Outboard offset???

Grant

Member
Joined
Feb 19, 2005
Messages
84
Location
Kenley,Surrey
Cruising area
Swanage
Boat name
How Fast Does That Go Then...
Boat make
Fletcher 14 GTO/ Sea-Doo RXP
Engines(s)
90 Merc/1.5L supercharged 4 stroke
Hello again,

I've managed to find myself a 90hp mercury for my 14' Fletcher GTO to replace the current 60hp.
However obviously the new outboard will need offsetting more than the current one due to the increase in power.
The current one is offset roughly 1/4 - 1/2 an inch.
Is there a formula to work out the offset needed, or how do i go about finding out?

Thanks

Grant

p.s Heres a pic of my boat
 

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Not sure I'd worry about it, unless you're having to drill new holes anyway. Reckon I'd just bolt the motor on in the existing location and see how it goes.
 
Matt said:
Not sure I'd worry about it, unless you're having to drill new holes anyway. Reckon I'd just bolt the motor on in the existing location and see how it goes.


I agree, wang it on in the same place....
 
Grant said:
Is there a formula to work out the offset needed


yus der iz. mesher de widf ov de fkin bote inn meeters att de blunnt ennd. harve dis meshurment, mulltiply bi de PH ov de enjin, deevide itt bi 60 an de anser iz wan therd ov dat inn inchis

gArf
 
Definitely just replace it, if after that you want to fine tune for speed, get a jackplate which will give at least 6" setback anyways.
 
Re: Re: Outboard offset???

The gArfish said:
yus der iz. mesher de widf ov de fkin bote inn meeters att de blunnt ennd. harve dis meshurment, mulltiply bi de PH ov de enjin, deevide itt bi 60 an de anser iz wan therd ov dat inn inchis

gArf

:drain:

yowm a nutter


Eh, you attending on the 16th in Sarfamton?
 
Gav said:
Keep up gArf


i amm verry bizzy att de mowmint dumpin sillt onn de brambuls bannk. i av manijed too chaynj de depf bi too meeters sow farr.

dat shud cach a feww ov dem ribnobburs owt:devilish:
 
Hi Grant

I have the same boat as yours but with a Merc 75. (same weight, less power/torque)

Mine was fitted by a Fletcher dealership using the guide plate & tables supplied and is offset by 20mm.

I would do as others say & just try it first. If you need to move it I'm not sure whether engine power or weight is the deciding factor; or even if offset makes any difference at all. Some say the engine should be dead central, others say it should be offset. I have never managed to get a definitive answer!
 
When it comes to offset. This is something that I used to do, seemed to work well. Rather than say offsetting a motor 1 1/2" I would offset about 3/4 and then tip the powerhead back to the center.
The effect of this was off set for the torque effect but put the weight back in the middle as best as possible.

No glasses so it's a rough one to get the idea across


Edit: to a point dont get silly and lay it over to far.
 

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Thanks for the help people, I haven't taken delivery of my 90hp yet but have been told that the I may need to drill new holes as the transom layout will be different form that of my 60hp?

Perhaps someone will be able to confirm this, my 60hp is a brownband but with the square casing (not oval wrap around) and my newer 90hp is grey band with the same shape casiing and its oil injected.

Thanks again

Grant
 
i used to have a boat like that!

i need a boat like that!
 
I sold my Flectcher arrowflyte all running on a trailer with a 60 rude in blue for £800 best and cheapest boat ive ever had £20 quid fuel would last me a 4 hour session and was t perfect ski boat only did 30mph flat out thought sounded like it was going to blow flat out, Oh and i sunk it twice out in the sea the waves use to come over the front :frog:

:drink:
 
I bought a new 90 Yamaha and it had a different hole pattern from the yamaha 55 i had fitted before it.

Noel
 
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