repower

[aya16]

about a year and a half ago I said I wanted to upgrade to a 90hp e-teck from my suz 50, reasons were I cant plane well, if at all with the suz, I have loaded the boat with all the essential, and non essential gear, So weight is up there a bit, but most of all from marina Del Rey to Catalina, if the the mac can get on plane while towing a dink, and sometimes thats a Boston whaler 13 foot, she rides and handles so much better than when the mac is not on plane.

Well I havent done it yet, wanted to wait for the eteck to get a few years on them to see if they are all what I thought they were. Well so far, everyone that has one seems happy. Now guess what? Mercury is in the two stroke clean machine outboard department now too.

My preference is a two stroke in an outboard, the 4 stroke has not lived up to the hype in my opinion. Quite, at Idle, yes, but the thing sounds like a 747 on take off, at full throttle. (well maybe not that loud)
But with valves and cam shafts and weight its just to complicated, so I like the two stroke outboard better.

Enter the mercury answer to the eteck. The optimax, at 50 pounds heavier than same hp eteck, and the eteck at 60 ponds heavier in the 90 to my suz 4 stroke, It would add 110 pounds to the back of my boat, basically not to bad. But wait, The merc is 50 pounds heavier but that weight goes across the 75- through the 115hp line they have available. Yep you guessed it, it would be the 115 for me.

Why so much power? Boats need all the power you can get in the weight class you want, unlike cars, a boat gets better gas mileage when more hp is used to accomplish the same task as a smaller engine making a boat go the same speed. The mac needs 17 mph to plane, my suz rarely gets that, A 90hp will do it as well as the eteck 60hp. So say I want 20mph, never going to happen with the suz, almost with a 60 eteck, for sure with a 90 eteck, but all the engines above, except the 90 will be going full throttle, a 115hp in the same weight class as the 90 and 75 will do it at optimum rpm, with less drag (on plane) that adds up to less gas burned.

Its not the price of gas as much as better control of the boat, as well as a less noise and being able to carry less gas for the same miles run, then the suz I use now. And the ability to up the throttle some when towing, say my Boston whaler to the island.

Why my choice of the optimax 115, I saw one on a fishing boat the other day, when started, it didnt smoke, I couldnt hear it from about 50 feet away at idle, and it looks way smaller in person then on the net. When the guy drove off, it had that sweet sound that two strokes have when working harder.

What am I going to do with the 50 suz? the engine on the whaler (1986) is tired, I think the 4 stroke 50 is ideal for that boat, many hours of trolling, way better gas mileage then the old two stroke on it now, and power tilt and trim, perfect.

That much hp on the mac is pushing it big time, so with the prudent careful use of the power its ideal for me, not for everyone for sure, but my situation it just might be ideal. Anyone want to chime in here what they think, Im all eyes.

If only the optimax came in white>>>>>
Mike

[Hardcrab]

Mike, some data points for you based on our experience.
2 stroke, 90hp TLDI Tohatsu, 14x11 prop, lighter loaded than you, unballasted is the set-up.
Run to Catalina at 17-18 knots, 45-4600 rpm (out of 5500 WOT possible), dinghy on deck, 10.5 to 11.5 gallons for the 30 nm trip.
How does that compare to your Suzi?

[Bobby T.-26X #4767]

i had a suzi 50 prior to upgrading to the Tohatsu 90.
with the 50 i achieved about 4.5mpg @ less than WOT, but was traveling at 14-15mph.
with the 90 on a 60 mile leg from Oceanside to Catalina I use 18 gallons while traveling @ 18-20mph (about as fast as one can go in the open ocean without damaging the boat).
so...my mpg's are down a bit, but it's a faster and easier ride.
IMHO...for my needs (ocean use), a 90 is more than sufficient.


Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

[aya16]

hard I use 13-14 gallons full throttle in that trip at about 13mph, rarely plane loud engine noise and fight the wheel. I agree 18mph or a little more the boats becomes very easy to manage.


Bobby I think the 90 is the perfect engine for these boats, your results are what I would expect from the 90, but dang the 90-115 are the same merc in the optimax, towing that whaler I get 11mph in the sail boat with the suz and burns 28+ gallons of fuel doing it, if I motor both ways. I have to top off in Catalina to have a safe margin of gas getting home. 18-20 mph is about it in the sea like you said, If that can be done at 3000 rpm the motor's humming nicely and I can actually hear myself talk to me.

I havent totally tossed out the eteck 90 in my mind, But Im certainly impressed with the optimax from what I have read and seen so far, and they have a three star rating too. If I can get it done before June I would do it with the merc now.

The thing about the 115 would be the versatility in being able to change props for more power towing, and still maintain the 3000 rpm and speed, (in theory anyway) I have had outboards all my life and always changed props to fit the occasion, skiing the 17 inch prop, fishing and running about the 19, Im hoping it works that way for the 115, but more like 13-14 pitch towing, 15 cruising, I like merc's I also like the eteck, I always thought any brand 90hp is I deal for the mac in two stroke. But to me if the 90 and 115 are the same engine, my thinking is get all you can get and use what you need. Thats hard to do if you need more than the engine can provide, like my suz 50, but it would be a heck of a whaler motor.

I think the 90 would serve me well, until I started to pull that 1000 pound whaler around, catalina just isnt the same with out the whaler, That boat has served me well for twenty years and bouncing off boats after an all night-er at the club in Catalina, getting back to the mother ship, havent sunk it yet..... Just kidding about that, 24 beers is my limit and I dont drive anymore after that.....
Mike

[seahouse]

Hi Aya --

I'm puzzeled about this part...

Why so much power? Boats need all the power you can get in the weight class you want, unlike cars, a boat gets better gas mileage when more hp is used to accomplish the same task as a smaller engine making a boat go the same speed.

There are so many more variables (prop pitch, number of blades, diameter & efficiency, RPM, combustion efficiency, bore, stroke, piston swept volume, manifold geometry, valve configuration, compression ratio, crank offset, reciprocating mass, gearing, valve timing & lift, ignition mapping, torque & power curve, lower unit profile, height on transom, etc. etc. etc.) between engines, even for the same hp rating, that I can't see how you can accurately gauge the fuel burn under that condition. There are so many things that are variable even if you were looking at one given engine on one given hull at one given speed. I do understand that you mean to stay somewhat above plane.

What is the source of your data for stating the above?

Regards.

[aya16]

Hi sea horse, just experience, One example is a cuddy cabin I owned that had an 85 hp outboard that would top speed at 35 mph at 5000 rpm, when I replaced the motor for a 135hp, the 135 would do 35 mph at 3500 rpm, in the mean time it sucked about half the gas doing it, of course when you put the throttle down and ran at 50mph (new top speed) it drained the gas tank pretty good.

If you look at the examples above with others 90's you can see they are getting better mileage then I am with my 50, bobby gets or got way better millage from his 50 then I do, mine is more like 2.18 mpg although I stated 13-14 gallons to go 35 miles, that was a guess, now that I think about it more, I take on about 4 gallons in the second 12 gallon tank, and fill the 1st 12 gallon tank most of the time I make the trip over to the island, then top off. So its more like 16 gallons, but it does vary sometimes.

Im not going to worry about all the details because even if the new engine gets the same or a little worse I dont care, at least it will do the job better. By the way Im still on the fence about what engine, I read and liked the optimax I saw in person, but now have read other things about them not to my liking, any one have one I would like to know what they have experienced. Merc is probably the easiest to get parts for and have it fixed, but the e teck guys I know love them. So we will see. The 5 year warranty isnt bad either for the merc and e teck right now.

As far as the 115 or 90, if its the same engine Ill always go with the more hp, as the case for the merc, in fact the optimax 75-90-115 are the same engine, I want an engine that I dont have to try and squeeze every pony out of to do the job. I know that some people dont care to have the power on their mac, dont need it either, but in my case I do, I have sailed with guys that have 90's and they do as good or better sailing, so the weight isnt a problem.

In fact crab did some tweaking of his rudders and has a 90 and I think his boat is faster than mine SAILING If I remember correctly. Right now Im ok with the 115 although it sounds very large for the mac, in reality its a mid size engine for 18 foot small craft, think 4 stroke 75hp, thats about the same weight.

Its all good, got to help the economy you know......
Mike

[seahouse]

Hi Aya --

Interesting.

A bonus of having the larger engine is that it should have improved longevity if it is not used to its max.

(Actually the alias is seaHOUSE, not seahorse - I only make this point because I noticed that there is a seahorse on this forum.)

[aya16]

Sorry seahouse should have closed one eye when I read the name. Longevity wow, when I bought my new 13 foot Boston whaler in 1986 I had no engine for it, but was planning to get one and install it my self.
A guy at work I told, about getting the new whaler said he had a couple old johnson's from the fifty's I could have free. He said they sat in his barn up north for years and next time he went up to the farm he would bring em back.

Sure enough he gives me two 35 horse power 195something white electric shift motors, all kinds of critters lived in them, full of nests and straw. Anyway I cleaned them up, played with them, installed the best one on the whaler and it fired right up. Shifted and ran good. I still intended to buy a new engine for the boat, but what the heck. I told my wife as soon as the engine blows Ill buy a new one. The thing looked like it came from area 51 and was butt ugly. I ran that thing for a year hard, trying to break it, but no, it wouldnt break. I ended up finding a good deal on a fifty horse new and bought it, took the Johnson off, sold it to a friend for a 100 bucks and it ran for two more years before he sold his boat. It still may be running!!!!!!

Set aside the horrible gas millage and the smoke and pollution, those old simple two strokes were very dependable back then up to the 90's when they started cleaning them up and made them very complicated.
Who knows how long these new ones will last.

I still wish the merc came in white, I might have it painted though, if I get it.
Mike

[K9Kampers]

I still wish the merc came in white...

Here ya go Aya...

[aya16]

Hi K9 I should go to ebay and find one, bet I could google up 1950's pix of Catalina and find many of those ole motors sitting on the transoms of boats tied to the very same buoys I use now, well same spots any way.


Side note: Doing some checking some more, seahouse, I found some interesting data on the 115 merc. it was tested on a 24 foot pontoon boat with a 15 inch pitch prop. I figure its about the same results for the mac, not perfect but close. At 4000 rpm they got 20mph, a little more rpm then I thought it should do, but anyway what blew me away was the gpm chart at that rpm and speed. 4.4 mpg at that rpm, put that into my numbers I will see, its basically using 7.95 gallons for a 35 mile trip. Thats absurd, considering Im using 16 gallons now at a far less speed.
http://www.mercurymarine.com/look_deepe ... max75115=5


Now thats definitely ideal situations and even if I burned say, 12 gallons (which is a whopping 4 gallons more) as some of the other guys here with their 90's Im looking at replacing the two 12 gallon tanks to two 9 gallons which is a savings of 20 some pounds of fuel weight. Like I said I dont really care about fuel millage unless I have to carry more fuel for the bigger engine, Im just looking for a range of 35 miles with a margin of 15 percent or so extra fuel.

If the mac gets the same performance they got with the 24 foot pontoon boat Im looking at a top speed of 29 mph, of which Ill never see in the ocean, unless of course were talking about absolutly flat seas, but even then thats to fast for any boat in an ocean full of surprises. But at 4000 rpm Its a nice two stroke purrr instead of a screaming 4 stroke at 5500 rpm. More sail boat like.

As you can tell Im getting jazzed with this idea, I wonder if merc would build me an engine and paint it white at the factory????? Dont really want to do a rattle can job, on a new engine.
I guess at this point Mike Inmon should step in here and chime in. I know his views about the bigger engines, and the factory certainly wouldnt condone such an engine, but I wonder if they would give it straight here as far as taking an engine that is exactly the same thing as a 75hp with a little boost in power, we are not that far from the 60 e teck they used to recommend, except horse power. Weight and size is about the same.

I dont think it would change my mind but to be fair to others that might consider this, Mikes views would be important to have on this thread, I see no down side but Im blinded a little with excitement.
Mike

[Bobby T.-26X #4767]

if you want white, go w/ Etec 90.
also, have you received price quotes for:
- Merc 115?
- Merc 90?
- Etec 90?

i realize that prefer a new tech 2-stroke over 4-stroke, but...
- would you consider the new Honda V-Tec 90?

Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

[Divecoz]

This has been discussed a lot here. BUT... you can BEEF up the transom that does nothing for the design of the hull!
A hull that was never meant to safely run faster than what mph?
Don't forget we have a big heavy 30 foot long stick aimed at the sky?
I lived thru a minor crash into a solid object / Marker piling. What will happen when this boat exceeds the maximum speed it was meant to operate at? On glass no doubt it will be fine to a point, but if anything goes less than perfect? Less than I perfect days on the water even moments on the water is when things............. happen. Just a thought....

[seahouse]

Thanks - Interesting link, Aya.

I especially like those engines that, according to the chart, use zero GPH at 1000 RPM. (Just a graphics "typo" I suspect).

Im looking at replacing the two 12 gallon tanks to two 9 gallons which is a savings of 20 some pounds of fuel weight.

Unless you're looking at saving volume in the boat, why not just put 9 gallons in the 12 gallon tanks, (almost same weight)? Then you also retain the capability of a larger reserve if you ever want to go on a longer trip between fuel stops.

My opinion - You should go for the 115 and tell us first hand what your fuel burn is! Inquiring minds want to know.

[aya16]

I did it, Placed the order for the 115 merc. should be installed in 2 weeks. tuff decision, as the eteck was my choice for over two years. Trying to find and eteck turned into a little hassle as most all dealers are merc. So I think the choice of the merc was better just for the resaon. The engine can be serviced and repaired if need be, three miles from the boat. I still like the eteck allot though.

Yeah Bobby checked the prices of the eteck and mercs, the eteck are almost a thousand dollars more than the merc 90, that is if I could get one, seems I can order one on the net, but not to many dealers here HAVE them. I havent checked the hondas at all, I assume they are good motors, but again the 4 stroke.

Divecoz I feel as you, that people can get into trouble pushing these boats past thier intended speeds, Why I wouldnt recommend any one put a bigger motor just to go way faster. I think in most cases mac would be serving their customers better if they would only recommend a little more hp. The 50 just doesnt cut it for me. But if I didnt have a use for the suz 50 I would not have bought the new engine, tomorrow I start taking the engine off the whaler.

seahouse great gas mileage at 1000 rpm!!!!!!. Has the problem with tempo tanks being discontinued, been solved? I have two 12 gallons starting to show their age, one of the reasons I mentioned the two 9'S also.

This was an expensive endeavor for sure the cost, when all said and done, is at 11600. I could save a lot installing it my self, but I think The dealer, who has rigged macs before by the way, is fair and it includes taking the old engine off with all the parts, mounting it and bolting it to the whaler. Ill do the rigging after that ON THE WHALER, merc also said that a dealer needs to install it to maintain the warranty. That warranty is 5 years.

Im looking at around the 24th when its all done, in time to break it in and a trip to Catalina on the 1st. The biggest advantage I see for picking the merc over all others is two things, merc shops are every where, and the other just for the mac, mercs 75hp-90-hp and 115hp are identical engines as far as phisical size and weight. They all share the same engine. They all are three star carb rated, which means they can even be used on lake tahoe if I wanted too, as well as any lake in calif. The cost difference is about 300 between them all.

I have to run the engine up during the ten hour break in at full throttle, Or 5500 rpm at times, My thoughts are to use a smaller pitch prop and just keep the motor at that rpm when its time to do it, instead of worp speed on the mac.... Any one have any ideas about this?????
Mike

[2BonC]

http://www.mercurymarine.com/look_deepe ... max75115=5

I assume the graph there is dealing with SM not with NM

Rainer