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Honda 15s, initial notes

Posted: Wed May 07, 2014 5:55 pm
by eepstein
This is for anyone interested in the Honda 15s. I bought two this winter and paid to have them installed. I helped a bit and learned a lot. So with only 1.5 hours on the engines and still doing the early break-in period, I have an intial list of pros and cons.

Fast and powerful (at 4000 rpms, the boat was running 7.5 kts in calm, slack water)
Quiet, appear to be a good bit quieter than the Yamaha 9.9s
Easy start. Automatically adjusts the idle. Very high-tech-ish
Tachometers (How did I ever live without them) But, are also available on Yamaha 9.9s I think.
Got a chance to replace every aspect of the engines; cables, shift levers, hoses - everything but the fuel tank got upgraded.
The integrated water flush is easier to get to.

They are big engines, with only fractions of an inch to spare in the sides of the well, and I needed to cut the fiberglass at the back of the engine well so it would tilt up.
Had to replace the entire electrical harness. A lot of work, but gave me tachometers and new ignition switches.
My Telefex was okay, but the cables needed replacing. In the end, I opted to replace the entire system. The new shift levers are very nice, with integrated electric tilt.
The hydraulic lift brackets are a couple inches longer than the Yamaha 9.9s with hydraulic tilt, and always touch the water.
The engines don't tilt up fully out of the water. So in marinas, etc. Its probably best to tilt them down enough to keep the zinc underwater. (This is the biggest Con I think.)
Reaching the oil dip stick on the starboard engine is harder than the Yamaha 9.9. On the port side it is much easier.
The plugs are a bit harder to get to.
The engine cover is harder to put on.
The dealer recommend that the engines have two bolts put in the engine mount, as well as the clamps, to avoid vibration. This its harder to lift them to work on them.

So all in all, it was a lot of work and more cost. Time will tell if the inconvenience of maintenance and extra cost is offset by the added speed/thrust against tides and wind. I did not really want more speed, but with a heavily loaded boat, wanted more power against the wind and tide.

Drew recommended hull extensions. Probably a wise choice. Perhaps another year.

I'll post more as I experience more. I can also send photos of the cuts and such should someone need them.

Happy Spring,

Re: Honda 15s, initial notes

Posted: Fri Jul 11, 2014 5:05 pm
by eepstein
Now have 12 hours on them. Same on gas as the 9.9s (perhaps better), great speed (a knot or more faster then the 9.9s when motoring, 2+ knots faster when motor-sailing with the Genny). But the size is an issue as they can't fully tilt out of the water. They are noticeably quieter than the Yamaha 9.9s and start easier.

Did the first oil and gear lube change. It's more difficult than the Yamaha 9.9s. Have to remove the side of the cowling to change the oil filter.

Also had to move the zinc on the mount lower so it was in the water, as the lower part of the mount touches the water all the time.

I would categorize the honda 15s as being something between the convenience and light weight of the 9.9s and the power and sail drive issues of Yanmars.

I painted the lower units and mounts with anti fouling paint but over the winter will barrier coat and repaint as one would a sail drive.

Hope this is useful to anyone pondering doing the same thing.

Re: Honda 15s, initial notes

Posted: Mon Jul 14, 2014 10:21 am
by thinwater
If you are saying you put copper bottom paint dirrectly on the aluminum lower units, that is a huge no-no. I strongly suggest you get in the water and look at them right now. I would not hesitate to pull the boat and repaint if I saw anything amiss. The zinc will not help you much and the damage could be severe. Much depends on how good the factory paint is and how deep you are in the water.

I say this, not because I read it in a book, but because I made that mistake. Once, in a moment of stupidity, I painted the aluminum rudder pintles on a Stiletto 27--I had pits up to 5/16" deep 2 years later! That would have been clear through a lower unit!! A lower unit can be destryed by conventional bottom paint in a single season.

But do get a second opinion.

Re: Honda 15s, initial notes

Posted: Mon Jul 14, 2014 10:26 am
by eepstein
Thanks Drew. Actually I used outboard lower unit paint, made for this purpose. I use HydroCoat Eco on the boat bottom anyway, which has no copper.

Thanks for the thought.


Re: Honda 15s, initial notes

Posted: Mon Jul 14, 2014 1:52 pm
by thinwater
^^ Good to hear! The one sentence was ambiguous and I wanted to share you the pain. In my case it was a near miss; the holes were not in structural areas.