What size engine and type?

[mason23]

Hi everyone,

My current 1978 140hp Merc outboard has finally had its day. So I'm looking at a new engine for my 5.2m Caribbean (fibreglass) Cougar, modified from ski boat to fishing boat. I've been out looking at a few engines in the 90 to 115hp range, but because of the massive changes in tech, I'm not sure what would be an ideal engine size and type for my boat. I realise I'm opening up a can of worms in the 2 stroke vs 4 stroke debate, but it would be nice to hear some tried and tested opinions on what people use now. More importantly I'm thinking 115hp will allow me to go offshore in calm conditions (remember its a modified ski boat), but will 75hp get me there too??? Usually I just troll the estuaries but would love to get out every once in a while when the conditions permit.

Any advice would be much appreciated. Cheers in advance

[Chimo]

Hi Mason

Dont know what sort of hrs you do but IMHO 4 st seem to cost too much more to buy and to service and do not think there is any chance of a beneficial cost benefit ratio from a 4 unless you do heaps of hrs.

Also might I suggest you consider who is to service the new motor. If you have a reliable good person I think I'd go with the brand he services.

The above being said in 2s Etecs the 75 and 90 is the same block therefore the same weight. The 115 V4 is the only 4 cylinder Bombardier make and my service tech reckons the sun shines out of them! I have the older carb Ocean Pros and its hard to come up with any reason to quit them as they only have 400hrs.

Have you considered a second hand 115 either carb or the earlier DI in the BRP? Again depends on the service person and relationship you have?

On the other hand you could always get another boat with the excuse you have or you will end up with an old boat with a new (ish ) motor and still probably won't have what you really want anyway?

Sorry mate no such thing as a simple yes or no in our sport, its a bit like trailers, some say no side rollers but must have side skids with tinnys but the other side of the story is what about having enough rollers to support the weight properly! Not too disimilar to you fishing outside and coping a greeny over the front. I did it once in my old ski boat converted to fishing before I said once is too often!

Good luck whatever way you go

Cheers
Chimo

[death_ship]

115 4 stroke only option, you will get your extra money back at resale. she will do 35 knots easy.

[myde]

I agree with Chimo on his post. Firstly, the importance of having someone you trust and who will listen to you is very important, maybe even more important than motor brand or type.

Secondly the 115 Etec is a brilliant motor. We repowered in April from a Yammie 115 to the Etec and couldn't be happier. We get instant starts even on the coldest winter morning with air and water temps around 14 degrees. The Etec also trolls brilliantly, only using about 1 litre of fuel per hour at 4-5 knots.

Hope this helps.

Regards,

M.

[FNQCairns]

I don't know your hull but being a ski boat it would be low deadrise, I guess a 75 carb merc would push it, as you say you normally just troll and I suspect not real worried about how fast you get to where you are going, but how slow is too slow for you?? and for how long?. The modern engines are no more and possibly on average (2st V 2st) less powerful than the carb and efi engines of old HP for HP, but not ones as old as your engine.

You could probably find a good late model used 4cyl engine for 6k something like the yam 115 or a johnson/evinrude 115, even another merc. All of the later model 115 2st will all feel as or near as powerfull as the one you are replacing and be better on fuel.

A large capacity 90hp 4st (like the suzuki) will push it OK but you will pay for it.

IMO 6K purchase price V up to 14K to do the same thing - there is no comparison based on price, but the new tech 2st and the 4st will both give you a MUCH nicer troll but it's a lot extra to pay, they will also be better on fuel HP V HP but still....

cheers fnq

[mason23]

Thanks very much to Chimo, Myde, FNQ and Death_Ship,

I've had a look in the past 2 days at a Mercury Optimax 2st and a Suzuki 4st. The latter is very pricy at 115hp, around 13800!!! I can pick up the Merc in 115hp for around 12k fitted.

Still not sure on the benefits of 4st over 2st, some people say the 4st is more fuel efficient while I've heard that the latest tech in 2st is pretty much even par in this category...go figure. Some say the 4st is quieter, although every 2 st guy I've heard from says the difference between both engines is hardly noticeable. So then, reliability, servicing, and overall performance??? I have to admit, I'm leaning towards the merc optimax from what I've heard but I want to make the right decision based on as much as I can learn, that way no regrets cause its such an important decision.

Thanks guys

[BM]

Mason,

Weight is the most concerning factor for you to consider. Many owners of older boats who are repowering with new/newer engines are running into trouble with engines that are too heavy.

You want to replace your engine with one of very similar weight. If you dropped a 4 stroke on it you will most probably sell the boat because the water coming into the splashwell constantly will annoy you along with the bow up attitude of the boat everywhere you go.

SO, hunt for an engine based on weight the same or very similar to your 140 "tower of power". I can't stress it enough.

Cheers