Suzuki DF100b or ???

[Mr Flibble]

As it’s Friday.
New outboard time.
Anyone running a Suzuki DF100b on a 5.5m RIB?
I’ve a Humber Ocean Pro 5.5m. Transom rated to max 200kg and 115hp.
Currently has a Tohatsu 115 tldi on the back.
Usually out with 2-4 on board or 2-4 divers + cox.
Not overly concerned with massive top end speed, would be happy with 35mph with 3-4 on board, obviously a bit less with dive kit.

Been given quotes for the following;
Suzuki DF100b - 158kg, 1500cc
Suzuki DF115b - 190kg, 2000cc
Mercury F115 Command Thrust - 165kg, 2100cc
Tohatsu MFS115 - 178kg, 1800cc

Of those listed the Suzuki DF100b is by far the least expensive. Would probably also be the most frugal on fuel (another consideration). I just have a concern that the 1500cc block is relatively small. Would the engine be revving its head off and working very hard to get up and go and maintain a decent cruise speed?

The Mercury ticks a lot of boxes with a big block and light weight but it’s by far the most expensive one listed.
The Suzuki DF115b is £1100 cheaper than the Mercury and it has some nice features (drive by wire etc). Almost placed an order the other day but got a nagging doubt about the weight as it is near the max rating. I’m hoping to fit a 5hp backup at some point which will add a further 25kg.
The Tohatsu looks a nice engine but belt driven, I’d prefer a chain driven cam and parts availability might be an issue.

Obviously gear ratio/prop selection would have an effect but is anyone running a Suzuki DF100b on a 5.5m with a few on board? Does it have enough oomph or does it work hard to get going with the small engine block?

Any opinions greatly received.

[Davie]

Yamaha VF90LA 1800cc 160kg

Sent you a text

[beerbelly]

i have a 115 comand thrust on my 5.5 destroyer and with a 4 blade spitfire prop its very well matched tops out at a little over 36 knots but the low range and mid rpm pick up is great i even have enough reserve capacity on the transom for a little 3.5 back up . its very good on fuel and very quiet and smooth i would recommend one

[willk]

Originally Posted by Mr Flibble

The Mercury ticks a lot of boxes with a big block and light weight but it’s by far the most expensive one listed.

You are running moderate to high weight loads - 4 PAX or 4 Divers plus gear.

I agree that the extra CC will likely make itself useful getting those porky divers out of the hole. The weight of the merc is surprisingly (to me) low.

IMO, time to check down the back of the sofa...

[Pikey Dave]

There is no replacement for displacement.

[jeffstevens763@g]

I had a 90 on a 5.5 plenty of power 4 up with kit and fuel never had to go flat out great engines IMO

[Mr Flibble]

Thanks for all the helpful advice so far. Really appreciate people taking time to help.
Was out diving last night (shore not boat) and decided to weigh my dive kit as I was loading up the car. 12 litre twin set with wing, regulators and umbilical torch is 50kg, 11 litre stage Deco bottle 20kg, lead weights etc another 10kg. So 80kg for my standard boat rig, another 20kg if doing multi stage Deco. So dive kit for 1 diver is approx 80-100kg, equiv to one big hefty person. So 2 divers equates to 4 non divers, 3 to 6 etc.
That's a load in itself.
Think the df100 would be great for runs out with myself, her indoors and the pooch but when 2-3 divers as well in any kind of lumpy sea it will struggle.
I feel an order going to the good folk in Wisconsin in the next few days. ��

[willk]

Originally Posted by willk

... getting those porky divers out of the hole....

Yer welcome!

[jonp]

I tested a new Suzuki 100 a couple of weeks ago on a new 14ft centre console, the same boat as I already have, only mine has a 90 honda and Im looking to re-power. The Suzuki was considerably quicker and far better on fuel than my Honda, to the point the Suzuki was returning 4km per litre at 60kh. My Honda returns 1.6km per litre.

Having owned a Suzuki 140-115 and 90 I decided on a Yam F115 for my 14.5ft console.

[Iankristy]

Originally Posted by jonp

I tested a new Suzuki 100 a couple of weeks ago on a new 14ft centre console, the same boat as I already have, only mine has a 90 honda and Im looking to re-power. The Suzuki was considerably quicker and far better on fuel than my Honda, to the point the Suzuki was returning 4km per litre at 60kh. My Honda returns 1.6km per litre.



Having owned a Suzuki 140-115 and 90 I decided on a Yam F115 for my 14.5ft console.

Is it me or your post sounds like ‘I have a Honda, Suzuki was brilliant so I bought a yam’ 🤷🤣

[jonp]

Originally Posted by Iankristy

Is it me or your post sounds like ‘I have a Honda, Suzuki was brilliant so I bought a yam’ 🤷🤣

Well I didn't really want to divulge my reasons for not wanting another Suzuki as I didn't want all the hassle. I wouldn't choose a new boat with them but have bought secondhand boats with them.

Suzuki (three Ive owned oldest being 2014) were not brilliant by a long shot. The 140 had an issues where at times the engine would not go over 3000rpm, which made it extremely dangerous where I head from. For bar crossings boats need to have plenty of power that can be relied on to get through the rough conditions as quickly and safely as possible. The trim also failed on the 140 and 90. Gear issues in the Suzuki 90. All of those issues are common over here where we have a huge boating community compared to the UK. I boat from a place that has the east coast of Australia most dangerous bar crossing.

The Suzuki engines are known to have corrosion issues, which is another reason I would prefer not to have another, all three of mine had issues.

Yes I own a small 14.5ft boat with a Honda 90, which I find to also be lacking the power needed for bar crossings (yes it reaches 6100rpm). Its also heavy on fuel. I also skipper a commercial 6m abalone and urchin boat which was powered by a 250hp Honda until a few weeks ago. Again reliable but very sluggish compared to the 250 Yamaha it replaced after 3yrs.

Our marine rescue vessels both have twin Suzukis which have had their fair share of issues
Our local maritime patrol vessels also run twin Suzukis and get replaced with quite low hours.

So do I think Yamaha are more reliable ? well in 46yrs of boat owning Ive still to have a breakdown where Ive needed assistance at sea and mostly used Yamaha. For me its more the resale value of Yamaha that make them a better engine to purchase. Also one of the boats I skipper is owned by a Yamaha mechanic who does my services for next to nothing and he rates them as most reliable.

Most of my fishing is beyond phone and radio range, often I will head offshore for two weeks at a time. Im on the water most days in either my own boat or others powered by outboards both recreationally or commercially. I also have a Zodiac powered by mercury which is proving ok, though very harsh compared to the other brands.

[tehguy]

We have twin Suzuki DF90A from 2011, ~700 hours on both, flushed with fresh water after every use, out of water when moored, serviced every year. We've had to replace an ECU on one and a fuel pump on the other. No other major issues.

[Libertas]

HI, I realise this was posted 12 months ago and may no longer be relevant, but I have a DF100B, not on a RIB but on a 5.5metre 700kg (dry) warrior 170 and am happy to tell you about its performance if useful. No worries if not.

[Pikey Dave]

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