Sticky Hydraulic Steering....any thoughts

Hi all,

My 75 has always been a real bear to drive. I have played around with the trim tab but haven't been able to releave the torque steer. Always had a 21p prop but am considering a 18p 5 blade to reduce the touque. Was wondering if the conversion to a teliflex hydraulic system would cancel out the steering issues; and if it truely is worth the $1,200 expense. Any opinions or comments would be appreciated.

Kevin-

This is an i/o setup but I dont think this matters.

 

The hydraulic will help. Shop around online, I think they be had for less. You could also try a torque tamer.

jim

 

Hi Jim:

Not exactly sure what a torque tamer is?

Kevin-

 

Is there a trim tab just below your cavitation plate on your outdrive? You can adjust it to change torque (pull) of the propeller on some types of outdrives, or outboards. On my outboard boat, I got the tab adjusted so that there was very little pull with the engine trimmed about right. In fact, I could steer the boat slightly left or right without holding the steering wheel by trimming the motor in or out. Do not do this until you know your boat very well.

 

Hi Daniel:

Yes; ther is a trim tab and I've adjusted it in the past to attembe to reduce the torque. I pull skiers out of the hole with the outdrive trimmed all the way down and once they're up, I'll trim up a bit to flatten the wake and reduce the torque. I'm thinking a flatter prop (17 or 18 pitch and four or five blade) may be the first step.

Kevin-

 

Kevin,

You did not say what your outdrive is, but a 17 or even a 15 pitch 3 blade prop is what I would try. I would not go out and buy a new stainless prop as an experiment either. They are too expensive. Either borrow a steel prop or get an aluminum one. The aluminum props tend to have less cup and I would try that. Once you arrive at the style and pitch you like, then you could consider a steel prop. The smaller pitch will tend to reduce the torque steer a little.

If you walk through the boat parking areas at the show ski nationals, you will see three blade 15 and 17 pitch stainless props. I know of one triple rig that is running 19's, but I think he is giving up some thrust (my opinion). Many of them tried Torqueshifts and High Fives about ten years or more ago, but they seem to have settled on the above.

If your trim tab is all the way to the stop, then you have a couple of alternatives. I have filed the stop down for more throw or you could use a torque tamer. They are actually intended for surfacing prop where the trim tab above the prop is out of the water, but it would give you some help if you are already on the stop. It is just a wedge that is fastened to the skeg (below the prop). Here is a link:

http://www.bobsmachine.com/Products/engine_torqueTamer.cfm

Adjusting the trim tab is always a compromise. Mine is on the modified stop and is ok at speeds up to about 30. At high speed it really pulls. I don't pull barefooters so I don't care. My high performance boat had Sea Star Pro steering system on it which helps a lot. The boat still is harder to turn in one direction at high speed but I had it well over 100 and it was manageable.

I hope this helps,

jim

 

Kevin,

I went back and researched your boat and I see that you have a mercruiser v-8. There is one more problem that can cause the torque steer to increase. As the outdrive moves up and down it slides against some surfaces on the gimbal that carry the side load. The load is always one one side due to the torque steer. It is an aluminum on aluminum contact and the surfaces gall and wear over time increasing the side play of the drive. As the side play increases the drive will actually move over the amount of the play when power is applied. This movement will increase the torque steer.

On the later drives Mercury put a teflon or similar wear surface in there to eliminate this issue. I had a drive similar to yours and I replaced the outer wear surfaces and milled a slot in the surface on the drive itself and inserted a stainless plate. The plate was screwed to the drive itself. I set it up with minimum side clearance and the boat steered much better. Stainless on aluminum will not gall. The stainless just polishes the aluminum. It is worth checking.

jim

 

Hey All:

Thanks for the thoughts and ideas. Jims latest post maybe the reason I'm getting bigger forearms while driving. I noticed more wear on the drivers side of the outdrive/gimbal surfaces and thought about a shim fix but haven't gotten around to it. I had the outdrive off a couple years ago to change out the lower shifter cable and dread having to get those damn exhaust and u-joint belows on again. Didn't have the "special mercury installation tool" for streatching the belows that was recommended in the service manual.

Didn't think the wear would change the handling characteristics that much but I guess it can. Jim, if you have any pictures of what you did to compensate, I'd appreciate a look. I may try a shim and reprop combo and then see if the tourque steer persists, in the spring...when the snow has come and gone.

Kevin-

 

I don't have any pictures, and I can't find my manual for that. It was a long time ago that I did that. I don't think you have to pull the bellows to make the fix, but I could be wrong. I did not use an exhaust bellows, just the slip together rubber joint. I changed several sets of bellows on outdrives and did not use any special tool. It is difficult though. They need to be in good condition because if they leak the boat fills up with water.

I replaced the gimbal ring (I think). It is the piece that the has the outer wear surface. It also had bad pivot bearings which also affects the steering. Then I laid the outdrive in a bridgeport mill and milled out the area that has the inner wear surface (only on the bad side). Then I fabricated a Stainless insert for the milled out area. I sized the stainless piece and the depth of the milled cut to give a fairly tight fit with the surface on the gimbal ring.

When you have lateral play in those wear surfaces, it causes the drive to shift over when power is applied due to the torque steer. The drive is now off center and increased the torque steer and the wear of the two surfaces.

jim

 

Hi Jim:

I attached a pic of the outdrive and it looks like I could shim the outdrive surface with out having to remove the unit, just have to remove the hydraulic cylinder, but I'm a little leary of drilling and tapping in the out-drive. the Gimbal housing would probably be a better option.

Kevin-