Severe torque steer?

[reelfishin]

I got to messing around with a buddies boat the other day. It's a mint clean 16', '89 Bayliner Capri with a Force 70hp outboard. The boat is immaculate and has been garage kept since new. It probably don't have more than a few hundred hours of use on it. I drove it the other day after he complained that it was a real workout to drive. He said the steering was tighter to one side than the other. Not noticing a problem at rest, I took it out on the river to see.
It has a severe pull to the left as soon as you put it in gear. When in gear, even at idle, the wheel begins to steer left. At any sort of speed, you are fighting it constantly. Over 20 mph, it takes all your strength to go straight and right turns are a real chore.
I checked the steering cable, steering gear, and motor but found nothing out of the ordinary. The steering is rotary style, looks to be a Teleflex unit, the motor has a hydrofoil on it, he said the marina added that to gain a place to add tabs to counter the torque steer. They have them at full angle to correct the steering problem. I tried several positions, left and right, where they had them is the best option. I tried it with the foil off, it's twice as bad. The motor steers normal, there's minimal tension without slop in the pivot pin and the motor is mounted dead center and perfectly straight. There are no bent fins or skeg and the prop is what ever it came with new. He said he's gone round and round with it since new and nothing has ever helped.

The amount of steering torque is extreme. The minute you put this in gear, even at near zero speed, the wheel is pulling left. I took it up to about 35 mph, and at that speed, I didn't feel safe since it took both hands to keep the boat straight and a right turn was often a losing proposition. The wheel would slip back as you hand over handed to the right. I found myself doing wide left circles to go right. If you let off the wheel or relax a bit, the motor goes full lock to the left.

I though maybe something strange with the prop, but it looks fine to me, nothing bent or oddly cupped.
Trimming the motor down makes the problem worse, with the motor up, the problem is less but still bad. The motor is set with the anti cavitation plate about 1/2" above the bottom of the boat. One marine mechanic mentioned that if the prop was uncovered in the water it could create a serious pull, but the prop is well submerged and it does do it from the minute you put it in gear.

Any ideas?

 

[tashasdaddy]

Re: Severe torque steer?

2 in 2 days, have me stumped. thats a record.

 

[Splat!]

Re: Severe torque steer?

Just throwing someothing out here. Are the torque tab on the engine turned the correct way. If pulling bad to port, the tab should be angled port as well( I think, Gotta go look in a book to make sure). Not trying to insult you but I always look for the stupid goofy stuff first.

Yup, trailing edge should be moved in direction of pull.

Is it any better with the engine trimmed all the way in?

Bill

 

[reelfishin]

Re: Severe torque steer?

Just throwing someothing out here. Are the torque tab on the engine turned the correct way. If pulling bad to port, the tab should be angled port as well( I think, Gotta go look in a book to make sure). Not trying to insult you but I always look for the stupid goofy stuff first.

Yup, trailing edge should be moved in direction of pull.

Is it any better with the engine trimmed all the way in?

Bill

First, I tried the tabs both ways, both the one on the engine and the two on the hydrofoil that was added to correct this problem. I even tried removing the hydro foil to see if that might have made it worse not better but it does lessen the pull but ever so slightly.

Second, I did a model number check online, the motor isn't a 70 as it's labeled on the cover, the model number says it's an 85 HP, he knows nothing of why the discrepancy even though he's owned it since near new. Its an inline 4 cylinder, with through the prop exhaust, the controls say US Marine, but look just like the Quicksilver controls on my Mercury but mine don't have tilt and trim control. The motor model number is 853F9E. I have no idea why the cover says Force 70. It seems to run fine but isn't a real power house. I'd expect more from an 85 hp motor if that is indeed what it is. The compression is good, almost a perfect 118 psi across all 4 cylinders. I have no doubt that the motor is healthy and in good shape. Like I said, its never seen saltwater and is garage kept and well cared for. He treats it as if it were a much nicer boat than it is.

The one thing I did notice is that trimming the motor in all the way (Down), actually makes it pull worse. The further I tilt the motor the less it pulls but again, not a big change.

I've had boats that had a pull, but not like this. It feels like there's a 300 lb spring pulling the steering to the left while in gear, under power, (It pulls at idle but you can control it with a firm hand on the wheel). I want to try another prop but I have my doubts there too. The prop don't look any different than any other prop and there's no strange shape or bends. Besides, it don't pull the other way when in reverse. It does pull slightly in reverse but not so much you have to fight it.
I am thinking maybe a no feedback steering gear may work but I'm not sure even that will overcome the pull. It's bound to steer hard to one side even if the motor won't be able to move the steering wheel itself. I am afraid that the NFB steering would be just masking the problem.

I can't even call this just a pull, this thing wants to go left and left only. You have to fight will all your arm strength to bring it to right. If you pull it into a right turn, and let the wheel go, the wheel will spin wildly and slam the left steering stop with a load bang as the boat skips sideways into an abrupt left.
The hydrofoil makes that move even worse as it grabs the water and stops the boat hard in the stern. The boat seems to kick out easy in the stern on turns too. There's no such thing as a hard turn. My trihull turns and handles better. This feels like a sports car on ice when on plane. If I disconnect the steering cable, the motor turns by hand but does have some tension on it but it's equal in both directions. What ever is the cause is either water flow related or prop related.

I tried something else too, I pulled the boat bow up to a padded section of dock, I started the motor and put it in gear allowing it to push slightly against the dock, the boats stern immediately comes around to the dock on the port side even at idle. I have to turn the wheel full right to keep the boat pointed straight into the dock against the bumper. In other words, even at idle, the motor pulls left bad enough that I have to compensate completely right to make it push straight. It don't swing hard towards the dock but comes around fairly quick. The wheel doesn't really 'pull' but will self steer left if you let go. I realize this isn't much of a test, but it eliminates any hydrodynamic concerns on the hull since the hull isn't moving.

My thinking after that was that the prop is somehow causing the pull. If not, I have no clue, the motor is centered, mounted straight, I see no bends or damage and it's done this since new.
If it were mine, I'd just hang another motor or change props to see if it changed, but this being a Bayliner with a Force, I don't have anything for spare parts laying around.
They couldn't have all had a pull like this. The average guy wouldn't have been able to drive one of these things, and they would have never sold so many.

If it were mine, I'd have either found and fixed the problem years ago or gotten rid of the thing asap. I can see now why it never got much use, it's a real pain to drive. If I can, I'd like to get to the bottom of the problem on this, I can't imagine how anyone could put up with this for so long.

 

[jbstrate]

Re: Severe torque steer?

Im only a novice but considering all the info you've given us the only possible answer I can come up with is the prop blade is deformed your against the dock test seems to prove that the prop is the only thing moving!

 

[jbstrate]

Re: Severe torque steer?

1 more thing slightly bent prop shaft would hae the same effect
good luck

 

[22E6441]

Re: Severe torque steer?

How's the hull? Are there any nasty hooks in it by the stern? What condition is the hull? Is it possible that there is some wet foam in one side of the boat? Does it float level?

 

[haulnazz15]

Re: Severe torque steer?

I think trying out a new prop would be the best test. Find out the correct prop to be using on the engine, then swap it out. (not that the current prop size is wrong, but the 85hp may be different from the 70hp).