2021/2020 Yamaha DF2.5 4 Stroke - Stiff steering under load

[Romans5.8]

Just received a Yamaha DF2.5 this week (I forgot to look at the mfgr date. If it's after July 1, 2020, that would be a 2021 in MO. But I doubt it is. Anyway...)
Took it for my first run on a Sea Eagle SE9. That's a low pressure hull so a flexes a bit, which may be part of the issue. I'm going out today to play with the trim adjustment (It's a fixed trim with several positions).

The issue I'm having is at any throttle position above idle, it's hard to steer. Even with the steering tension adjuster loosened almost all the way. At idle it easily and freely moves. Under load, I have to yank it to steer and it's very stiff and jerky.

Any wisdom?

 

[Sea Rider]

That motor needs to work while sitting at 90º on transom, motor mount whichever. If trimed up or down from ideal 90º the lower plates will exercise too much drag which will inevitably harden the steering condition. The material with which the inflatable was assembled with being a thin unsupported pvc material also contributes with the flexing where the motor mount is installed on.

Motor height, bad trim, thin boat fabric flexing the motor mount will also contribute for that issue to happen. Will need to throttle just enough to avoid that condition, but could turn into a slow boring boating solution..

Happy Boating

 

[QBhoy]

Agree with searider. Likely to do with the trim angle. Sounds like it’s way down and thrusting low.

 

[Sea Rider]

If the steering bolt which controls the friction load on the steering shaft has been fully released as to turn the motor at neutral with 2 fingers, it's definitely a trim angle and motor mount fexing issue and nothing can be done..

Moons back used to have a french Sevylor K-86 inflatable powered with a demo 2 stroke Merc 2.5 HP motor, experienced same issue. The bummer was due to the boat was poorly built with a thin unsupported pvc cheapo material and impossible to pump it any further from a firm condition or risk achieving a......Kabooon bye, bye inflatable LOl !!

Then changed it for a high density thicker material 280 inflatable, although was inflated to it's max working pressure while powered with a 2 stroke 5 HP motor the motor mount still flexed a lot when more throttle was in demand, so had to use it at reduced fast boring displacement speed to take the max out of that combo. Anyway was much fun to use it that way than rowing it. LOL !!

Happy Boating