Difficult to steer 150 Blackmax 1985

[Catfish1972]

Hey...

First post, can't figure this place out.

Have merc 1985 150 BlackMax outboard on 18.5 foot Invader fiberglass ski/fish/bowrider type boat. Single cable steering. Pulls like a fiend at high speeds. The odd trick is, it pulls in different directions with no apparent cause. Might pull super-hard right at WOT. Then if I stop, crank it up again, it might pull hard left. Then it pulls right at half-throttle or lower.... next time, it pulls left. Very very hard pull at high speeds, and it WILL roll all the way to the lock if I am not holding on to the wheel. It has an aftermarket "planing fin" on it.... The cable seems just fine, as I can easily turn the wheel lock to lock out of the water. Very little actual play in the system. Just pulls like crazy in whatever direction it wants. Could throw an inattentive passenger overboard. I can move the engine side to side quite easily, which seems to rule out the cable binding up...

What is this all about?

Cheers!

Happy trails,
Catfish1972

 

[Chris1956]

Re: Difficult to steer 150 Blackmax 1985

Does that motor have the small zinc fin above the prop? If so, you can loosen it's bolt and adjust it. You can only adjust it to compensate for some pulling, not all, usually.

Normally a boat will pull right when the trim is in, and left when the trim is out. You do have power trim? if your boat is doing something different (sounds to me like it is), that doel fin is probably to blame. You might remove it and see if the situation improves.

 

[Catfish1972]

Re: Difficult to steer 150 Blackmax 1985

Hey, thanks for the reply... yes, it has up/down power trim, and yes it does have the little fin above the prop on the bottom of the cav plate. It is already adjusted a little to the left. I don't have a socket deep enough to access it, but I will get one ond give it a try. I haven't noticed if the trim is having an effect either way, but I somehow doubt it could produce this level of pulling ... I will check it out...

Thanks!