptiMax. I HOPE to get a few more years out of that engine.

FOR PEOPLE WHO ALREADY HAVE RE-POWERED A c.2000 DAUNTLESS 18: give me recommendations for engines for a re-power.

Aside from the cost of a new engine, my biggest concern is weight distribution. The bow of the DAUNTLESS 18 rides high. I don't want to exaggerate that characteristic with a new engine that is heavier [than the Mercury 135-HP OptiMax which is believec to weigh 431-lbs]. I love the power I get from the 135-HP OptiMax.

Any advice would be great.

Re: Repowering 2000 180 Dauntless

Posted: Wed Mar 29, 2023 9:31 am
by Jefecinco
A smart propeller selection can eliminate or lessen a Dauntless hull's tendency for the bow to ride high.

Re: Repowering 2000 180 Dauntless

Posted: Wed Mar 29, 2023 9:36 am
by Paul180Dauntless
Jefecinco wrote:A smart propeller selection can eliminate or lessen a Dauntless hull's tendency for the bow to ride high.
Q1: Are you suggesting I buy a heavier 150-HP engine and use the right propeller?

Re: Repowering 2000 180 Dauntless

Posted: Wed Mar 29, 2023 9:59 am
by jimh
Paul180Dauntless wrote:FOR PEOPLE WHO ALREADY HAVE RE-POWERED A c.2000 DAUNTLESS 18: give me recommendations for engines for a re-power.
I don’t have a DAUNTLESS 18. I have not re-powered one.

Paul180Dauntless wrote: Any advice would be great.
To reduce the cost of a re-power, sell your 135-HP OptiMax while it is still running. That engine is built on the 2.5-liter V6 block which was a classically good design. If you wait until the engine has a problem, finding a buyer will be much harder.

The price of everything is going up due to unprecedented inflation. The longer you wait, the more a new engine will cost.

Once you put a new engine on a 23-year-old boat, you will never recoup those costs.

The market for new engines seems to be constrained. There is not much supply and demand is high.

You probably have 23-year-old remote controls and gauges. Consider getting new controls and new NMEA-2000 instrumentation. Consider overhauling the entire fuel system. Old hoses, old filters, and old fittings will cause harm—very expensive harm—to a new engine.

Re-powering when you have a working engine is irrational spending, but then so is boating in general.

Re: Repowering 2000 180 Dauntless

Posted: Wed Mar 29, 2023 2:53 pm
by Phil T
ENGINE WEIGHTS: Mercury 150 (455 lbs), Yamaha F150 (522 lbs) or Suzuki DF140 (419 lbs) with a quality three-bladed or four-bladed stainless steel propeller.

Calculate the weight difference with what you have now. Place that weight in the splashwell or stern to simulate the "New" weight.

If you have a battery in the stern, move it to the console.

Start saving your dollars (pennies not enough) as the re-power will run you $19,000 to $23,000 depending on rigging and propeller selection.

Re: Repowering 2000 180 Dauntless

Posted: Thu Mar 30, 2023 2:33 pm
by Paul180Dauntless
Q2: do you think I could get away with a 115-HP? [Buying a 115-HP engine] would save money and help with the weight distribution.

ASIDE: I'm hoping the OptiMax has enough life in her, but if I do have to re-power I think I want to keep this boat instead of starting over completely.

Re: Repowering 2000 180 Dauntless

Posted: Thu Mar 30, 2023 7:49 pm
by Phil T
I would not recommend a 115-HP four-stroke-power-cycle engine for [a 2000 180 DAUNTLESS]. The DF140 would be the most cost effective. A good four-bladed propeller and proper engine installation at two-holes up or three-holes-up will solve [the tendency for the bow to ride high] you are concerned about.

Re: Repowering 2000 Dauntless 18

Posted: Thu Mar 30, 2023 8:06 pm
by Paul180Dauntless
Thanks Phil, much appreciated.

Re: Repowering 2000 Dauntless 18

Posted: Fri Mar 31, 2023 3:27 am
by jimh
To re-power with a 115-HP four-stroke-power-cycle engine as a replacement for a 2.5-liter V6 two-stroke-power-cycle engine with air compressor and direct-injection would not be an equivalent powering of the boat, and, based on your comment that you “love the power [you] get from the 135-HP OptiMax” you would likely be disappointed with the new engine.

Re: Repowering 2000 Dauntless 18

Posted: Fri Mar 31, 2023 9:13 am
by Paul180Dauntless
jimh wrote:To re-power with a 115-HP four-stroke-power-cycle engine as a replacement for a 2.5-liter V6 two-stroke-power-cycle engine with air compressor and direct-injection would not be an equivalent powering of the boat, and, based on your comment that you “love the power [you] get from the 135-HP OptiMax” you would likely be disappointed with the new engine.


Thanks Jim, very helpful! I'll let you guys know how I make out.

Re: Repowering 2000 Dauntless 18

Posted: Tue Apr 04, 2023 9:15 am
by Lupi
Paul180Dauntless wrote:...biggest concern is weight distribution...
I know those [DAUNTLESS 18 boats] are stern heavy. I owned a Dauntless 16 that is based on same platform. A friend of mine has a 18 Dauntless, same as yours with same engine. I drive it some times

Look at the Mercury 115 Pro XS CT. This model has a large gear case with a large offer of propellers. This engines weighs 363-lbs, or 65-lbs less than your present OptiMax engine.

From my dealership I know [the Mercury 115 Pro XS CT] engine has torque and power, but I could not test it.

The Mercury 115 Pro XS CT could be a less expensive option; it would create better weight distribution.

Re: Repowering 2000 Dauntless 18

Posted: Thu Apr 06, 2023 10:54 am
by Paul180Dauntless
Lupi wrote:Maybe you can have a look as well on the Mercury 115 Pro XS CT.
Thanks Lupi. That engine might be something to consider.

I'm waiting for my mechanic to get back to me on the [condition of the present OptiMax 135-HP engine]. When I dropped off with the mechanic, he that [failure of the] the fuel injectors usually does-in these [the OptiMax engines] After running a compression test, if he thinks engine condition is good enough to be worth putting money into, he will recommend replacing the fuel injectors and rails. I haven't heard from him yet, but more information on that is coming.

Meanwhile I've gotten a lot of good insight here for me to consider.

Re: Repowering 2000 Dauntless 18

Posted: Wed May 03, 2023 1:57 pm
by Paul180Dauntless
My mechanic got back to me regarding my Mercury OptiMax 135-HP engine, and said that he could fix the engine and get me a few more years out of it for just over $5,000. He also said he could re-power [my DAUNTLESS 18] with a new Mercury 150-HP engine for $15,600.

Give me advice on whether to repair or re-power.

My 2000 18 Dauntless is in very good condition.

NEW TOPIC
Q3: in three years what will be the value of my boat?

Re: Repowering 2000 Dauntless 18

Posted: Wed May 03, 2023 2:05 pm
by Phil T
I would not spend $5,000 on the existing engine.

The quote for the new Mercury 150 Fourstoke reads low. Loose engine price typically runs $17,000, rigging is $2,000 including a stainless steel propeller, and installation is $1,500. Then add sales tax.

Get a separate detailed quote from another dealer before moving ahead.

Re: Repowering 2000 Dauntless 18

Posted: Wed May 03, 2023 3:03 pm
by Paul180Dauntless
Mercury 150-HP engine $13,600
Key Switch $315
Tax $835
Labor $850
Total $15,600

My guy said that he'd use all my current rigging, and use my proppeller from the my 135 to save money. He'd replace the boat's fuel lines so those would be new.

Q4: does this proposal seem reasonable?

Re: Repowering 2000 Dauntless 18

Posted: Thu May 04, 2023 9:55 am
by Lupi
Just keep in mind that the Mercury 150-HO engine is slightly heavier than the OptiMax 135-HP engine. You will gain some speed and acceleration from a standing start.

You mentioned, the boat rides high. Maybe a particular set-up can partially solve [the boat riding high].

Re: Repowering 2000 Dauntless 18

Posted: Thu May 04, 2023 11:26 am
by jimh
Paul180Dauntless wrote:Give me advice on whether to repair or re-power.
For me to spend your money is very easy, so I recommend you get a new engine.

Paul180Dauntless wrote:Aside from the cost of a new engine, my biggest concern is ...
This earlier comment suggests that money for a new engine is a concern.

You only live once, so if a new engine will improve your life and your enjoyment of boating, then get the new engine if you can afford it.

The quoted price for the engine installation sounds quite attractive for today's inflated prices.

Paul180Dauntless wrote:Q3: in three years what will be the value of my boat?
Once you put $16,000 on the transom of the boat you will not be able to recover all of that expense if you sell the boat. If you see a different boat in the next three years being something you want, don't lavish on this boat with a re-power.

Re: Repowering 2000 Dauntless 18

Posted: Thu May 04, 2023 11:29 am
by jimh
This discussion really has no data about performance, and the topic is now about the decision to repair or repower. For further discussion this thread is moved to THE GAM.

If this boat gets a repaired engine or new engine, then a new thread can begin in PERFORMANCE to discuss the performance of the boat with whichever engine is on its transom.

Re: Repowering 2000 Dauntless 18

Posted: Thu May 04, 2023 11:37 am
by Phil T
The gear ratio of the Opti is 2.00. The Mercury 150 Fourstroke is 1.92

Is the current propeller a four-bladed stainless propeller?

Where are the the new harnesses?

I would not reuse the old ones. If you reuse them you will not be able to network the engine with your plotter or MFD in the future. You will not be able to see the added information on your old gauges.

The binnacle is mechanical and 23 years old, so are the shift and throttle cables. Replace now and save yourself from retrofitting later.

What is the second quote?