Forum: WHALER
  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Performance
  90 HP Yamaha 4 stroke on Montauk 17

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   90 HP Yamaha 4 stroke on Montauk 17
MnFast posted 07-18-2003 06:04 PM ET (US)   Profile for MnFast   Send Email to MnFast  
The V4 90 hp Evinrude died on my late 80's Montauk and though I can get it rebuilt, I hate to spend money on an old horse, so I am thinking of buying (ouch) one of those new 4-stroke 90 Yamaha outboards. It looks a lot bigger and I presume a lot heavier than the Evinrude. Does anyone have any comments or experience using this on a Montauk?
I hate spending that kind of money on a new outboard too, but if it will give me great performance, is not too heavy, etc. then I guess I will bite. But, if anyone out there has any negatives they wish to share, please do so.
Otherwise I will to ahead and buy one and then report how I like it.
Thanks for any input.
JBCornwell posted 07-18-2003 10:02 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Hi, MNFast.

The 4 stroke Yamaha is a fine engine. . . .for a carbed, 358lb engine.

There are better choices. It doesn't make sense to me to buy a carbed 4 stroke when there are so many better, computer controlled, EFI 4 strokes available.

The Suzuki DF70/Johnson 70 EFI 4 stroke is an excellent choice for a Montauk. Many members here have this combination and are very happy with it (that includes JB). Upper 30s WOT is easily available with this engine and its drivability is superb.

Other options are the Mercury EFI 4 strokes in the 50-60hp range.

If you don't mind pushing the weight carrying ability of the Montauk transom, the Suzuki EFI DF90 and DF115 and the Yamaha and Mercury EFI F115s are around 415lb.

Bottom line? I would avoid a carbed 4 stroke in favor of EFI. My recommendation? Suzuki/Johnson 70.

Red sky at night. . .
JB

Bigshot posted 07-18-2003 11:22 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
If not getting 3mph more top end and saving about $1500 are important to you, get the Johnson/Suzuki 70hp. Both me and JB get about 39mph and about 2.5gph at cruise. Phenomenal engine and boat combo. You can use your old controls, etc if you get the Johnson.....saves another $500 easy. Run a 17" SST prop which you might already have and save another $400. You make the choice but I will gladly supply a performance report upon requisition of one.
MnFast posted 07-19-2003 05:30 PM ET (US)     Profile for MnFast  Send Email to MnFast     
Thanks guys, I really appreciate the feedback. Here are some more of my thoughts:
The Evinrude that went bad is old enough so that I have to put on new controls anyway to match the new engines, so that cost is a given, I am told.
I hear nothing but good about the Yamahas and that intrigues me. I also like the idea of having as much horse power as I can. As you know the Montauk is rated for 100, so 90 seems the way to go and 115 seems way too big (and heavy. The V4 Evinrude 90 that I had was very fast out of the hole and top end performance was very good especially when alone. I am told that I might lose some "out of the hole" performance with the Yamaha 90, but on the top end it will be similar. I want the speed and I also understand that the fuel economy is expected to be much better - a very nice bonus.
So, for the speed potential, I figure the 70 will not be as fast. Is there really only a 3 mph top end difference as Bigshot wrote and how does he know this?
Regarding a Johnson/Suzuki 90 HP 4 strk, it costs more than the Yamaha and I think I remember it might be heavier too.
I am getting recommendations to go with a 70 for a number of reasons, which is good info, but I have not heard of anyone actually buying and trying a 90 Yamaha 4 stroke on a Montauk of late 80 vintage. I would really like to read an observation rather than an inference, if there is one.
Those who have purchased 70's tried them out and were satisfied. Has anyone actually purchased a 90 and tried it out? I have recently seen the 90 Yamaha on a work boat in service and I was impressed with the quietness, etc., but because it is on a quite different vessel than my Montauk, I cannot gain any performance observations from it. The owners love it. The only other observation is that it looks much bigger than the V4 (and it is heavier) - so I wonder if it is too heavy and it will make the boat squat too much. But, I am over 200 lbs and when I stood at the transom next to the Evinrude 90 I had, I don't remember it squatting unreasonably with the combined weight of me and the motor which is less than a Yamaha 90.
So, that is my quest. Thanks for your comments and more will be well received.
MnFast posted 07-19-2003 05:30 PM ET (US)     Profile for MnFast  Send Email to MnFast     
Thanks guys, I really appreciate the feedback. Here are some more of my thoughts:
The Evinrude that went bad is old enough so that I have to put on new controls anyway to match the new engines, so that cost is a given, I am told.
I hear nothing but good about the Yamahas and that intrigues me. I also like the idea of having as much horse power as I can. As you know the Montauk is rated for 100, so 90 seems the way to go and 115 seems way too big (and heavy. The V4 Evinrude 90 that I had was very fast out of the hole and top end performance was very good especially when alone. I am told that I might lose some "out of the hole" performance with the Yamaha 90, but on the top end it will be similar. I want the speed and I also understand that the fuel economy is expected to be much better - a very nice bonus.
So, for the speed potential, I figure the 70 will not be as fast. Is there really only a 3 mph top end difference as Bigshot wrote and how does he know this?
Regarding a Johnson/Suzuki 90 HP 4 strk, it costs more than the Yamaha and I think I remember it might be heavier too.
I am getting recommendations to go with a 70 for a number of reasons, which is good info, but I have not heard of anyone actually buying and trying a 90 Yamaha 4 stroke on a Montauk of late 80 vintage. I would really like to read an observation rather than an inference, if there is one.
Those who have purchased 70's tried them out and were satisfied. Has anyone actually purchased a 90 and tried it out? I have recently seen the 90 Yamaha on a work boat in service and I was impressed with the quietness, etc., but because it is on a quite different vessel than my Montauk, I cannot gain any performance observations from it. The owners love it. The only other observation is that it looks much bigger than the V4 (and it is heavier) - so I wonder if it is too heavy and it will make the boat squat too much. But, I am over 200 lbs and when I stood at the transom next to the Evinrude 90 I had, I don't remember it squatting unreasonably with the combined weight of me and the motor which is less than a Yamaha 90.
So, that is my quest. Thanks for your comments and more will be well received.
tully_mars posted 07-19-2003 11:37 PM ET (US)     Profile for tully_mars  Send Email to tully_mars     
I would not spend the money for it, it doesn't benefit you in very many ways to have the 4 stroke 90. If you look on Yamaha's web site at their performance comparisons on the 90 2s and the 90 4s, on identical boats, they get almost the same gas mileage.

Also, as a rule of thumb the 2s engine has always generated more torque than a 4s engine can. Thus your performance with a 90 Yamaha might not be as good as the 2s 90, which is one of the perfect motors for a montauk.

I was going to re-power my Montauk just as you were, but at an almost $3k-$4k more for the 4s and almost no difference in gas mileage I couldn't justify it. However, I didn't get a 90 2s yamaha because they were backordered 6 months in my area. I ended up with a 75 FICHT Evinrude which gets outstanding mileage and has tremondous torque. It also had a better warranty than the Yahama, 3 years full parts and labor. I got the FICHT for $100 more than the 2s 90 Yamaha and with the v-4 60 looper it can pull me on slalom skiing no problem.

Tully Mars

JBCornwell posted 07-20-2003 12:21 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Hi, TM.

I beg to differ, sir.

Your "Rule of thumb" is a myth. Call it a myth of thumb.

Hp is a function of torque and rpm. To make the same HP at the same rpm, the 4s must make the same torque. Isaac Newton says so. If one engine must turn a few more rpm to make the same HP, a small difference in gearing puts the same torque at the prop.

The 90 2s Yamaha is only 70ci. It is very unlikely to match torque curves with the 97ci. "90" 4s (previously rated 100hp), even if it is carbed.

Show me a user of a computer managed, EFI 4 stroke that would go back to any 2 stroke?

Been there, Tully, done that. Have you?

Red sky at night. . .
JB

dogfish2 posted 07-20-2003 12:48 PM ET (US)     Profile for dogfish2  Send Email to dogfish2     
I agree with the "experts" and would like to add to their comments from my personal experience. A 90 4s MERC was delivered with my Montauk. The motor ran well but a carburated engine just cannot be compared to a DFI or EFI 4 stroke. The 70 4s Susuki/Johnson is a great engine. But, for my personal uses, I wanted more speed and power and opted for a 115 4s MERC (same controls). It, too, is a superb engine, and weighs the same as the 90 4s. Top speed @ WOT is 47 mph (GPS, but cruises great at 30-35 mph, 3500-4000 rpms. In my opinion, DFI or EFI 4-stroke is the way to go.
Perry posted 07-20-2003 03:41 PM ET (US)     Profile for Perry  Send Email to Perry     
I'm going to play devil's advocate here. Don’t get me wrong, FI is great and more efficient but I'm tired of people saying not to waste their time buying a carbed engine. The finest FI systems in the world have ample failures of components like mass airflow sensors, pressure sensors, temp sensors, injector spray problems and high & low pressure pumps. However, carburators are simple, easy and fast (less costly) to diagnose and repair. In the case of Honda or Yamaha, who have decades of multiple carburator experience have some of the best, trouble free and durable carburators in the world. A little water or debris in a fuel injection system and it will cost you hundreds of dollars for repairs, and won't be covered under warranty. If you get the same in a carb system, a filter, maybe a gasket set or two and some compressed air and you’re fishing again.

Cold starts are a simple; activate choke...turn the ignition key...crank…and the engine starts! High idle for 5-15 seconds depending on temp and I'm cruising away from the ramp. Hot starts are a simple twist of the key and 1-2 seconds of crank time immediately to a smooth idle. Honestly, my carburated 4 stroke has started, idled, ran and performed identical to a similar 4 stroke fuel injected motor EXCEPT with the following differences.

1. I have to lift a choke lever and hold at the desired high RPM for cold starts.

2. I've had to get my carbs synchronized at the 20 hr. break-in service.

3. A carburator adjustment CHECK is called for every 100 hours with or without possible adjustment.

I guy I boat with has the same boat as mine but has a 90 Suzuki EFI 4 stroke. I have a Honda 90. Hole shot and top speed are almost identical. If I had a choice, I would probably go with EFI but a carbed motor is not the end of the world.

JBCornwell posted 07-20-2003 05:16 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Dogfish.

I think if you will check you will find that your 115 EFI Mercury 4 stroke weighs 416lb, 60lb more than the carbed 90 4 stroke, which is listed at 358lb.

Red sky at night. . .
JB

Jarhead posted 07-20-2003 05:43 PM ET (US)     Profile for Jarhead  Send Email to Jarhead     
Hey JB.
My '03 Mercury Outboard catalog lists the 115 EFI, 90 and the 75hp fourstrokes at 386lbs dry weight.
JBCornwell posted 07-20-2003 08:07 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
I saw that, too, Jarhead, but don't believe it.

The 115 is EFI, the 90 and 75 are not. Virtually every other EFI 4 stroke engine on the market outweighs any carbed version on the same block by many pounds. Merc and Yamaha are examples, Honda is another.

The numbers I gave were from the Yamaha 2001 catalog: F100=358lb, F115=416lb, on the assumption (obviously wrong) that the Mercurys would weigh about the same, as they use the same powerheads.

Why would the Merc 4s 90 weigh 30lb. more than the Yamaha F90/F100 (same powerhead), yet the Mercury EFI 115 weigh 30 lb less than the Yamaha F115 (same powerhead)?

As I said, I don't believe it. But, there are lots of things that "everybody knows" that I don't believe. :)

Red sky at night. . .
JB

Jarhead posted 07-20-2003 08:34 PM ET (US)     Profile for Jarhead  Send Email to Jarhead     
Good point there JB and I don't have the answer. :)
dogfish2 posted 07-21-2003 12:32 AM ET (US)     Profile for dogfish2  Send Email to dogfish2     
My question is why would MERC list a specific weight for a motor and have that figure be inaccurate? Misleading the consumer would only serve to discredit the company and eventually lose business. I was told by MERC company reps and a trustworthy dealer that 4 stroke, 75hp, 90hp and 115hp were the same weight. Perhaps JB is right, as there may be hidden pounds (oil, gearcase oil, prop, etc). Personally, I believe that a company has too much reputation and credibility to lose by posting mis-information. Anyway, with the technology and research time put into all these new motors, it would be pretty difficult to go wrong. It comes down to personal perference.
MnFast posted 07-21-2003 09:07 AM ET (US)     Profile for MnFast  Send Email to MnFast     
Indeed my original question has spurred an interesting debate on 4's versus 2's and I appreciate all of the input. Dogfish2 said he had a 90 4-stroke delivered on his Montauk, but I assume that he has a more modern Montauk (perhaps the 170) and the length is slightly longer, the beam is wider to accommodate the new hull design and specs show that the swamped capacity (god forbid)has increased by 1400 lbs (thought the passenger capacity remains the same as does the dry weight). This morning I am heading into my (not so local - due to price)dealer to purchase a Yamaha 90 4 cycle unless someone or something disways me and after I bolt it on and take her for a spin, I will report my findings. Cheers all.
dogfish2 posted 07-21-2003 09:29 AM ET (US)     Profile for dogfish2  Send Email to dogfish2     
Good luck with your new purchase. I"m sure that you"ll be very pleased. My Montauk is a 2000 yr. model, so it is not the new 170. My fishing buddy has a 90 Yam 4s and is quite happy with the performance. Safe boating!
Bigshot posted 07-21-2003 10:39 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Enjoy your new engine....you can still use your old controls, etc on a new Johnson by the way.
ratherwhalering posted 07-21-2003 12:44 PM ET (US)     Profile for ratherwhalering  Send Email to ratherwhalering     
You will need to purchase and install a new wiring harness, as there is no adapter to convert your old wiring harness. Bigshot is correct, your instruments will all work with the new engine, however you will need to purchase and install a "system check" gauge, or a new tachometer with the integrated "system check" already installed. I have an '87 Montauk, and when the 1987 '90 Johnson dies, (if ever!) it will be replaced with the 70hp Johnson 4-stroke, or the 90hp Johnson e-tech, should that engine ever see the light of day (due out in October now, I believe.)
Bigshot posted 07-21-2003 01:29 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Wiring harness still works, you need to buy $35 adapter.
lhg posted 07-21-2003 02:10 PM ET (US)     Profile for lhg    
Yamaha for 2003 has "corrected" the weight of the 90 4-stroke to 370#. Merc 115 EFI is 386, but Yamaha's version is 402# because it has the large V-6 gearcase on it. For 16 lbs difference, the Merc 115 is a no brainer. I would not get a carbed 4-stroke these days. Everything is going EFI.

Boston Whaler sold many Classic Montauks factory rigged with the Merc 90 4-stroke. But for the 386# weight, I would get the 115 EFI. Suzuki's 2003 catalog does not show the weights of their engines.

Perry posted 07-21-2003 02:48 PM ET (US)     Profile for Perry  Send Email to Perry     
Just out of curiosity, how is it that the carbed Mercury 90 and 75 hp 4 strokes weigh the same (386lbs) as the 115 EFI 4 stroke? Don't the associated EFI parts weigh more?
lhg posted 07-21-2003 09:53 PM ET (US)     Profile for lhg    
Evidently not. Until Mercury upgraded to a big automotive style 60 amp belt driven alternator on the 150 and 200HP EFI 2 strokes, the carbureted and EFI models weighed the same at (406 lbs).

Also, the Mercury built Yamaha carbed 4-stroke F-60 and the Mercury 60HP EFI 4-stroke each weigh 248 lbs.

The idea that EFI adds weight is simply not correct.

elmofudd posted 07-21-2003 11:07 PM ET (US)     Profile for elmofudd  Send Email to elmofudd     
i had a 96 montauk with a 96 90hp honda i think it was to heavy for the boat.also had a 97 alumaweld with a 75hp merc i'll tell you the alumaweld would run circles around the montauk.might be apples and ornges.but would go with bigshot get the 70johnson 4stroke its lighter
MnFast posted 07-21-2003 11:47 PM ET (US)     Profile for MnFast  Send Email to MnFast     
Well folks, I bought the 90 Yamaha 4 stroke, carburated 3 cylinder, double overhead cam outboard today, with new wiring harness, new combo tack/trim gauge, but the binnacle had not arrived yet, so I haven't gotten it wet yet. Looks pretty nice, though. To be continued.....
lhg posted 07-21-2003 11:59 PM ET (US)     Profile for lhg    
That would be a 4 cylinder, 97 cubic inch displacement. Weight 370#.
bsmotril posted 07-22-2003 03:11 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
2s torque vs 4s torque for JBCornwell.
JB, what you said earlier about torque and HP applies true only at a given RPM. Max rated Hp is coming in at MAX RPM, so you are right at that single point in the torque curve about 2s and 4s equality. But who runs WOT all the time ? Where 2 strokes have the advantage over 4s is delivering greater torque lower down in the RPM range. This is what directly translates to the better holeshot and the ability to hold a heavy boat on plane at lower rpm without the rpms bogging down and the boat plowing.

The answer to your other question reg the weight difference in Mercs versus yamahas is because of:
Different clamp/mount brackets
Different exhaust tuners with Mercs having longer "pipes" for more midrange torque
And, I believe, one uses an injected molded cowl versus heavier fiberglass cowl.
BillS

MnFast posted 07-29-2003 12:29 AM ET (US)     Profile for MnFast  Send Email to MnFast     
I have about 7 hours of break in time on the new Yammi 90 and I must report that I am quite pleased. My orginal concern with too much weight was unwarranted. While it might be heavier than the old Evinrude V-4 90, the boat can handle the weight well. Bolt holes in transom line up perfectly.
The provider of the engine offered to rig it for only $100. I couldn't refuse. I knew (and told him) that the job was bigger than that, but he held to his word.
I got the digital read out from Yamaha which provides rpm's, trim indicator, engine hours and speed as well as info such as overheat, etc. should that arise (no pun intended).
Performance? Well, I am quite pleased. Only recently have I been able to put the hammer down (and only for short times) due to break in requirements, but speed is at least as good as the old V-4. Tonight on flat water, alone (but with two batteries on board) I was doing between 42 and 45 mph. I think exceleration is quite impressive, but really haven't hammered it from dead stop as I do not want to beat it up during break in period. It came with a 17 pitch prop, but instead put on a 15 for the fun factor and the dealer thought a 17 would have too many rpm's. So far it is a good choice. Aluminum props are very reasonable and I guess they recommend the Yamaha props over after market props. The price is reasonable enough from Yamaha to believe it. I am not ready to pop for a SS prop yet.
So, I hope this info is helpful to someone who had a similar question as mine. Thanks for all the input.

Perry posted 07-29-2003 02:07 AM ET (US)     Profile for Perry  Send Email to Perry     
Sounds like a good set up. By the way, a 17 pitch prop will turn LESS rpm than the 15 pitch.
jackpot posted 08-04-2003 02:17 PM ET (US)     Profile for jackpot  Send Email to jackpot     
Mn - I just bought the same engine for my '89 Montauk and the engine w/ Yamaha 15 pitch prop was trying to redline about 6200. At 6000 RPMs mine would only do about 35mph. I have exchanged 15 pitch for a 17 and will take it out this weekend. The Yamaha 4-stroke 90 hp is a great motor and w/ 15 pitch prop, has plenty of pull. We'll see how 17 pitch does. Thanks for asking this question. I have learned a lot from all of the discussion.
MnFast posted 08-07-2003 12:46 AM ET (US)     Profile for MnFast  Send Email to MnFast     
Jackpot-
I am interested in hearing how the 17 pitch prop works for you in comparison to the 15. I need to buy a 2nd prop and your input might have bearing on my decision. Thanks.
Andy Montauk posted 08-17-2003 06:45 AM ET (US)     Profile for Andy Montauk  Send Email to Andy Montauk     
Hi Mn & Jackpot:

I've got a 1976 Montauk that I need to repower, and I've been looking at the 90hp Yamaha 4 stroke. My main concern is weight. Did your new Yammies affect your boat's trim?
Also, how do you like the new motors now that you've had them for awhile?
I really enjoyed this forum. Any thoughts or suggestions would be appreciated.

Andy

MnFast posted 12-29-2003 10:20 AM ET (US)     Profile for MnFast  Send Email to MnFast     
I have not been on in a while, but now that the season is well behind me (I live in the northland) my Whaler with its new Yamaha 90 has been put to bed. I think I got somewhere around 30 hours on it since I purchased the new Yamaha.
I must report that the motor has performed well. I was concerned about performance both on the top end and out of the hole in comparison to the Evinrude 2 cycle 90 that I had before. First of all the Yamaha runs smoother, much, much quieter and doesn't smoke. It was nice to be able to remove the oil bottle for the V-4.
The Yamaha weighs more, but that did not affect the trim under power. I suppose the boat sits a little heavier aft while still in the water (at a dock), but I am 220 lbs and standing at the outboard, there is no concern.
I think the boat runs out of the hole as fast, if not faster than the previous motor. On the top end, it is about the same between 40 and 45 mph depending on if I have a second battery in for a trolling motor (big deep cycle) and if I am running alone.
Fuel consumption is tremendously better. I don't go through nearly as much fuel as I did with the older motor.
She starts very quickly. One need not advance the throttle to start her (and that is not recommended). Turn the key and she is humming away.
So, I am very please with my purchase.

Post New Topic  Post Reply
Hop to:


Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.