Re-powering boat
Submitted by joycey on Thu, 2011-12-22 20:20
Hi guys, bit of advice please.
Looking at buying a used 2003 haines signature fibreglass boat that has a Mercury 90hp 2 stroke on it currently.
Boat is underpowered, so I would want to re-power with a new 115-130hp 4 stroke.
Would get it done through boat dealership.
Just wondering is this a problematic thing to do, or will it be an easy thing for the dealership mechanics to do without leading to any issues with the boat set-up etc...?
Cheers,
Michael.
aaasnapper
Posts: 218
Date Joined: 15/01/10
Yeah they would. A brand new
Yeah they would. A brand new 115hp 4 stroke yammi is about $16-17K, minus the trade in for the merc. which would not be much I would suspect.
Other option is to sell privatly. Maybe look at a second hand motor with low hours.
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fishy fingers
Posts: 1719
Date Joined: 28/04/07
Sell privately
I just sold my 11 year old 115 hp johno 2 stroke for 3250 so there always a market you wont get much trade in though ( I'm getting a 140 suzuki)
smash
Posts: 434
Date Joined: 01/12/10
Ive got a 115 yam 4s
but value for money etc Id get the 140 Suz. Same weight, cheaper and good donk.
Both have impeccable reputations and are proven operators having been in service since early 2000's
strike_zone
Posts: 403
Date Joined: 09/09/10
dont go less than 130hp
or you will find your performance will not improve rule of thumb of 2stroke to 4 stroke performance figures is add another 25% more hp for the 4 stroke to at least equal the performance you get from a 2 stroke
sarcasm0
Posts: 1396
Date Joined: 25/06/09
Maths?
90 x 1.25 = 112.5?
130 / 90 = 1.444~
44%?
pelagicyachts
Posts: 1322
Date Joined: 23/02/11
"Dont go less than 130hp
"Dont go less than 130hp or you will find your performance will not improve rule of thumb of 2stroke to 4 stroke performance figures is add another 25% more hp for the 4 stroke to at least equal the performance you get from a 2 stroke"
I assume you mean "holeshot" or "acceleration performance" is lower? - a 115hp 4 stroke is still 115 horse power right? -assuming it is propped the same you should get better performance but same top speed (at same rpm)
smash
Posts: 434
Date Joined: 01/12/10
I agree SZ
The "25%" thing may have applied when the only 4stroke was a honda at 50% extra weight but nowadays there is only a few kgs difference
strike_zone
Posts: 403
Date Joined: 09/09/10
NO CHANCE
there is no 4 stroke on the market that can match a 2 stroke of the same hp in hole shot acceleration the mercury verado comes the closest but imagine if you put a supercharger on a 2 stroke
smash
Posts: 434
Date Joined: 01/12/10
that may be
but what good is holeshot other than for waterskiing and also I guess pushing along in rough water where you need to work the throttle? Id wager most amateur fisherpeople would choose the economy, sound, smell and longevity of a 4 stroke EFI over a carby 2 strokes holeshot?
But this is off topic, the discussion was whether you need a 4 stroke HP to be 25% over a carby 2S for similar performance on a fishing rig-I say no unless you need the holeshot for some reason.
joycey
Posts: 251
Date Joined: 28/05/11
Thanks for the info guys. My
Thanks for the info guys.
My other question is how do I decide what motor shaft length suits my boat.
The boats specifications state the transom length is 25 inches.
Do I need a Long or Extra-long shaft on the motor ?
Cheers,
Joycey
till
Posts: 9358
Date Joined: 21/02/08
You pretty much have to buy
You pretty much have to buy whatever is on there now, unless you modify the transom.
You measure between the transom and the cav plate IIRC and 25" is extra-long.
Dizzy
Posts: 753
Date Joined: 21/02/11
Yep, 25" transom requires an
Yep, 25" transom requires an XL shaft.
aaasnapper
Posts: 218
Date Joined: 15/01/10
I know of a 115hp 4 stroke
I know of a 115hp 4 stroke yammi for sale with only 140hrs on the clock.
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damo6230
Posts: 2029
Date Joined: 07/06/08
motor upgrade
look at a 140hp Suzuki as it's 3kg lighter than the 115.
She would push you along sweet.
glastronomic
Posts: 892
Date Joined: 16/02/11
Why not use the boat as is
Why not use the boat as is and what you paid for?
underpowered is only a relative issue, just use it wisely and enjoy the traveling you can do in it.
Plenty of your boats with these 90HP eggbeaters on them, so it can not be that bad.
Tomcat
Posts: 614
Date Joined: 24/02/11
Agree
Your not going to get much for it and new motor is going to give you a bit more at what cost I've got twin 90 mercs there great on my 3rd set run it till it stops then trade up
Longole
Posts: 55
Date Joined: 20/02/11
I have a 140 suzi on my 5.3
I have a 140 suzi on my 5.3 Haines Sig and am very happy with it. Jumps out of the hole well, slightly better than 1Nm per L, can talk easily to person next to you at 30knts/5000rpm. The 115 suzi on the same hull was similar, tiny bit more fuel and bit slower but also cheaper to buy.