Hondas and their themostat housings

[smckean (Tosca)]

Well, I've owned my boat now for a little over a year; so it's time for me to spend some serious money (I've got to do my part to insure the "hole in water" type saying remains valid.)

I took Tosca to EQ Marine to have a 400 hour service done (the BF150 has 1000 hours on it, and is about 10 years old). When Carl called me the very next day, I knew the news had to be bad.....I sat down. It seems the thermostat housing is heavily corroded and must be replaced to the tune of an additional $1000. Carl suggested that this might happen if the engine was not properly flushed allowing salt crystals to form as the water evaporated out of the engine. OK, I can imagine that, but never have I or the previous owner ever, ever, allowed that to happen. The engine has always been flushed using muffs after every retrieve to the trailer. The boat did spend 6 weeks in salt water doing a trip to Alaska one time (but used nearly every day). It also sat more recently, engine down, in a salt water slip for about a month with infrequent use.

Has anyone has this experience? Anyone got any words of wisdom that might help me to see this unfortunate development as half-way normal?

P.S. Carl did mention that Honda has a service bulletin out on this "problem". I assume the bulletin says to be sure to flush your engine well after every use. It would appear that corrosion of the thremostat housing is a known problem with this vintage Honda engine.

[BrentB]

Is the new part different than the original?
Maybe the new part is made from a better quality metal or is coated


Wow that is expensive for a housing
I guess Honda is just as proud of their parts as Yamaha

[BrentB]

What is the price for a housing?

[journey on]

You know, I took Journey On (a 2005 boat with a 2005 engine) into Oceanside Marine for service once and came out with a list of item to repair. After looking at the list, I wondered what motor they were looking at, cause it wasn't the one that was on Journey On.

Now, EQ Marine is a reputable outfit, and so is Oceanside Marine, but I have looked at the 2 ea thermostats and their housing. Here is a link for Honda 150 parts where you can look at the exploded parts diagram, with prices. So here is my opinion, remember MY opinion.

The thermostat housing is prone to leaking and corrosion. I accept that and try to look after it. If it's screwed up there are 3 possibilities to fix it.

First there are 4 main parts involved plus associate gaskets, etc. The primary case assembly (covers the timing chain,) 2 thermostats and the thermostat cover. I've had problems with corrosion forming at the joint between the thermostat cover and the case assembly, but I've been able to clean everything up and put in new seals. That's cheap as you can see from the web site.

Next is where the chain case cover is corroded beyonde cleaning up. Thats the expensive part. If that's corroded one can do one of 2 things. First, there is a 19313-ZY6-000ZA SPACER which apparently fits between the chain case cover and the thermostat housing. That may be Hondas solution for cover corrosion. Check it out, if it works it's cheap. Second, one can replace the chain case cover. I assume it has an "early" engine, retail $600. Look at the price on the link if you want to DIY.

However, here is the THIRD ALTERNATIVE. Replace the thermostats and thermostat cover. If the case is badly corroded, clean it up and build it back up with JB Weld, available at your local hardware store for $10. It's an aluminum filled epoxy. I've used it on motorcycles, outboards and anywhere else I could. It's great for cooling systems. I even saw a mechanic patch a diesel engine combustion chamber with it in Papaete, Tahiti so the cruiser could get to New Zealand. Don't know how long it held, but the engine started and ran.

After you build it up, it can be ground and filed to the right shape. Again, in a cooling system, it'll last forever.

This probably is a DIY job. I don't know if any dealer today would do it. Up to you. Everything is right at the top of the motor.

Boris

[ssobol]

I once had a car that had the bottom of the oil pan as the lowest point. Bashed it in a few times. Then had to rush home before all the oil ran out.

Each time, I fixed the cracks by spreading JB Weld over the damaged area. Held up fine to the hot oil 'til the next time I hit something.

[smckean (Tosca)]

Thanks for the analysis journey on. Using your tips. I've been exploring around the internet. The only way I can make sense out of what Carl said to me on the phone is that the chain case is involved. He mentioned the thermostat housing, but he also said that a "kit" costs $600 from Honda. So I am going to assume what he was saying is that the thermostat housing leaks because the chain case seating is corroded. To fix it he must replace the entire shabang with a "chain case kit" -- which I see on the Honda site costs ~$600. He said it would involve ~$300 in labor.....hence the ~$1000 price tag with tax and all.

I am not a DIY'er when it comes to motors (I've never even changed motor oil in a car!). I am very good at electrical and electronic stuff, but mechanical engines are foreign to me. So JB Weld solutions are out for me. I'm going to have to have EQ Marine do it.

I'm wondering if I'm just unlucky, or do at least some 200x Hondas suffer from this problem even if they are treated properly. I hate to think that I have this problem just because the thermstat housing leaked and somehow pitted the gasket seat on the chain case (or whatever is the correct way to say what I think I'm saying ).

P.S. Now that I better understand what Carl was trying to say to me, I called him back just now. Yes indeed, it is the entire chain case that needs replacement. He did say that I could attempt to have someone grind down the corroded metal, and fix it sort of along the lines you suggested journey on, but as a certified Honda mechanic, he can only do it this "right" way. Interestingly, he did say that since there was a service bulletin on this problem, Honda would pay for this entire repair IF the engine were still under warranty....which, of course, it is not.

[hardee]

Just out of curiosity, while the boat sat in the marina for about a month with little use, was the shore power plugged in? Given some situations, having the shore power plugged in can rapidly accelerate a corrosion problem.

Leaving a boat in the water with the engines down in salt water seems to be an unanswered question. Some leave them down, and some leave them up; each with their own reasoning.

It's kind of like the twins and singles debate, and the plug in or out controversy.

I'm pretty sure Dave had a shore power system on that boat and if it was plugged into the marina systems power, you could have some galvanic corrosion happening.

Just a thought.

Harvey
SleepyC

[smckean (Tosca)]

hardee,

It was I who left the boat in a borrowed salt water slip for a month last summer, not David. And "yes" I did have the shore power plugged in. OTOH, I see no evidence of electrolysis (nor does the mechanic). The zincs are old and nearly as complete as they were when first installed. I also keep the batteries main switches turned off, and I have a galvanic isolator. BTW, I left the engine down not out of belief, but only because I never gave the issue a thought .

As I've thought about it, I suspect that the chain case and its associated components were simply a weak spot in the BF150 design back in 2005. Why else would Honda create a special "chain case kit" and service bulletin to facilitate the replacement of all those parts ($600 retail) totally at their expense? Altho, I could conceivably get the work done cheaper by grinding the case down etc, I'm comfortable spending the $1000 to fix it using the official kit because perhaps the parts in the kit have been redesigned in some fashion to eliminate whatever Honda thought was wrong with the design.....but then I'm only guessing here.

[hardee]

[journey on]

smckean (Tosca),

Did you ask about the "19313-ZY6-000 (or -010) SPACER *NH8* (Honda Code 9137126)" To me that looks like a plate Honda designed to seal off the corroded surface on the chain case and allow you to reinstall the thermostats without replacing the chain case. And since it's a Honda part, I assume that a Honda dealer would do it. You might call Boat.net to see what that part is used for. They usually have a good answer.

I usually try to get a good outboard mechanic that's not a Honda dealer, because they can try to salvage a bad situation. Since the motor is out of warranty, I'm surprised that a Honda dealer just has one way to fix it.

Boris

[rogerbum]

[tsturm]

The five Honda out boards I have owned (1980's 10hp, 1990's 8hp & 90hp, 2003 130hp & 20hp) have all had Corrosion Problems internal & external. All had always been flushed & washed after every saltwater use. I do not own Hondas for that reason. Bad alloy & paint process???

Yamaha has been flawless for 3 motors in all saltwater use. We will see how Suzuki holds up.

[journey on]

This is my second Honda engine. The first was a 9.9 (don't you love that number, they can claim HP to the nearest 1/10?) that I bought in the late 70's. One night as I left Long Beach to sail to San Diego it quit and the off-shore breeze didn't let me sail back in. Got towed in. The next day I took the motor to a mechanic next to Stan Millers sales. He told me that it was plugged with salt and Honda's didn't like salt water. Fixed it with no new parts.

I started buying 2 strokes, mostly OMC, and have had no problem since. Other than requiring a bigger gas can.

So here's my second Honda, a 2005. And it's been stone dependable. Great motor. Yes, a little corrosion around the thermostat housing, but nowhere else. Since that part is a pain in the ass and keeps recurring, I've taken steps to keep it to a minimum. I could have replaced it with all new parts, as any good dealer would do, but then I've got the problem again down the line.

So my thought is that maybe Honda has changed the new engines, but the older still has that design flaw. The chain case kit is just a collection of all the parts needed to install a new chain case cover. And if one wants to replace that every so often, that's a good way to go. But the problem needs a solution. If that spacer works, it's from Honda and they may offer it to help us who have the older engines, if 2005 is an older engine. It's an easily replaced item, costs $23 versus the $600 for the kit. The kit, BTW doesn't include the thermostats. JB Weld doesn't corrode either. So I tend to use that.

So, my thought is not to do it by wholesale part replacement that just pushes the problem downstream. I prefer a solution that prevents the problem from recurring. If that has to be done by a non-factory shop, so be it.

And the other fault of the Honda? Ready for this? The paint peels after it's been left in the sun for 5 years. It's a great engine, let's just fix the small problems permanently.

One other thought on the care and feeding of that Honda. I am guessing, but the "zincs" Honda sells aren't zinc, but some mixture which includes al and mg. I say this since I replaced the "zincs" bought from some place in Massachusetts, a replacement in themselves, with Honda "zincs" bought from Boat.net. The Honda "zincs" were a lot lighter than the ones I removed. Apparently now the recommended salt water anodes aren't just zinc but some mixture of magnesium and aluminum. Shows you that genuine factory parts are indeed made for your motor.

Boris

[smckean (Tosca)]

As rogerbum said, this time around I'm going to put my faith in Carl and Les.....a faith I have no doubt is well placed.

The boat is new to me, and I have a lot to learn. At this point, I'm going to err on the side of caution and be sure the engine is in the best shape possible. It concerns me that Honda felt they had to issue a service bulletin and replace the entire chain case under warranty at their expense. I just have to assume there was a reason for them to take that extraordinary step.

Next time, I will do more homework before I decide on a repair plan, and surely I will be less cavalier. As far as this problem is concerned, I will be taking off the thermostat cover, cleaning the area, lubricating it, and so forth on an annual basis from now on.

[Will-C]

I love Honda engines. We have a 2000 watt generator, a 3000 watt generator and a 6500 watt generator. My wife is on her second Honda CRV a 2015 a Honda Accord a number of Honda motor cycles and my daily ride is a Honda Civic. But for our boats we use Yamaha engines. We have had a 115 Saltwater 2 stroke and 2.5 hp dingy motor and our current 150 hp four stroke. That 150 is a 2009 motor and has only had water pump service and normal maintenance. Honda in my opinion has not addressed corrosion as well as Yamaha. In Florida which has a much higher salinity content I guess due to the warmer temperatures. Yamaha is an over whelming favorite appears in Florida. When we purchased our current boat the dealer said Hondas were heavier, slower and more susceptible to corrosion. I'm sure they are great engines but extra weight and corrosion issues were things I chose to avoid.
D.D.