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Author Topic:   Nantucket with Merc 115 four stroke is a joke.
klied posted 05-06-2005 04:26 PM ET (US)   Profile for klied   Send Email to klied  
Brand new 30k boat, 4 guys fishing in fresh water, and boat will not plane, even maxing the throttle. Maximum 20mph.

This must be the biggest joke in boat sales history. Did merc just have too many of these crappy engines that they needed to just get rid of them?

My local boston whaler dealer is going to love me.

Any suggestions?

Sal A posted 05-06-2005 04:46 PM ET (US)     Profile for Sal A  Send Email to Sal A     
You may not like my suggestion.

I, too, feel the Mercury 115 4 stroke is not suited for the 190 Nantucket. I searched and posted here before I bought the boat, and was advised to max out the hp. I didn't listen, instead relying on the advice of the salesman. It wasn't his fault; he is doing what he is paid to do. It was my fault. I repowered over the winter with a Yamaha F150 and analog guages and controls.

I sold the engine to a forum member here for $5200 and paid $12,000 all in for my new engine installed. It was an expensive lesson, but I know I will never make that mistake again. I also have an incredible boat now, where if I needed to sell it, I might at least find willing buyers.

Look at the Honda BF150, 150 Verado, Suzuki DF140, and the 150 Optimax. All good choices. Here is the engine on my transom:

LHG posted 05-06-2005 05:05 PM ET (US)     Profile for LHG    
Just remember, that engine powerhead is by Yamaha! The Merc 115 2-stroke has a lot more power. But in reality, the boat should have 150 on it.
kglinz posted 05-06-2005 05:13 PM ET (US)     Profile for kglinz  Send Email to kglinz     
There's probably more info on this boat, in this article, than any other Whaler. ..... Did you do a Seatest before you wrote to check.
Knot at Work posted 05-06-2005 05:14 PM ET (US)     Profile for Knot at Work  Send Email to Knot at Work     
And to think I called efduffer a troll...
klied posted 05-06-2005 05:34 PM ET (US)     Profile for klied  Send Email to klied     
I should have posted more details.......
4 guys fishing on a freshwater lake, at 5000' elevation. Boat will not plane out.

Would it be an easy fix to just change the prop? The boat seems to do fine at sea level. Which prop?

If it would only cost a few grand to swap the engine I would do it, but now the engine has 2 hours on it.

Sorry if original post sounded like a troll.

Boat was puchased in Orange County California.


wyeisland posted 05-06-2005 05:38 PM ET (US)     Profile for wyeisland  Send Email to wyeisland     
Get the Honda. Honda is an engine company. I have an optimax (225). It cost me about $4k in repair after 100 running hours. The Verado is totally untested. Ever wonder why all the other companies are not running superchargers?
Its too bad that Whaler is now tied to Mercury. It makes the new boats totally undesirable.
kglinz posted 05-06-2005 05:43 PM ET (US)     Profile for kglinz  Send Email to kglinz     
Even if you repower to a 150 you will probably need a prop change between sea level and 5000'. You'll lose around 20% of your power at 5000'. See if your dealer will lend you other props, of less pitch to try.
kglinz posted 05-06-2005 05:47 PM ET (US)     Profile for kglinz  Send Email to kglinz     
If you repower with a Verado 150 you will lose little power, with altitude increase, do to supercharging.
klied posted 05-06-2005 05:47 PM ET (US)     Profile for klied  Send Email to klied     
Good suggestion, thank you.
bluewaterpirate posted 05-06-2005 05:52 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
So Wyeisland

I'll bite ...... what did you do to the Optimax that caused 4K in damage after 100 hours that it wasn't covered by warranty????????

Cheers .......


Knot at Work posted 05-06-2005 06:50 PM ET (US)     Profile for Knot at Work  Send Email to Knot at Work     
Master Chief, I was going to ask the same thing.

Good attention to detail!


high sierra posted 05-06-2005 07:05 PM ET (US)     Profile for high sierra  Send Email to high sierra     
Klied,don't swap motors until you put the right prop on it

and test it. You should drop at least 4 inches in pitch as a start. I know. I live at 5500 feet and fish at Tahoe and other high altitude lakes. The 115 Merc and ALL other 4 stroke motors that are suggested have the same problem. Anyone at sea level does not realize how much power is sapped by thin air. Fuel injection is fine but does NOT solve the problem. Go for a prop change. high sierra

klied posted 05-06-2005 07:59 PM ET (US)     Profile for klied  Send Email to klied     
Thanks for the reply. I think the elevation is actually around 7000'. We fish Lake Crowley. Up towards your neck of the woods.
LHG posted 05-06-2005 08:48 PM ET (US)     Profile for LHG    
Ah, the rest of the story! I have seen that some engines need to be altered, or have different gear cases for high altitude operation. Check with Mercury customer service for mod's needed. Carbs need different jets, but i don't know about EFI.
Whalerider posted 05-06-2005 08:50 PM ET (US)     Profile for Whalerider  Send Email to Whalerider     

7000 ft!!!!! holy cow. You will need every bit of 150hp to be happy.
Heck...mine feels slightly underpowered at sea level with an Opti 150.

Other brands of boats of similar size and weight are rated to at least 200 hp, most to 225 hp. Boston Whaler limits their hulls for way too little horsepower (and admit it).

Do like Sal A, hang a Yammy 150-4 or if you can stand the wait(and $$$) the Verado 150 would be sweet.


p.s. I still think a 200 on back is really what a Nantucket should have.

bobeson posted 05-07-2005 12:22 PM ET (US)     Profile for bobeson  Send Email to bobeson     
klied - I'm sure you'll be able to sell your Merc 115hp EFI pretty easily - lots of folks, myself included, who got the Montauk 170 with 90hp 4-stroke engines are wishing they had the 115 EFI instead. The upgrade from 90 to 115 is particularly easy with these engines, since they are basically the same thing modulo EFI.
Perry posted 05-07-2005 09:30 PM ET (US)     Profile for Perry  Send Email to Perry     
The 25 inch Mercury 114 4 stroke that comes off the Nantucket might cause a problem fiting it to a Montauk 170.

I take delivery of my Nantucket next month. The dealer was willing to take off the 115 4 stroke and sell it on the side so I can repower before it gets off his lot. It cost me an extra 2 grand but I think it is well worth the money.

Yiddil posted 05-08-2005 01:54 AM ET (US)     Profile for Yiddil  Send Email to Yiddil     
2004 Nantucket w/ 115-2 is no joke...runs great!
highanddry posted 05-08-2005 02:48 AM ET (US)     Profile for highanddry  Send Email to highanddry     
At 7000 feet you probably only have about 80 horsepower. That is a very high altitude and outboards and most all boats and engines are really optimized for sealevel. At that altitude a 150 is probably barely making 115 horses. Yeah, I agree, it is a joke and the joke is on you if you actually expected good performance without swapping props etc at 7000 feet. LOL, good luck. hope it works out for you.
bigjohn1 posted 05-08-2005 08:02 AM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
klied, if swapping up to a bigger engine is not an option, as you already know, optimizing the prop is your only option. If you are going to continually run with that level of loading at that altitude, you may just have to scrap conventional prop wisdom and go with the smallest pitch prop you can then watch the tach very carefully so you don't over-rev your engine. You can have a second more conventionally pitched prop for when you are operating at normal altitudes. I am thinking if you install a Doelfin or other similar hydrofoil device on your engine and then switch to a 15P prop, this may give you the extra power you need. As stated though, you will have to watch the tach carefully when you are going this route to ensure you do not over-rev. I recall Aquanut saying when he ran a 15P ss prop on his 115efi equipped 170 Montauk, it just hit the rev limit of 6,100rpm for this engine. Considering his experience as a baseline and also considering you are pushing more weight with the same engine, maybe a 15P would be as close to perfect as you're going to get....but I am not sure, just thinking outloud. What pitch are you running now?
nolewhaler posted 05-18-2005 12:20 PM ET (US)     Profile for nolewhaler  Send Email to nolewhaler     
I have an OPTI-Max 135, and it is very well powered. Top end is 43 MPH (loaded with wife and two kids, and drinks). Planes in about 3.5 seconds. My brother has a Honda on his Proline. It is nice engine, but is a real dog when it comes to performance.....very slow to plane, and not much torque while on plane going thru heavy seas. My OPTI also beats his Honda on gas mileage!..his boat is about the same weight..and comparable horse power. They did have problems with the OPTI's when they first came out, the air-injectors...that problem has been corrected. Just my thoughts
Bulldog posted 05-18-2005 02:42 PM ET (US)     Profile for Bulldog  Send Email to Bulldog     
Before you change props and bolt on Doel-fins or anything. , I would talk to your dealer and see what he says he can do. You have two hours on a new boat and motor that cost a bit, perhaps he'll surprize you and help you out with the prop and/or a new motor. It is worth talking to him first, more so, if he knew where you were planning on boating. I'm sure he would love to know how you are bashing the boat he sold you on this forum, maybe he'll want to have you boast how great a guy he is also, after seting you up better!............Jack

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