170cc Repower

Alex621

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I am considering a repower for my 2006 170cc. I currently have a 06 Yamaha f60 on it. Has anyone re-powered from the f60 up to the newer f70 and can comment on the tangible difference (or not) in power and performance? I think the only other engine I would consider would be the Honda 60, but imagine the Yamaha 70 at the same weight but 10 more hp might be hard to beat. This whole repower idea is a little frivolous because there’s nothing really wrong with my old motor besides it age, but my son is fully grown now and I definitely notice that the 60 struggles a little trying to pull him on a tube.
 
A friend of mine has a small Boston Whaler. He re-powered his old 90 Yamaha 4 stroke to the new 90 Yamaha. The old one was probably 15 or 20 years old and nothing wrong with it, just old. The new one is world's better. I would imagine going from the old 60 to the new 70 would be a similarly huge improvement.
 
If the original engine still has good compression on all three cylinders then option B is reduce the drag of "any" engine's lower unit by installing one of these:

https://thmarinesupplies.com/products/atlas-micro-jacker-small-outboard-hydraulic-jack

And quite sure that is much less expensive than an entire new engine.

The F70 though is a fine engine (loved my last one) and I would always (even the present one) advise to install one of these...


Hope this helps!
Dave
 
I have a 2008 170CC and repowered in 2018 to the Suzuki 70 HP 4 stroke. I am extremely happy with this motor. You literally can not hear it at idle and at take off the thrust is unbelievable. With 2 people I can cruise about 37mph. I’m not sure about Yamaha, but the Suzuki comes with a 6 year factory warranty.
 
Going to a prop with less pitch and/or installing an outboard hydrofoil like a Doel-fin is another option.



 
I have a 08 170CC with a 2009 Suzy DF70A (155kg). Not a single issue so far, I can glide at 36MPH and this is the quietest engine i have EVER experienced at idle. When I push her from stop, you'd better hold on. I seem to be able to get on plane around 3500rpm. I average 2.5 LPH trolling and average 4.5 LPH cruising and pushing her hard. On a side note, it has a self adjusting timing chain, so no more belt to worry about. Best engine by far I have ever owned. Im from the Pacific Northwest and all the tour and charters seemed to have switched to Suzy's. My 2 cents
 
I guess LPH is liters/hour? So you are using just over 1 gallon/hour cruising speed? How fast are you going at cruising speed? Trying to equate your numbers to miles/gallon, but it sounds like very, very good fuel economy.
 
I will piggyback on Pilotman! I absolutely agree with his comments. Suzuki is giving Yamaha a run for its money with their outboards today. I am on the east coast in Maryland and I have seen a huge increase in people switching over to Suzuki. I would highly suggest to at least research them before pulling the trigger. As stated previously the performance is remarkable. My first day out on the water with my new Suzuki I was floored how little fuel I used and still use today. It is a strong motor and performance remarkably well.
 
Funny, since my original post I have really backed off the idea of dropping big money on a new motor and have swayed back to the ride it till it dies mentality. In my research I see a lot of people advocating for Suzuki’s. The biggest selling points being an equally great motor for significantly less money and a longer warranty. The bonus to the Yamaha was the 10 extra HP at the same weight as the 60 HP motors and 100 less pounds than the competitive 70’s and 75.
I have pretty much decided to give a hydrofoil or Nauticus Smart Tabs a try. Seems like people on these forums can go either way and they are both good performers. Sounds like the debate could go on and on. A matter of preference?
Putershark- thanks for the links, but what does the hydraulic jack do? I looked at the link but I didn’t really understand what one of those would do for me. Especially since they are pretty pricey. Thanks
 
I guess LPH is liters/hour? So you are using just over 1 gallon/hour cruising speed? How fast are you going at cruising speed? Trying to equate your numbers to miles/gallon, but it sounds like very, very good fuel economy.

Yes litres per hour. Trolling i go 1.5-2knots but my 2.5LPH also includes full throttle to and from my fishing grounds approx 30mins round trip. If we cruising, we cruise at 15-20knots and at an average 3.5LPH so yes just under a gallon per hour. These engines sip fuel and because of that i have no friends that want to do day trips because their boats use to much fuel. I go everywhere i can with my wife and explore while my fishing buddies stay close to home. I have an 80L tank which lasts 3 full 8hr days with trolling which includes full throttle there and back and still have a quarter tank. Hope this helps.
 
Going to a prop with less pitch and/or installing an outboard hydrofoil like a Doel-fin is another option.




This is by far the best and cheapest option if your looking for that extra little boost. The debate over engines has gone on for ages so in the future do your research and you'll be rewarded with a problem free experience. Good luck and keep us posted with what you choose and how it worked out. Nothing worse than a thread that leads to nowhere.
 
I know nothing about the Nauticus smart tabs, so can't help you there. My experience with the Doel-fin is that it may well be the best bang for the buck there is, especially since it only costs about $30 and you can be install it yourself in a half hour. The only real potential drawback is you have to drill 4 - 1/4" holes in your cavitation plate. I could easily see not wanting to do that on a new motor, but on a 10-15 year old motor, that's not such a big deal.
What will it do? Get you on plane quicker, smooth out the ride, allow you to run on plane at a slower speed and reduce or eliminate porpoising are all potential benefits.
I originally bought one in the 1980s for a 13 foot whaler that porpoised badly and constantly in the chop running across the Chesapeake Bay. Put on the Doel-fin and that stopped instantly. Have since had some form of hyrdofoil on virtually every small outboard I've owned (30 years and 5 boats - 13 whaler, 17 wellcraft, 20 mako, 20 wellcraft, 15 logic). Now i use a slow troller because I get both the planing benefits of a traditional hydrofoil and the reduced trolling speeds when I want that.
Benefits vary according to hull style with the porpoising being very beneficial on flatter bottomed boats and the quicker plane/ability to run on plane at a slower speed more helpful on a v hull.
With your described issue, I'd use a Doel-fin or something similar in a heartbeat. but like I said, I know nothing about the Nauticus smart tabs, so can't offer any comparison there.
Also, keep in mind the right pitch prop can make a world of difference. Would be extremely helpful if you could find a way to have someone let you borrow a prop long enough to try out different pitches. or get advice from someone with the same boat/motor combination.
 
Yes litres per hour. Trolling i go 1.5-2knots but my 2.5LPH also includes full throttle to and from my fishing grounds approx 30mins round trip. If we cruising, we cruise at 15-20knots and at an average 3.5LPH so yes just under a gallon per hour. These engines sip fuel and because of that i have no friends that want to do day trips because their boats use to much fuel. I go everywhere i can with my wife and explore while my fishing buddies stay close to home. I have an 80L tank which lasts 3 full 8hr days with trolling which includes full throttle there and back and still have a quarter tank. Hope this helps.
WOW!!!
That's something like 15-20 mpg at cruising speed! That's incredible. I know my old 15 Logic and my current 17 Triumph both get very good fuel economy, but I don't think it is that good.
 
WOW!!!
That's something like 15-20 mpg at cruising speed! That's incredible. I know my old 15 Logic and my current 17 Triumph both get very good fuel economy, but I don't think it is that good.

I don't know how to convert the numbers so I'll assume there're right lol. I'll add that if i remember correctly, cruising is 4000-4500rpm. I keep the boat very light and only have two people on board combined weight of 290lbs. I get her on plane and trim her up then readjust throttle until she's just right. This is also on days where the wind is under 10knots so no white caps. Oh and it's on mid grade marked fuel
 
I don't know how to convert the numbers so I'll assume there're right lol. I'll add that if i remember correctly, cruising is 4000-4500rpm. I keep the boat very light and only have two people on board combined weight of 290lbs. I get her on plane and trim her up then readjust throttle until she's just right. This is also on days where the wind is under 10knots so no white caps. Oh and its on mid grade marked fuel
 
Hey one last thing, my original post is 4.5LPH then it changed to 3.5. 3.5 is my overall average (brain fart). Crusing is 4.5LPH. Just wanted to correct that.
Yes litres per hour. Trolling i go 1.5-2knots but my 2.5LPH also includes full throttle to and from my fishing grounds approx 30mins round trip. If we cruising, we cruise at 15-20knots and at an average 3.5LPH so yes just under a gallon per hour. These engines sip fuel and because of that i have no friends that want to do day trips because their boats use to much fuel. I go everywhere i can with my wife and explore while my fishing buddies stay close to home. I have an 80L tank which lasts 3 full 8hr days with trolling which includes full throttle there and back and still have a quarter tank. Hope this helps.

My original post is 4.5LPH then it changed to 3.5. 3.5 is my overall average (brain fart). Crusing is 4.5LPH. Just wanted to correct that.
 
4.5 liters is 1.2 gallons. So you are burning 1.2 gallons when going 15 to 20 knots. A knot is 1.15 miles, so 15-20 knots is 17.25 to 23 miles, averages to about 20 miles. 20 divided by 1.2 = 16.67 mpg.

So if you are burning 4.5 liters and going 15-20 knots, you are getting about 16.67 mpg.

That is incredible, on any boat, in any sea conditions.
 
Doel-Fin is the right place to start. Just MY opinion (from experience).
 
Not a fan of the plastic ones since they can flex.

 
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