Towing position for Honda 90

[Connie Fisher]

Ok, need some more advise, please.

Just purchased a 19’ Angler in western Arizona, 1743 miles from here in Guttenberg, Iowa.

This C-Dory has a 2004 Honda 90 HP, four stroke.

Knowing absolutely nothing about Honda motors, is there a recommended towing position?

Any other helpful comments are always welcome and appreciated.

Regards,

Ron Fisher

[T.R. Bauer]

They need to be down if you have the clearance to do it.

[starcrafttom]

I always towed with it up and on the locks per the mechanic. You might as well ask " twin or single"

[JamesTXSD]

[journey on]

Just to beat the subject to death, here are a couple of thoughts I have on uppe vs downie.

First, the main thought for me is to reduce the load on the transom when I'm towing. We use the interstate and that's a rough ride. So what position puts the least load into the transom? The vertical load is the same no matter what the position, the motor certainly doesn't weigh less no matter how it's tilted. Now the motors moment on the transom (the torque the weight of the motor puts into the transom) is a maximum when the motor is down since the CG (center of gravity) of the motor is as far back as it can get. As the motor is tilted up the CG moves forward, until (I hope,) it's directly over the transom or even in front. That gives the transom a minimum inertial load as the trailer bounces down the road, just fore and aft shocks. So I try to get the motor up as high as I can.

Now, I can't tilt the motor up far enough to engage the lock, courtesy of the feedback pot for the autopilot. And so what, you say? Well, the motor is supported in tilt by the tilt hydraulic system, right? So when the motor is tilted up the rotational shocks are passed through to the transom by the hydraulic system, so there are hydraulic pressure surges as the trailer bounces down the road. That's why the factory installs that mechanical lock, to take the load off the hydraulics. So far I haven't blown the tilt hydraulics. And again, tilting the motor up whilst towing reduces the hydraulic loads, using the same rationale as above.

Any questions from the back of the room?

Merry Christmas, Boris

[thataway]

The other side of the coin is that there is more torque load on the transom when the motor is tilted up. So I leave it down. Some motor's manufactures say that the locks are not designed for trailering--just as a safety when mooring or working on the unit.

Then there is a Transom Saver--which is a crutch which fits over the lower unit, and takes that load to the trailer frame.

[T.R. Bauer]

[Connie Fisher]

OK, time out, take a deep breath, take a step back, let's think about this.

Through all the different opinions and resulting cluster, I did receive the following comment/s; from a trusted “voice of reason”.

If you tow with motor in the "down position" and go off the road or over a curb, be prepared
to replace the lower unit!  This applies if the trailer has the "torsion bar" suspension.  However
if trailer has "springs", you "may" have enough clearance to tow in the "down position".  The "locks"
on motor are very strong and with motor in up position, "weight" is almost perfectly balanced,
thereby reducing the "torque on transom" mentioned on C-Brats "posts".

Comments?

Regards,

Ron Fisher

[hardee]

And then there are the "alley gators" and other assorted scrap in the middle of the track. With the OB tilted up, the ground clearance increases. Also curb and driveway clearance, man hole covers, tank fill caps at the gas station or marina, and you might save the lower end there. All that and saving the transom too. Oh, by the way, my mechanics recommendation is to tow tilted up also.

And there is the stuff about twins spreading the transom load over a larger area, there goes that singles versus twins stuff,..... again

Harvey
SleepyC

[T.R. Bauer]

If there is any concern with your outboard making contact with mother earth during towing, you should tow with them up. But, that one is kind of a no brainer if you ask me....I'm pretty sure C-Dory recommends towing with them down (somebody has to know for sure) and there is referrence to leaving them down in transit in my honda bf45 manual. Do it matter all that much? Probably not......

[journey on]

Bob/thataway,

How is there more torque load on the transom when the motor is tilted up? From my view/analysis there's less.

When the motor is not tilted, I assume that its CG is in back of the transom, which could be wrong, but visually looks to be correct. The resultant torque is then the horizontal offset between the CG and the aft face of the transom time the weight of the motor.

As the motor is tilted up the engine block is moved forward, and this CG offset decreases. Of course the lower end/propeller moves aft, but the engine mass is dominated by the engine.

When the boat is sitting still this torque is a constant but when the boat bounces as the trailer bounces, the resultant acceleration on the motor imparts an inertial torque on the transom. The smaller the GG off-set between the transom, the smaller is the torque, since the motor mass remains constant.

As for the lock, Honda customer service said that the mechanical lock is there to relieve the hydraulic system, for storage or towing. I don't know about other motors. Also, the idea of a strut between the motor and the trailer is a good thing, but that's not possible with a 25 and an EZ Loader. If you know of one that works on a 25, please let me know.

Ron Fisher, you're correct in that the motor needs to be up to clear dips in the road, and we have one between the parking slab and our driveway, BUT the motor will kick-up when it hits. Your significant other will then discuss the incident with you, but if you were going slowly enough there is no need to replace the lower unit. I'm thinking of one of those red flags they use on aircraft to ensure that everything is in the right position. If I see it when I start the truck, I've forgotten something. Same for the plug in the transom. I've survived both bouts of stupidity.

Boris

[thataway]

First, it is granted that the lower unit must have adequate road clearance. With trailers which do not have that I have used either blocks of wood between the mount on the transom and part of the engine which rests into this mount. Several boats I have used the "transom Saver" or similar device. I have one of the rubber blocks--thanks to Charlie--but have not tried it. There are also devices which lock upper engine leg to the engine mount support (similar to what it does when in the down position)

With the engine straight up and down, the force is all the entire mount, and locked in. With the engine tilted up, it is free to bounce around--and the "lock" --which is basically a single cam, with a relitatively thin shaft, has varying forces--it is not constant as one goes down the road--especially with the pot holes on I 5 on Calif! I have seen these cams fail--both the cam bend, and the safe break. I have had mechanics told me that one should never tailer in this position--OK for storage, or keeping lower unit out of the water. Also the engine will go from side to side--putting stress (and potentially--does in some cases) blow the seals on hydraulic steering. The trim tilt cylinders are not made to take the jostle of road in the "trailering" position. The seals will be damaged in time if you trailer in the "up" position, relying on the tilt cylinder. When you use the motor up "lock" then the tilt cylinder should be powered down so that all of the rods are retracted into the cylinder.

The mass of the engine is now forward of the transom, and the lower unit is on a fulcrum well aft. The way to test for a weak transom is to put the engine all of the way up--and put a load on the lower unit--that is the same effect as trailering in the "up" position. The "pivot point is just aft of the transom--and the engine will pivot up and down as you go down the road.

Again--this is what I have observed--and has worked for me. Obviously this is an area of controversary and some feel that the engine should be trailered "up". I do what has worked for me thru the years.

Finally--Honda online manual--for the 115/130: Use the tilt trim lock for Mooring--no mention of trailering. Under transport "leave the engine in the running position"--if not possible" use a support bar to hold the engine up"--no mention of the tilt trim lock!

[jennykatz]

What we have done the few times we do trailer long distance we have put a 1by 6 board and rested engine on that This take the stress of the hydraulics . I feel the engine latch is way to weak to tolerate the bouncing of a trailer
WE have a torsion axcel trailer with the engine latched with board we have plenty of clearance from hitting sidewalks etc etc.
If one thinks about it the outboard hangs off the transom of go fast boats doing over 100mph and they slam back down so I think that's the best way to trailer with engine down .Just my 2 cents worth and this is what El and Bill have been doing for years with thousands of miles under their belt .

[retnavy]

I actually broke my motor toter (trailer support bracket) coming back from striper fishing just the other day. I hit a very rough stretch of road going into one of the tunnels on the Chesapeake Bay Bridge tunnel. The square tube snapped right in half. I think that thing is just thin aluminum. I do plan to replace it though just for insurance when trailering.

[Sea Wolf]