First make sure it's mounted dead centered and dead horizontal. Then adjust your zinc tab just above the prop to the side that it's pulling to and keep fiddling with the adjustment till it runs straight.
On the underside of the back edge of the cavitation plate,
is a zinc sacrifice anode that is also a steering torque
compensation tab. If the motor pulls starboard, loosen the
attaching bolt and twist the back of the tab a bit to starboard.
Retighten, and go for a test ride. Continue to adjust
until steering torque is neutral. If the zinc is missing,
you'll need to purchase another.
Tom's answer is shorter, but I have a picture,
and as we all know...this thread is useless without pics!
I am going to say that massive amounts of torque are due to a motor that is not mounted properly or some other major issue. I don't know what hull you have but microskiffs can be very sensitive. If you are sure you have the motor centered properly and you have the tab centered and the motor is not bolted down yet. Don't be afraid to try and adjust 1/8 - 1/2 in any direction to see if that fixes it. Anything more than a 1/2" then I would start adjusting the torque tab. If you can not get it to a neutral feel after all of that then its time for a Torque Tamer.
its torque....2 thoughts come to mind..
1. youre mounted too low...raise engine if cav plate is less/lower than level with bottom of hull..
2. adjusting the torque tab as mentioned may work, depending how high your motor is mounted......
im guessing youre using a stock-type aluminum prop...a good stainless prop will make a world of difference....
some of it, youll just have to get used to...my setup has a good amount of torque(pulling)...i cant let off my tiller when underway at all or ill be on the bank...on long straight shots, i make use of the steering friction lever...sometimes a pain to drive...oh, but the places my boat will go.........
Marshman made me think of another point. If your motor is jacked quite a bit up or you intend to jack it up then you can pretty much forget about the torque tab on the motor's cavitation plate because it will be too far out of the water to be effective at WOT.
Stainless over aluminum to fix a torque issue is a new one for me.
One other tid bit. Forum member Weedy is the only person with a Merc 25 2 stroke that I have ever seen be able to let go of the tiller at WOT and continue going strait for significant lengths of time.
Sorry to get your hopes up Tailchaser, not my outboard,
just a pic copied from an out of state ad to show the zinc tab.
All I have now is that 5 hp Nissan. Even that spends most
of it's time tilted up while I paddle/pole the shallows.
i had a 25 merc on a 14' jon boat and the torque was so bad that if i let off i too would have been on the bank or swimming.... solved the problem 2 ways
1. adjusted torque tab to max. setting ( this helped but there was still a noticeable amount of torque steer)
2. installed a sting ray trim tabs AND also installed the little torque tabs that mount under the sting ray unit to the max. setting. all of this resulted in neutral steering