EFI Honda 90 help!

[Les Lampman]

Well, let me see if I can dip my oar in the waters here (and not splash anyone).

As has been mentioned several times Honda Marine has not issued a specific bulletin regarding replacement of the thermostat cover. The only place that reference to this exists is one short mention within Step #36 on Page 12 in Bulletin #73 (revised May 2012), which is a 16 page document, indicating the cover can get distorted from corrosion, and if it is distorted they suggest replacing it with the newer aluminum cover.

The lead in to the above information reads: "Earlier engines have a plastic thermostat cover" implying that engines built after the "earlier engines" already have aluminum covers. Which likely means the vast majority of engines do have the aluminum cover already since the bulletin was from just a couple of months ago.

The other thing to note is that the thermostat cover has NO bearing on the problem (Oil Dilution) being addressed in Bulletin #73. That is, the recommendation to change to the aluminum thermostat cover has nothing to do with oil dilution, it's only mentioned in the bulletin because the thermostat is being replaced as part of the actions called for in the bulletin. Said yet another way, a leaking thermostat cover is not the cause or a contributor to oil dilution.

The risk that a leaking thermostat cover represents is saltwater dribbling down the side of the engine. And while this is not something that should happen it is not a safety hazard and therefore is not a "Recall" item which has very specific legal requirements and procedures.

The problem with Service Bulletins or Product Updates and publishing them for any company is that some level of understanding of the underlying problem is necessary to evaluate what should or must be done.

For instance, let's say 1% of the Honda BF90D engines has a plastic thermostat cover that has become deformed and leaks (we know it's not all of them or there would be a Product Update from Honda, not just a mention in a service bulletin for another situation). If Honda (in this case but it would be the same for any manufacturer) issues and publishes a Service Bulletin regarding the potentially leaking thermostat cover then 99% of all owners who get the bulletin will needlessly worry about whether or not their engine is involved. Some of them may even needlessly spend time and money to haul their boat to a dealer only to find out it's not an issue. [You may argue my percentage assumptions but even if you make it 5% of engines that still leaves 95% without issues. It can't be anywhere near 25% because by then there would be a Product Update.]

There is no doubt that many C-Brats could check the engine and ascertain whether or not their engine has a plastic thermostat cover and then some (likely smaller number) may also be able to ascertain whether or not it's leaking. But the vast majority of BF90D owners wouldn't know where to look to find out or even have the desire to do so. C-Brats represent a small subset of owners and by their very nature are the more technically minded and/or proactive.

Also, the vast majority of outboards in the U.S. are not used in saltwater environments; freshwater boats far outnumber coastal boats. If the cause of leaking of the plastic thermostat cover is corrosion (due to saltwater) that means that, percentage-wise, very few BF90D engines are subject to the potential problem.

I understand the emotional argument that everything should be disclosed and information presented to owners. I also understand the practical implications of doing that. If I had to make a decision like that I sure wouldn't want to have thousands of owners spend the time and money to haul their boat to their local dealer only to find out they don't have a problem. That's tens of thousands of dollars potentially wasted not to mention the countless hours spent at the dealership level.

Outboard manufacturer's are subject to the same legal requirements as auto manufacturers with regard to recall issues. If there's a documented safety issue involved a Recall will be issued and every owner of record will get a notification.

In this particular case would it have been better for Sam to have known about the issue? Yes, of course, he's got one of the few BF90D engines out there that's experiencing a leaking thermostat cover. Was it an inconvenience? Yes, of course. Was it a safety issue? No. Had he never know about it he would have been able to finish his trip without trouble. Everything in that area, and the ECU most of all, is waterproof (makes sense for an outboard) and he has a better chance of winning the Power Ball lotto than developing issues due to the thermostat cover leaking. Of course it's different once you know about it, then you want it fixed so you don't have to worry.

We check the serial number of every Honda we service in the Honda Dealer database and I'm sure many other dealers do as well. What we get from that is sale date, warranty expiration date, and any outstanding Product Updates or Safety Recalls, there is no specific bulletin regarding the replacement of the thermostat cover. The database won't turn up a three sentence recommendation in a Service Bulletin related to Oil Dilution, so unless someone at the dealership is personally familiar with the information it isn't something that can be passed along to the customer. In this case someone would have had to remember a small bit of info buried in a 16-page document, which would typically only happen if you had engines showing up with the issue the Service Bulletin addressed (in the case, oil dilution). You might also know about it if a mechanic had previously seen it on an engine being worked on but that's pretty circumstantial.

I believe in this case, since Retriever was here, we may have been one of the dealerships that didn't tell Sam about the thermostat cover. We simply weren't aware of the problem because we haven't had any BF90Ds here with oil dilution issues (and that Service Bulletin is where the thermostat cover information is).

If Honda has chosen not to address the issue in a specific bulletin then it isn't a widespread problem (of course it's an "in your face" issue for Sam and I totally "get that"). Honda is not shy about taking care of customers and having dealers keep the engines running in top shape. Honda relies on their reputation for reliability more than just about anything else. In the 15+ years I've worked with them I've never had them deny a claim or even argue one. I have had them pay for work on engines far out of warranty but which they deemed shouldn't have happened anyway. They're not perfect but they go further than any other manufacturer we've dealt with.

Ye Gads! A wall of text! I should have thrown some photos in there I guess.

Les

[Captains Cat]

Or at least a or two

Thanks Les, cogent and well thought as usual! How is the Captain? (dusty)

Charlie

[20dauntless]

Les, I really appreciate you taking the time to respond to this and I spoke with Kathy yesterday and she was very helpful as well. I've now talked to Honda Marine (corporate) and three Honda dealers and gotten somewhat different info from each, which can be frustrating.

The local dealer here in Sitka said this is a common problem in his experience. Actually the only common problem on these engines, they're just about bulletproof otherwise. He was very concerned about the water on the ECU (and told me not to use the boat until it was fixed), hence my concern about the issue. It's good to know that it's not something I should worry about.

If this were to happen in the Seattle are it would be no big deal. The only challenge was getting the part up to Alaska, which ended up working out beautifully. One of the joys of cruising is problem solving!

I do still wish Honda had told me that there may be a problem with the tstat cover. I would have gladly paid the $20 for the more robust aluminum part in order to not have to deal with it. Oh well, live and learn.

The good news is the remedy is inexpensive and easy. Based on my experience, owners of BF90D's operated in saltwater should go ahead and swap out the tstat cover as preventative maintenance.

Thanks again for all the help!

[nuipukawai]

Les, thanks for covering this issue better and more completely than my late-night attempt. I agree with every word. Oh, and Mike, both the part #'s for the tstat and cover that you listed are invalid #'s....All Bf90d owners need to understand that their engine has 2 thermostats, one for cyl head, one for cyl block temp control. Different tstats, different covers. Aloha, Steve.

[mcolp]

Steve,

Thanks for the heads up on the part numbers. I transposed the numbers,
but as I understand it the correct number of the aluminum thermostat cover
is 19315-ZY9-000. If it is not then what is it? I was told that the correct
thermostat for the Block (60 degree) was 193-ZW9-003. So now what?
I 've checked my BF90D shop manual, Internet, and talked to Honda parts
guys. I got my 90 EFI in Feb of 2007 and believe me the first few months that
I had it hardly anyone, especially in this part of the country even knew much
about it. ( It drove the parts guys crazy)
I couldn't find spare plugs, fuel filters or much of anything for this engine.
Helm didn't even have the Honda Factory BF90D shop manual listed yet.

I realize that the 90 EFI has (2) thermostats. (Since day one)

All in all it's been a good engine. It starts instantly after sitting all winter and
runs really well.

Separate Issue:
The only concern that I have is that the oil gets really dirty really quick and
has a strong odor (A noticeable fuel smell) which leads me to believe that
fuel diliution may be an issue. (Not a big issue)
I've always used Honda Marine 10W30 Oil for those that may have thought
that I use el cheapo oil.

Please don't flame me guys, but that only reason that this Original post caught
my eye is that as a mechanical engineer for 3O+ yrs at hp I know what can
happen when supposedly sealed electrical components, cables and sealed connectors get around salt water, bad things can and do happen.

Could someone out there please let those of us that have Honda 90 EFI
engines know what the correct part numbers are for aluminum thermostat
cover, O-Ring for the cover and both Thermostats for spares.

Thanks,
Mike

[Will-C]

I wonder if Honda marine dealers make it a routine to check the Honda EFI 90's that might suffer from this leaking plastic t/stat cover by actually make it part of the inspection process during routine service and have the new metal covers in stock to put on the engines that see salt water use before they even start leaking as a preemptive meaure?This would just would seem like a common sense move. In our business we use serial numbers to identify possible problems and remove the stock and make corrections existing stock before it gets to the customers. We send our own tech updates to our own customer base to advise them of possible issues with products we have sold so they are not blind sided. They are worded in a way that does not cause mass hysteria.
D.D.

[Mike B]

The first of September I had some friends on the boat all day, and far from home. The next morning I went down to do some clean up and polishing then planned a quick ride at sunset. Well when I went to start the engine all I got was the engine turning but no start. I have never had a problem starting the 2007 Honda 90, so this was a little un-nerving. I'm lucky this happened at my slip and not in NY Harbor.
The problems were #1, a corroded 10 amp fuse on the engine (The bottom fuse). I noticed when I was trying to pull the fuse it seemed stuck. when it finally came out, one of the prongs just fell off into the water. It had corroded off leaving a good amount of gunk stuck in the fuse block, it was also blown. At first I thought the problem was just a rare, not very explainable occurrence. As clean and polished the engine looks I never expected what I found next.
After I pulled all the fuses and replaced the bad one (I put dielectric grease on the fuse connections) the engine started up first time. I think that fuse controls the fuel pump. Well I stood there admiring what a good job I did and how lucky I was to be doing that job at my slip and not in any shipping lane when I noticed problem #2,a small drip at the bottom of the engine near the bottom spark plug. It took about a second to recall the subject of this thread and find the leaking T-stat cover that was mentioned. If I hadn't read your experience with this problem it may have turned into an even bigger deal down the road...or channel.
I'm getting the part from Boats.net, when I asked on the phone they told me the part # on their site was the Aluminum cover , but they see a different # on their screen and sent me the wrong part, no problem the correct part (11-19315-ZY9-000) is on the way no problem.
If I was paying more attention in July when I read your experience I would have gone out , checked, removed and replaced that part .
If you have this engine make sure you have spare fuses on hand and do some preventative maintenance, spend the few dollars and change that cover.

Mike B
Remembrance

[mcolp]

Mike,

Thanks for the heads up. I went ahead and ordered and received the new
aluminum thermostat cover and also got a spare thermostat just in case.
I'll make sure I've got spare fuses also. Lake Powell is no place to be
stranded (or anywhere for that matter)

Thanks,
Mike
Allyson Marie