Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Re-power 1977 Montauk 17
Posted by kena on 07/12/17 - 7:12 AM
#1
I recently bought a 1977 Montauk 17 that I love. It was re-powered with a 1998 Mercury 115 HP 2 stroke by the previous owner. In addition to heavy fuel consumption I'm finding the weight of this engine(approx. 360 lbs.) keeps the stern lower than I'd like it to be. I am researching now to possibly re-power with a 4 stroke lighter smaller HP engine.
My usage is 90% my wife and I cruising around Narragansett Bay and some occasional fishing, so I don't need a lot of speed or power.
My local Mercury dealer suggested a 75 HP but the weight is as much as the existing 2 stroke 115 HP on the boat now.
I am thinking about a Merc 60 HP 4 stroke which would save about 100 lbs. over the 75 HP, but I don't want to under power the boat either.
I am interested to hear what other members think about going to this engine.
Posted by cfelle2 on 07/12/17 - 7:50 AM
#2
I have a 1999 Mercury 50hp on my 1976 Montauk and it runs very well with my wife and myself. I think the lighter outboards in the 250 lb range work really well with this boat. Another outboard to consider is the Yamaha F70. It weights 257 lbs and is the Yamaha alternative to the Mercury 60. I have no preference to either make I just thought I would suggest another option to consider.
Good Luck
Chris
Posted by EJO on 07/12/17 - 9:48 AM
#3
Look at a standard 90HP E-Tech 320 LBS I think the 60 Merc EPI is a great engine but it will be underpowered on your 17' boat. I know your not looking for speed but it is nice to get on to plane in less than 20 plus seconds.
Posted by Phil T on 07/12/17 - 10:34 AM
#4
In addition to the E-TEC 90, the Yamaha F70 is a popular choice. Expect WOT to be 37-40 mph mounted 3 holes up with a good stainless prop.
Posted by DennisVollrath on 07/12/17 - 10:38 AM
#5
Hi Kena,
With the right prop a 60hp will likely be fine. You are trading off time to plane against top end and some fuel economy. I have no experience with the Merc 60, but did run a Yamaha F70 on a 1988 Montauk 17 which I used to own. It popped up on plane nicely even with 4 people, but obviously not as quickly as when solo. Top speed was about 36mph, and I was slightly underpropped when lightly loaded.
The F70 was(is?) built on the same block as the F60, but had a higher top RPM limit. I suspect this is where the extra 10 hp comes from. If so, I would think the low end torque curves between the two motors would be close and their time to plane would be close as well. If the Merc 60 is similar I think you'd have enough pop with the right prop, but just give up a few mph of top end. Perhaps you might save some rigging expense by staying with Mercury as well.
Good luck with your decision.
Dennis
Posted by kena on 07/12/17 - 2:28 PM
#6
Thanks to all for the great input! I have already priced the Merc 60 HP with a local reputable dealer that has serviced my 115 HP.
Based on your suggestions I am going to research the Yamaha F70 and compare.
Thanks again to all.
Posted by JRP on 07/12/17 - 2:59 PM
#7
Another vote for the Yamaha F70. You will knock a lot of weight off the stern, and still have very decent power. Plus you will be running a modern 4-stroke, which is good for re-sale.
Let us know what you decide.
Posted by kena on 07/14/17 - 1:52 PM
#8
Today I purchased the Merc 60 HP EFI four stroke with the Command Thrust gear case. My reasons are various but after comparing with the F70 it mainly came down to a trust and familiarity with my local Merc dealer. They had the 60 in stock and I am dropping the boat off tomorrow and will have it back in the water next week.
From what I could tell the Command Thrust 60 and the F70 are very similar in performance. Getting the CT gear case alleviated some of my low power fears when getting up on plane. The Merc was less money but not by much and I am able to re-use some of my existing controls.
I will provide an update once I have a chance to run with the new engine.
Thanks again for your input.
Ken
Posted by Phil T on 07/14/17 - 2:01 PM
#9
You want to force the dealer to install the engine
at least 2 holes up
Read this:
http://www.whalercentral.com/articles...cle_id=106
You also want a stainless steel prop.
Rigged and propped correctly, I would expect a wide open throttle (WOT) speed of 32-35 mph running with just you and no gear.
Posted by kena on 07/14/17 - 7:16 PM
#10
Thanks Phil
I will make sure they do that
Posted by Mambo Minnow on 07/16/17 - 10:43 AM
#11
Check out the brand new 2017 Yamaha 90 HP four stroke. I think they finally got the weight down to where it is a practical alternative to the much touted E-tec 90 2 Stroke DFI.
Posted by JRP on 07/16/17 - 12:02 PM
#12
Mambo Minnow wrote:
Check out the brand new 2017 Yamaha 90 HP four stroke. I think they finally got the weight down to where it is a practical alternative to the much touted E-tec 90 2 Stroke DFI.
It's nice that Yamaha got the weight down some more on those engines, but they are late to the party. Merc has offered 4-strokes at the same HP and weight (but higher displacement) for several years now. Merc even offers versions up to 115 HP at the same weight!
Yet, even at those weights, he would not be getting much or any weight off the transom. That's why that lightweight Yamaha 70 is so attractive (as is the Merc 60 he purchased) -- it drops about 100 lbs off the stern!
Edited by JRP on 07/16/17 - 12:03 PM
Posted by EJO on 07/17/17 - 11:52 AM
#13
I still say the F70 would have been a better choice and I have the Merc 60 and love it but feel it is under powered on a 17' Montauk.
Hey I feel the 60 is under powered on my 2008 Montauk 150 which from what I understand weighs the same as the old Montauk 17.
Posted by kena on 08/04/17 - 12:25 PM
#14
I thought I'd give a quick update on my results with the new Merc 60HP Command Thrust.
After testing a couple of different props, I settled on a stainless Vengeance with a 14 pitch. I noticed a significant power increase with this prop over a similar aluminum one that I tested. I know there were some skeptics on going with this engine choice but after 3 separate days in varying conditions my experience has been nothing but positive.
WOT is around 5500 RPM and 32 MPH. I am up on plane within a few seconds. This is with my wife and I, standard equipment on board and 15 gallons of fuel.
As I had mentioned previously where I am running I very seldom can run any higher than 25 MPH due to chop etc so the top end is fine for me.
Just thought I'd share my results for anyone else who is evaluating re-powers and has similar needs.
Thanks again to all for your input.
Ken A
Posted by Warmingst on 01/30/18 - 3:13 PM
#15
kena wrote:
I thought I'd give a quick update on my results with the new Merc 60HP Command Thrust.
After testing a couple of different props, I settled on a stainless Vengeance with a 14 pitch. I noticed a significant power increase with this prop over a similar aluminum one that I tested. I know there were some skeptics on going with this engine choice but after 3 separate days in varying conditions my experience has been nothing but positive.
WOT is around 5500 RPM and 32 MPH. I am up on plane within a few seconds. This is with my wife and I, standard equipment on board and 15 gallons of fuel.
As I had mentioned previously where I am running I very seldom can run any higher than 25 MPH due to chop etc so the top end is fine for me.
Just thought I'd share my results for anyone else who is evaluating re-powers and has similar needs.
Thanks again to all for your input.
Ken A
I am in the exact same situation you were in. I just bought my first Montauk after selling my 11ft SS. The only problem is it needs a new engine. Marina suggested the 90 Mercury, but in my opinion ITS TO HEAVY for my boat and the boat already sits a little low with the current engine. So now I am starting to consider a new 60hp Mercury, or a 60 Evinrude. I fear that I wouldn’t be able to have 3-4 people in the boat, which is one of the reasons I sold my 11. Have you been out in your boat with 3-4 people and if so how did the boy perform. -stephen
Posted by kena on 01/31/18 - 9:33 AM
#16
Stephen
I used my boat several times with four adults and had absolutely no power or speed concerns. I think that the Command Thrust feature on the engine along with my prop choice were big factors. I know that several people thought this was under powered but for my use it works great!
My engine well drains are now above the waterline and I still have my battery located in the stern. It sips fuel and is really quiet.
If you do decide to go with the new Merc I would definitely include their SmartTach digital unit. It is a great source for running info, fuel, battery charge etc.
Good luck with your choice!
Ken A
Posted by enggass on 01/31/18 - 1:05 PM
#18
I have a 1989 Montauk that I picked up with original Merc 90Hp. What holes should that be mounted in?
UPDATE:So. Just checked. It is mounted one hole up. Aluminum prop. Pros? Cons? I’m new to this. Any insight appreciated. Thanks.
Edited by enggass on 01/31/18 - 4:17 PM