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Tomcat Steering Seems Stiff

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Joined: 22 Oct 2020
Posts: 9
City/Region: Sarasota
State or Province: FL
PostPosted: Mon Sep 13, 2021 10:03 am    Post subject: Tomcat Steering Seems Stiff Reply with quote

Our new to us Tomcat seems to be stiff to steer. I had it looked at by the marina staff here and they said it was due to the autopilot and couldn't figure out why. They removed the autopilot from the system and said it was working good. When I picked it up it still seems stiff to steer. Really didn't seem better at all

In my experience with other single outboard boats we've owned, I could steer it with one finger and the tomcat requires you to kind of pull it in the direction you want to steer.

I wanted to put a quick post out and ask anyone with a tomcat how easy it is to steer. Ours is stiff whether sitting at the dock or driving at higher speeds.

It has counter rotating props and seastar rams. The helm was replaced recently before we bought the boat so someone else has been troubleshooting the steering. The rams on the motors look to be original
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gulfcoast john

Joined: 14 Dec 2012
Posts: 799
City/Region: PENSACOLA
State or Province: FL
C-Dory Year: 2010
C-Dory Model: 255 Tomcat
Vessel Name: Cat O' Mine
Photos: CAT O' MINE
PostPosted: Mon Sep 13, 2021 3:40 pm    Post subject: Reply with quote

It’s a purely hydraulic system with no power assist which turns two 400 pound engines despite inertia and friction. I can’t turn my wheel when on plane or at the dock with one fingertip at 12 o’clock and wouldn’t expect to. However, when trimmed out properly on plane, I can take my hands off the wheel entirely and it will shoulder through waves and wakes and wind and current straight as an arrow until it runs out of gas. You can’t have both that and single fingertip sensitivity at the same time. It turns easily with one hand (most owners install an Edson knob, since it’s a LOT more wheel revolutions lock to lock than most systems). As a 145# weakling, I find it much harder to steer the self-propelled 80v battery lawn mower than the TC255.

There is not much to go wrong with well-designed hydraulic systems compared to electrical systems, and the VAST MAJORITY of such problems involve air bubbles (or other contaminants) in the hydraulic oil. The same issue seems to apply to hydraulic brakes on boat trailers.

When on the trailer, if you stand at the back of each engine, you should not be able to turn or twist it at all. If you can, there is air in the system.

With the wheel at neutral, remove the oil fill cap at the helm. The level should be no more than ½” below the top of the fill cap threads. If less, you have a leak.

If oil spurts out the fill cap in use, you have air in the system.

Download the SeaStar Liquid Tie Bar Manual here:

Since ‘the helm was replaced recently’ check the model of the new helm pump to make sure it’s designated for SINGLE cylinder applications; yours is in series, see page 5 and page 15, item 3.

Hopefully the helm was properly purged and air bled out then.

See page 13, System Check for a way to check for ram leakage under max stress without harming your system. The ram seals lead a hard life and eventually leak, but I haven’t heard anyone advocate that non-leaking rams should be replaced based on age alone. And new rams wouldn’t fix air bubbles in the system.

See top of page 13, Realignment Procedure. It takes two. Do it several times in both directions. If there are only some small bubbles, this might get rid of them. The valve will be aft of the battery shelf.

Although many Brats are comfortable with bleeding their own systems, I let the pros do it with their pressure pump every other year during annual service. I’m not allowed to do either due to marina and HOA rules.

If the ‘marina staff’ who checked your boat steering were certified mechanics doing service on an invoice you paid for, and you trust them, I’d suspect you’re dealing with a variation of normal. However, if this was some free informal buddy eval, I’d pay for a propper marine tech eval of this issue. Boat steering is a critical safety issue and nothing to fool around with.

We don’t have an autopilot yet; that just complicates the possibilities. If the helm pump and AP were properly sized and installed, normal operation vs air in your system seems most likely to me.

Hope this is helpful and at least gives you a few free procedures to try out.



John and Eileen Highsmith
2010 Tom Cat 255, Cat O' Mine
Yamaha F150, LXF150
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