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Seahorse
24-07-2006, 06:11 PM
i have just ordered my 489 stacer runabout. the min hp is 60 and max 90. I ordered the boat with 75hp but i have soken to few people in last few days and mates have said go the 90hp. I rang the dealer and asked his advice and he said 75hp would be fine and 90 was not needed as it would only give bit extra top end speed.
Correct me if iam wrong but i would have thought that bigger motor means not as much load or push to do the same as smaller hp.
The extra cost is $1000, but hey extra now is cheap if i decided later on that need extra power.
I would like anyones views on what they have experienced or what they suggest, also do u think fuel usage would be similar.

cheers
greg

a_big_red_1
24-07-2006, 06:48 PM
hi Greg, are you talking 2st or 4st?, if 4st,
for the $$$$ i would go the 90hp ( in the Mercs the weight is the same 75-90 hp )
cheers
Daz

Seahorse
24-07-2006, 06:50 PM
its 2stroke

Spaniard_King
24-07-2006, 07:07 PM
stik with the 75.. same CC as the 90. I am with the dealer on this one..only goin to improve the top end.

cheers

Garry

Seahorse
24-07-2006, 08:51 PM
what extra top end would u say i would get. this size motor is all new to me. make the choice once and once only. want to get it right.

Spaniard_King
24-07-2006, 09:45 PM
Lets say you get 30 knots out of the 75 flat out... you may get 35 with the 90 but the 90 will chew a lot more fuel at 35

Garry

Seahorse
24-07-2006, 09:47 PM
ok. thanks gary. prob just save my grand and go 75hp.

cheers
greg

Dr_Dan
25-07-2006, 01:02 PM
Why not get the 90, and still only run at 30, going 3/4 throttle

HarryO
25-07-2006, 05:17 PM
Hi Greg.

Once you've got the Stacer loaded up, full fuel,
tackle, eskys,gear, and one or two mates on board,
you'll soon know wether the 75 will push it or not.

Just personally, I like a bit of reserve hp.

Seahorse
25-07-2006, 05:34 PM
iam confused. i was told to look up merc site. i did and the cc were identical, bore and stroke identical, gear identical. the only diff was in the flat out revs. the 90 said max 5500 and the 75 said 5250. so i guess this means only top end speed.
but if u had a 90 and run at 3/4 throttle would that be equal to more throttle on the 75.
sounds right but if cc are the same then it wouldnt make any difference would it

HarryO
25-07-2006, 07:32 PM
Hey Greg,

The differences would be in the carburettors, and manifold,
reed valves and piston crowns.

I suppose an analagy would be like buying a std V8 kingswood,
(now I'm showing my age) as compared to a Monaro,
with a 4bbl Holley and matching manifold.

Same capacity, but more horsepower. :)

Seahorse
25-07-2006, 08:14 PM
harryo, its all confusing. Iam really worried about making the right decision. Dont want to spend another$1000 if i dont need to.
If both motors have the same cc capacity, doesnt that mean the same power up untill nearly full throttle, where the 75 have top range of 5250 and the 90 has top range of 5500.
Garry what u said is prob correct. Same power of the mark and few mph difference top end. Iam agonising over this.

greg

Spaniard_King
25-07-2006, 09:04 PM
Greg,

you are agonising over it. The 90 will have different carburation and maybe.. and I do mean maybe a slightly different exhaust. By my money is on the carburation.. the 90 would have bigger jets and probably a bigger throat on the carby to allow more air at the top of the RPM range.

just about evvery outboard manufacturer down grades an engine to give them more of a range otherwise they need so many different models spare parts etc.

go the 75 if ya worried about carrying a load get a prop that gets the engine to rev more at the top end.. your not racing the boat so top end aint a matter performance is.

I bet if you ask what is the most common speed people travel at in there boats being inshore or offshore not many would brake 25 knots too often

cheers

Garry

Seahorse
25-07-2006, 09:17 PM
thanks gary. iam only going to make this decision once. its a biggie. i have already ordered boat with 75hp. i will sleep on it.

cheers
greg