Press "Enter" to skip to content

Replacing a Trim-Tilt Unit on Your Outboard

So. I lost pretty much (hah! … all of!) the past summer on my boat. Well, I got the bottom painted, and all was well until the end of June when a simple little “Oh, go take the grandkids out for a ride,” from the missus, turned into a blown trim-tilt unit. Not the trim motor, not a part of it, but the unit rotted a hole in one of the hydraulic cylinders and that’s all she wrote.

Fortunately, at the time, I was about a half-mile from my dock, and the unit was down – although far from in ideal trim – so I was able to putt-putt back to the dock.

An aside. My boat – Irish G’Bye – is a 2003 cuddy, with a 150 Yamaha of the same vintage, and sits in the water pretty much from April-May until January, so 17 years out of a trim-tilt in saltwater ain’t nothing to sneeze at.

So, you replace it, right? Not for $4G’s you don’t on a 2003 engine (the best price for a new one I could find was $3600-plus)! And therein lies the tale.

What You’ll Need (or what I needed).

Pretty much all outboards are kinda’ similar, but whatever. There are some decent videos on YouTube that’ll give you an idea of what you’re up against.


• Ratchet and sockets. In my case it was 10 and 12mm sockets for a 3/8-inch ratchet. You’ll need a four-inch extension (this will do double duty).

• A means of getting corrosion off metal parts. I used a Dremel with a wire brush. If you have a drill press, mount a wire brush and use that to clean the large connector pins. Saves your fingers.

• A ring plier.

• A soft hammer and a metal one (you’re not framing a house…a regular non-handyman hammer will do).

• A Vise-Grip won’t suck.

• A pair of forceps won’t suck either (especially if you have several thumbs rather than fingers, as I do).

• Your phone or a camera. Take pictures of everything you do before you do anything. ANYTHING. No, your memory isn’t that good.

• Some take-out plastic food dishes to keep parts together.


The “trim” part of a trim-tilt are the two pistons that do the fine adjustment to your motor. The “tilt” part is the thing that gets it out of the water when you dock, or gets it up into position for trailering. There are a bunch of other parts, but I’m faced with replacing the entire unit, so who cares what they’re called?

There’s “usually” a screw that releases the hydraulic fluid (nasty stuff). If there’s a magic way to loosen that screw, I don’t know it. You’re supposed to be able to do it with a hefty screwdriver. I was able to trailer my boat with minimal (hah!) damage and, after semi-stripping the hell out of the screw, I called my mechanic and he did it with his magic wand (i.e., I have no idea how). Then it’s simply a matter of muscling the engine into trailer position and having someone throw the trailering locks down so you can call your doctor to fix your hernia.

If you look at your trim-tilt unit (let’s call it the “trim” from here on), you’ll see some wires coming from the unit. Pull the outboard cover and trace them. In my Yammie, there’s a blue and green wire and the boltheads are colored the same, blue and green. That you probably can remember. I took a pic anyway.

Doing It

Okay. Your engine is in trailerable position with the cover off …and the flaps that take the load off the hydraulic system down, so they’re taking the weight of the motor.

Shut the power off or disconnect the battery from the system. Trace the two wires from the tilt to where they hook up (in some cases they’re behind a plastic cove (10mm sockets seem to be the right size. The bolts on my unit were also 10mm) and remove them from the connection. The wires will be coming out with the trim unit. Put the bolts and washers back where they were located!

Before you do ANYTHING else, take a pic of how the wires are routed into the motor housing. More than likely you’ll be working with sun shining and can’t see exactly where or how they enter. The camera can.

The “tilt” piston is the single one going vertical to the engine. On mine there’s a C-clip on one side (starboard). Use the ring plier to gently remove it. No force necessary. Put it in one of the food thingees. The pin (about five-inches long and an inch in diameter) has plastic bushings on either side and the pin should easily slide out – starboard-to-port – using your fingers.

At the bottom of the trim there’s a pivot that holds the unit in the frame of the motor mount. There are bolts and washers on both sides (12mm for mine). Take the bolts out (into the food thingee … I wrapped mine in tape and labeled them. I don’t think it’s necessary, but ….).

As aforementioned, it’s a 2003 engine. The bottom pin (stainless steel – about eight inches long and an inch in diameter – a new one’s around $150), wouldn’t budge no matter what I did.

My solution? Heat and cold. A one-pound propane tank to heat the aluminum (expand it) and a spray can (that’s used for blowing grit out of your keyboard) held upside down on the stainless ends (to shrink them). Don’t go crazy. Hot, cold, hot, cold.

I took the four-inch ratchet extension, put the 12mm socket on it (the bolt and washer have been removed, remember! and start, somewhat less than enthusiastically, banging the pivot pin from port side to starboard.

Being right handed this involved smashing the crap out of the hand holding the extension and socket, but – slowly but surely – that puppy came out undamaged. No damage was done to the socket or the extension (both old school Craftsman stuff), surprisingly!


My mechanic said he’d be loathe to buy a used trim on E-bay. I hunted around everywhere, trying to find one that would fit (they are somewhat engine-specific). Phone calls, e-mails, called Yamaha, ya-da, ya-da, as the summer ticked past and my wife became increasingly ticked off about the boat in the driveway.

It was something for us to fight about besides home schooling, Corona-19, masks or lack thereof, living with each other, boat in the driveway (again), the election, etc., et al. Hey, I’m married 47 years. It passes the time.

Finally – and if this is a shameless plug, so be it – I found Five Star Marine in Port Richey, Florida (727-346-6912;, who not only confirmed that my unit was un-rebuildable after I sent it to them, but thought they had one that would fit.

Now, the summer is long gone by the time this happens, but — as noted — a new one cost around $4Gs, or I could buy a rebuild — with a two-year warranty — for $1400. Done. Good, friendly customer service people and rebuilders (you can actually talk to the guys who rebuild the units), quick turnaround, so I personally would have no qualms about working with them (hopefully never!) again.

We’re Close to the End – But You Gotta’ Install It

I get what looks like a brand-new unit via UPS and off we go. Naturally, it rains for an October-New York week. Okay. So, first day of the new week is tropical storm force winds. Then my job (which means writing deadlines … but still beats math and heavy lifting!) rears its nasty head. Anyway … eventually, a semi bluebird day and here we go.

It’s a relatively easy install with one slight problem. I’d Dremel-brushed out the pivot pin holes which had made getting the pivot pin out such a chore, so I assumed it would be a snap to reinsert it. It wasn’t.

The hard part is getting the unit’s holes aligned horizontally so the big stainless pin can slide through the trim unit and mate with the starboard side hole. There’s no tolerance in metal (who’d have thought!).

I dropped the entire unit once, I’m pretty sure I broke a bone in my hand hammering (using the ratchet extension and a steel hammer to get the pin set; Note: it might be a good idea to have someone helping with this), but eventually … ta dah!

Ran the wires (using the pics I took of how they came into the engine compartment), twisted the battery switch to “on” and … well, gahdamn! It worked.

Setting the tilt piston pin is a piece of cake … put the C-clip on and there you have it. A new – well, kinda’ — trim unit installed.

I cleaned the boat and got it shrink wrapped for the rest of the winter. I’m writing this in November and scallop season is a monster eco-disaster, as was last year, so that means it’ll be wrapped for maybe five or six months.

But I’ll be more than ready to go in April.