mate i highly recomend yamaha fourstroke i have twin 150 fourstroke yams done 1120hrs still start / run like new plus good economy but i think u probley cant go to far wrong with any brand these days fourstroke or 2

Don't get a mecury 4 stroke, they are gutless as and very sesitive to the throttle.

 Yamaha, Suzuki or Honda for the 4 stokes or a E-Tec for the EFi 2 Strokes.

 It was recommended to me that for anything under 150hp go the 2 strokes, above that hit the 4 stokes for the cc capacity to give the kick up the bum

i had an 80 yamaha 4 stroke on my last boatgood motor economical to run  and plenty of power get ayamaha

Is 85hp enough with the current motor? I would be basing my decision on how well powered it is now, and then decide on brand/strokes etc after that.

I had an 18'6" chivers and if I was going an outboard I would have been relactant to go under 115hp. But I haul divers and gear so extra weight is normal.

I know people with every variation of current technology and they are all happy with what they have.

No idea exactly what your current engines weighs, but I'd guess that it'd be 250 - 300lb, and a new 115hp etec would be another 100lb heavier give or take.

You probably be better off with maybe a 90hp etec - thats at least closer to the ballpark of the weight you have hanging off the transom now. Unless the transom can handle more or you get it reinforced to handle a greater weight.

hi nifty...the 115 etec would be plenty for your needs....anything under that and i reckon you would regret it later. Look at the yammy 4 stroke 115 perhaps??

IN that size no doubt I would go 2 stroke, anything over 150 I would go a 4stroke. I had the 115 etec on my old 5.5m ali and it went like the proverbial shower. Probably a bit overpowered when we were not fully loaded but up north once we added gear, extra fuel, three blokes and camping gear it was perfect. Did over 300 hours in two years before I bought the new boat and it never missed a beat.

That said if i was to repower my current boat I would put a 200 or 225 yami on, but again that is because i think the fourstrokes give an advantage once you get around the 200hp range.

i would go the ETEC  115 if you want comparison take of power and dont mind the oil smell and extra hassle,  is you swiftcraft a Dominator ? as the others said you need to check what a 30 year boat can handle and you need to check your insurance as i have been told that when boats get  to a certain age they have to be inspected regurarily for insurance purposes.  my second choice for motor would be the 115 yammy 4st if the tramsom can handle the weight iam not a Mercury fan, also if it is a Dominator hull they can take up to 150 hp, i beleive swiftcraft are still in business in Kenwick area might be worth talking to them

Those older Swiftcraft were fairly heavy, better to go the larger horse option. You can always throttle back but once you reach WOT thats it btrother......there aint no more!

get a 90hp etec because hows the condition of your transom, can it old the 45% increase in weight?, or better yet youve been with a oldschool 2 stroke for how many years, why not stick with what you know, like a midrange 70, 90p oil injected yamaha so no premixing, great extremely reliable engine, not as fuel efficient as a etec but you know its gonna be working in 15 years, or a 115 saltwater series yamaha 2 stroke

115 etec= 170 kilos

115 saltwater series= 165 kilos

90 yami 2 stroke= 120 kilos= super light powerful 2 stroke!

i know it sounds logical to repower your older boat, but you got to weigh up the options. firstly , are you planing on keeping the boat for a long time or are you only going to hold onto it for another couple of years.if its the latter i wouldnt be going for any fancy e tech or 4 stroke as you will never get your money back on the motor.a 2stroke would be almost as good and the cost is a fair bit less. also as mentioned you will have to look at insurance. we had trouble with an old boat when we repowered with insurance and when we sold the boat we lost about 2k on the price of the motor and it was only about 12mths old, so we got nothing for the boat side of it 

Nifty,
The previous owner of our boat re powered our 30 year old swiftcraft explorer in 2000 with a 115hp mariner. They had to have the transom strengthened. Don't know the cost but I had it checked prior to buying and was advised it was done properly. It was done by Foothills Marine in Kenwick (Swiftcraft suppliers) and can swear that it goes like sh!t.
If you upgrade make sure you spend the extra $'s to get the arse end checked and strengthened.
Cheers'
David

There is a 18-19 foot (I think based on a drive by last night) swiftcraft parked in Kingsley with an etec on it. Might be worth knocking on their door to ask an opinion. PM me for the street if your interested.

Yeah I saw one down at woodies on Sunday, not close enough to get the details though.

Don't buy ETEC- take it from me.

The electronics fail on them.

70% of all pros buy Yamaha..must be some logic nehind that.

I've got a 300hp ETEC and would never buy one again

So nifty will the new motor be on before we go to mandurah in February???

Thanks to all for your help.

I have decided to get a Etec 115 which is being installed this week.

Nifty

i got a 150 salt water series merc and its a ripper- could get them cheap second hand but still in good condition