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BF225 exhaust guide seals replacement necessary?

jamey

Member
Hello,
Two weeks ago I did an internal anode job on one of my 2005 BF225's. I replaced all o-rings and gaskets involved with the job, but forgot to order new exhaust guide seals, so I re-used them. They were in good shape, and had some silicone in the same area, so I carefully scraped out the silicone, cleaned the seals, and reinstalled the manifolds with a small amount of Permatex Ultra Copper on the exhaust side of the guide, making sure not to get any on the seals. Tonight I did the same job on the other motor, but replaced the seals with new ones. The old ones looked and felt fine, the rubber was smooth and plyable, and felt snug on the manifolds. Also the new ones were kind of a PITA to install.
So my question is, is it mandatory to replace these seals when the manifolds are removed, or is it ok to re-use? I don't want to risk anything catostrophic, but dont want to take the engine back apart either unless advised to do so.
Here's a photo of the seal. It is dirty in the picture, but looked new after wiping it off.
Thanks.
IMAG0544.jpg
 
Personally, I would replace them both. But given where you are, I would test to make sure you don't have an exhaust leak there, and if not, let it alone. Periodically test around that joint to make sure a leak hasn't developed.
 
Jamey - BTW - what kind of shape were your internal anodes in? How many hours on the engine?

One of my gripes with Honda design is that you need to remove the manifolds in the first place to get to the internal anodes. Seems like they could easily have engineered and external bolt in anode for each manifold.
 
Personally, I would replace them both. But given where you are, I would test to make sure you don't have an exhaust leak there, and if not, let it alone. Periodically test around that joint to make sure a leak hasn't developed.

Thats the thing, the seal either keeps water from entering the exhaust, or maybe exhaust from entering the water jacket, but I'm not sure how you would know unless there is white smoke coming from the exhaust or something. The manilfold itself has a new o-ring in this area, sealing the whole section from the outside, so if there was a leak, you wouldn't hear it. It also seems to me that since the seal is made mostly of rubber, that raw exhaust would tear it apart, so it is more of a water seal. It's almost like honda used silicone to seal the exhaust, and a seal for the water, but there is no mention of using silicone in the Honda repair manual.
 
Jamey - BTW - what kind of shape were your internal anodes in? How many hours on the engine?

One of my gripes with Honda design is that you need to remove the manifolds in the first place to get to the internal anodes. Seems like they could easily have engineered and external bolt in anode for each manifold.

700 Hours on the engines, Internal Anodes pretty deteriorated. Also, the thermostats on the left side of each engine had a good amount of corrosion, and the right sides were fine, proving to me that using the flushing attachment does not do a great job of flushing the engine. I will post a couple of pictures in a minute
 
Job took me about 3 hours or so on each engine, taking my time. As an auto mechanic, I feel perfectly confident leaving the seals alone, but was hoping an outboard mechanic would chime in

IMAG0540.jpg

IMAG0543.jpg
 
Thanks for posting the pics. It's the first ones I've seen of that area. ( I haven't done mine yet). Ditto's on the flushing effectiveness .I flush faithfully with Salt Away and am still getting build-up!!
 
Another couple of ugly pictures. The Service Manager at the dealer recommended this job every ten years. I'm going on 7. Glad I didn't wait

Shot of the left thermostat. I'm not sure what to do about it, but it is probably 1/8 of and inch from eating through the block and leaking.
IMAG0563.jpg


Shot of one of the power trim units, a result of not being bonded properly? Notice how the engine bracket looks new. The engine bracket anode looks new too.
IMAG0545.jpg


Main power harness to the engines. Wires appear not to be tinned, lugs not sealed, and this corrosion extends all the way, under the insulation, up to the engine cowls.
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I might send a letter to Honda, see what they say. Wish I had an email address for them.
 
Just a little history, this is on a 2000 Boston Whaler outrage that my father bought new, and had repowered in 2005. He is handing the boat over to me this year, and I decided to give the boat an overhaul. I saved the engines for last. I keep it in the water from April thru December, in Somers Point,NJ. The engines were flushed after every use with the flushing attachment.

Here's a shot of one of the power trims after I cleaned and recoated it. I also added a bonding wire, something that Honda started doing in 2006.
IMAG0562.jpg
 
Uggg. Just found a thread here about the vertical shaft bushing, and looking at pictures I took of the lower units when I had them out for water pumps, the shafts are definately worn some in that area. Guess I'm pulling them back off. Also just found out about SB #56, and I doubt that was ever done either.
 
Jamey,

WOW - That's some ugly stuff you have there. Thanks for the pictures on the anodes - that was VERY helpful to me, and I'm sure, others.

It's becoming painfully obvious to me that the flushing procedure is not doing its job. Not sure how to engineer around that. You don't want to be removing the t-stats after every use and I see no obvious path for intervening into the cooling system for more effective flushing..

There is some way to check whether SB#56 has been performed by a dealer on your engine, but not sure how it works - Mike, Jimmy, or Racerone can probably help you out there. Aristikat, on this forum, performed the whole thing and posted many good pictures and details. The Service Bulletin is pretty clear on the procedure, but as always the devil is in the details.

Below is a list of problems and faults with the 200 and 225 Hondas that I have gleaned from this forum, and others.
Engines Affected
Severity
Fault
(SN's or Years)
Fix
1
Engine block corrodes from the water jacket through to the outside in the V
??? Some models
Replace water jacket and possibly block
1
Intermediate drive shaft bearing failure
2007 and earlier
Replace bearing and possibly intermediate cowling
2
HO2 Sensor failure
2007 and earlier
Install new exhaust tubes per SB#56
2
HO2 Sensor failure (cracks internally)
1000001 - 1509999
Replace HO2. Some units require new ECM per SB#70
2
ECM does not detect HO2 sensor failure
1600001 - 1600527
Replace ECM per SB # 71
3
Must remove exhaust manifolds to check/replace internal anodes
All
Possibly install bolt-in anodes.
3
Upper cowling tends to warp and not fit together well
All
Use heat gun and ratchet strap to re-seat. Apply silicone to seam
4
Fresh water flushing system inadequate
All
None known.
5
No NMEA 2000 interface
Pre 2010 models
None known.
5
No gaugeable heat sensor
All
Fabricate your own
5
No gaugeable water pressure sensor
All
Fabricate your own
 
Thanks for your help! I'm glad I came to this forum.
I'm thinking I may clean the area that is corroded in the thermostat cavity with a die grinder, carefully, and pack it up some with an epoxy like JB weld. I figure it cant hurt as long as it has good adhesion. I have a feeling there are going to be alot of BF200/225 owners out there in for a big surprise when water starts leaking from that area, and its not the o-ring. My father flushed these engines after every run. It looks to do a good job on the starboard thermostat, but the port is obviously not being flushed. That flushing system is a false sense of security.

Anyone here flushing their engine while in the water, with a pair of muffs? I have a pair that feeds from both sides, and they do a great job in the driveway, the springs are tight and provide a good seal.
 
Not sure the muffs, even good ones, are much better. I've used the dual muffs in driveway. Heat alarm goes off after about 10-15 minutes.

As for grinding out the crude in the t-stat cavity and filling with JB weld, that is likely what I would do. I would first talk to a professional welder who had lots of experience with cast aluminum and see what they had to say. There may be other, better options for doing that from more experienced folks of this forum.
 
Jamey,

I just did the exact same thing this week , I used the boats.net site to figure out the gaskets and left out the to exhaust guide seals that weren't shown in the parts list under exhaust. they were in a different section . Anyway what is the verdict, i just ordered 2 but am not looking forward to taking everything apart again. i probably will but i'm curious.

on a side note , my internal anodes looked much the same , diffently some corrosion but enough left.the water jackets and block were spotless my engine has 900 hours it's an 02 and is rarely flushed (saltwater mooring field). i have had the midshaft bearing go and replace midsection, now i grease it religiously.
 
Jamey,

I just did the exact same thing this week , I used the boats.net site to figure out the gaskets and left out the to exhaust guide seals that weren't shown in the parts list under exhaust. they were in a different section . Anyway what is the verdict, i just ordered 2 but am not looking forward to taking everything apart again. i probably will but i'm curious.

on a side note , my internal anodes looked much the same , diffently some corrosion but enough left.the water jackets and block were spotless my engine has 900 hours it's an 02 and is rarely flushed (saltwater mooring field). i have had the midshaft bearing go and replace midsection, now i grease it religiously.

Hi Mike,
After careful inspection of the seals I removed from the second engine, I decided to leave the seals in the first engine alone. I think fresh high temp silicone on the exhaust portion, and re-using the seals is probably fine. The old ones from the second motor felt nice and snug on the manifold outlet.

I also ran both motors last night on muffs, no sign of any leaks.
 
Jamey,

i also ran mine and didn't see any leaks but i think your right in saying you wouldn't see any leaks because of the o ring sealing it. I ordered the guide seals yesterday after reading your post , unfortunately they are on back order and i'm dieing to get out to the cod grounds which open Monday. I think i'll play it safe though. i'm hoping to fet another 1000 hrs out of it .

ps. if you had just done yours a week ago i would have read this and done mine right or conversely i might never had read this and never known to do them. in the end i'm just going to suck it up and do them over . thanks for the input.

i'm just happy everything looked good inside , i was a little nervous because i can't flush the engine out on my mooring and it's been in the salt for 8 years.

there certainly is a wealth of knowledge on this site.
 
Jamey,

i also ran mine and didn't see any leaks but i think your right in saying you wouldn't see any leaks because of the o ring sealing it. I ordered the guide seals yesterday after reading your post , unfortunately they are on back order and i'm dieing to get out to the cod grounds which open Monday. I think i'll play it safe though. i'm hoping to fet another 1000 hrs out of it .

ps. if you had just done yours a week ago i would have read this and done mine right or conversely i might never had read this and never known to do them. in the end i'm just going to suck it up and do them over . thanks for the input.

i'm just happy everything looked good inside , i was a little nervous because i can't flush the engine out on my mooring and it's been in the salt for 8 years.

there certainly is a wealth of knowledge on this site.
Just be patient installing them. They are mostly rubber with a flexable metal rim, and bend/distort very easily. In fact, the new ones I got from boats.net were a little distorted out of the bag. I didn't have any seal drivers at home, so I used a trim tab anode that was the same circumference to start driving them in, and a punch and hammer to carefully seat them. They are tricky, thus the reason I decided to leave the first motor I did alone. Also, pick up some high temp silicone to replace what was there. I scraped out all of the grey stuff, and used Permatex Ultra Copper, same stuff I use at work on slip exhaust header joints. Keep in mind this is just my opinion that old ones are pefectly fine to re-use. I was hoping an outboard mechanic would jump in and say "No, I never replace those." or "Yes, absolutely replace those."

So your saying no corrosion in the thermostat areas?
I'm curious what temperature these engines run at. I might install some temp gauges this summer, and experiment with restrictor plates rather then thermostats. On both my engines, the starboard side thermostats were stuck open anyway, and port side were nasty with corrosion.
 
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I'm trying to get my hands on the service records for my engines. I'm starting to think that the thermostats were never changed, the port side got partially stuck shut, lack of flow, build up of salt, and finally corrosion.
 
i can honestly say i didnt even notice the gaskets when i changed them, i did dig out that gray rubber silicone that was inside the grove. After digging it out i put in some high temp liquid gasket in before reseating them. you mentioned that there was a metal backing on the gasket . i'm assuming that mine must have still been there but i wasn't looking for it . i'm guessing when i pull them back apart i'll notice it.

one other thing you might check out is the main relay , the early ones had a tendency to corrode on the inside until the wires would short. i learned the hard way . Engine died out at sea, then the starter wouldn't stop even with the ignition off, had to shut off batteries to get it to stop then call seatow. The main relay wasn't much $$ and it was an easy fix. not sure if the 05's were affected.
 
i can honestly say i didnt even notice the gaskets when i changed them, i did dig out that gray rubber silicone that was inside the grove. After digging it out i put in some high temp liquid gasket in before reseating them. you mentioned that there was a metal backing on the gasket . i'm assuming that mine must have still been there but i wasn't looking for it . i'm guessing when i pull them back apart i'll notice it.

one other thing you might check out is the main relay , the early ones had a tendency to corrode on the inside until the wires would short. i learned the hard way . Engine died out at sea, then the starter wouldn't stop even with the ignition off, had to shut off batteries to get it to stop then call seatow. The main relay wasn't much $$ and it was an easy fix. not sure if the 05's were affected.

The metal is covered with rubber, to give it form, so you wont see it. You will see what I mean when you get the new ones. I can only describe them as very malleable. They bend easy, and have to be straitend out if things don't go right.
 
Just looked at the service manual again. It says to grease the exhaust guide seals, but no mention of silicone. I wonder if the factory grease solidified to a silicone-like consistancy? That would make sense. Even so, a little high temp silicone wouldn't hurt here, as long as you don't get it on the seal.
 
Jamey,

My t-stat housing corroded the in the exact place yours did. Fired the engine up one day and saw water shooting out of the front of the cowling.

After some crazy, and expensive estimates from several mechanics, I decided to go your route, but I used MarineTex, instead of JB Weld. I cleaned up the area with a Dremel grinder, being careful not to take too much metal out.

My first attempt lasted about 6 hours of run time before a small pin-hole leak developed. Repeated the repair process and I've put 30 hours on it. Starting to see a small hole again, so this time I may try JB Weld.

2002 BF 225 w/ 600 hours when I found the problem. Also had the mid-shaft bearing go at the same time.
 

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Yikes, that looks horrible. I might try some quick steel instead as it is more of a putty. I will post some after pics.

As far as the seals, it is silicone down there, just no mention of it in the service manual.
 
Wholly Cow looks like I have more researching to do on my motors now !!!! When I changed thermostats a month or so back I noticed salt deposits bulidup on inside thermostat housing makes me wonder if this is going on on my... have never replaced internal anodes 1600 hrs
 
For those thermo housing repairs I would try to find the best TIG welding guy around and run it by him to see IF it can be welded. IF is the biggest word here but IF that cast can be welded, it would be a far superior and more permanent fix because a good welder will use filler rod to build up that area and it will be of like metal melted and FUSED into the base as opposed to "glued" to component.

I hope one of you guys gives that a try so we'll all know if it can be done.

Good luck and thanks for the VERY informative thread!
 
Jamey,

My t-stat housing corroded the in the exact place yours did. Fired the engine up one day and saw water shooting out of the front of the cowling.

After some crazy, and expensive estimates from several mechanics, I decided to go your route, but I used MarineTex, instead of JB Weld. I cleaned up the area with a Dremel grinder, being careful not to take too much metal out.

My first attempt lasted about 6 hours of run time before a small pin-hole leak developed. Repeated the repair process and I've put 30 hours on it. Starting to see a small hole again, so this time I may try JB Weld.

2002 BF 225 w/ 600 hours when I found the problem. Also had the mid-shaft bearing go at the same time.

If i'm seeing this right, the corrosion ate away the mounting surface in your case. You may want to try to fabricate an aluminum flange to sandwich between your thermo housing and the block, so the o-ring on the housing has a nice surface to seal to. A machine shop should be able to do that for cheap if you dont have the tools or materials. You could even fab some kind of sleeve to go down there, and protect the whole circumfrence, sort of like sleeving a cylinder. Epoxy the sleeve in there, and back fill the void with some JB weld. Just be sure not to block the water passages.
A good friend of mine, a union welder, stopped by and advised against Tig welding, as he was not sure how the casted aluminum would handle it. I will reach out to the best welder guy in my area and see what he says, but since my case is not so extreme, I'm going the epoxy route for now. Looks like when the engines are tilded back, and lean over to the port side, salt water collects in this area.
 
Jamey,

Most of the Welders I spoke to were reluctant to TIG weld that Aluminum, and one indicated that if the block had been cast with inferior Aluminum, the inferior particules in the block may react adversely with the high heat of the TIG.

So, I went with MarineTex. I'm open to any suggestions on using an alternate patching material.
 
If i'm seeing this right, the corrosion ate away the mounting surface in your case. You may want to try to fabricate an aluminum flange to sandwich between your thermo housing and the block, so the o-ring on the housing has a nice surface to seal to. A machine shop should be able to do that for cheap if you dont have the tools or materials. You could even fab some kind of sleeve to go down there, and protect the whole circumfrence, sort of like sleeving a cylinder. Epoxy the sleeve in there, and back fill the void with some JB weld. Just be sure not to block the water passages.
A good friend of mine, a union welder, stopped by and advised against Tig welding, as he was not sure how the casted aluminum would handle it. I will reach out to the best welder guy in my area and see what he says, but since my case is not so extreme, I'm going the epoxy route for now. Looks like when the engines are tilded back, and lean over to the port side, salt water collects in this area.


Just came across this thread about the thermostat housing corrosion and thought I would throw in my two cents. I agree with the sleeving method to try to fix this issue. I would stay away from anything real stiff/strong like Stainless steel as the expansion / contraction rates of the different metals might cause additional stress cracks in the alum housing after you have epoxied it in place. I was thinking something softer like copper, brass, or aluminum tubing. My 06 225BF has 155hrs, only used in fresh water, flushed after every use and when I did the SB56 this past year I also replaced the thermostats and installed a water pressure gauge. I was very upset with the corrosion already happening in this same area as well as the corrosion on the exhaust pipes. So far I am far from pleased with the quality of this honda outboard.

Currently at 160hrs and have done the following in the past 9 months.
- complete lower unit as one of the teeth on the forward gear came apart. very center of one of the gears teeth. Anybody need a low hour fresh water lower unit in need of a gear? No other damage.
- seals on the power trim (not tilt) rams are leaking bad
- SB56 performed by me as I was out of warranty when I found out about it.
- poor fit of port side lower cowling seal allowing water to enter engine area, causing rust on non Stainless steel bolts (never see use of common zinc plated fastners on an outboard before this one), this includes the infamous VST drain screw. Got lucky and caught it before it became corroded in place.
- who designs anodes to not be easily replaceable!! (like inside the exhaust manifolds). Heck my water heater at home has externally replacable anodes. Why couldn't honda have done this.
- had to install a hydro jack plate on my pontoon boat as part of the SB56 fix to get the exhaust ports at least 6 inches out of the water when I come off plane.IMG_0153_small.jpgIMG_0175_small.jpgIMG_0178_small.jpgIMG_0284_small.jpgIMG_0302_small.jpg
 

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Shocking that you have the same corrosion, in FRESH water.
After I found the damaged extension cases from the blown vertical shaft bushings, I wrote a nice letter, 2 pages, along with pictures and $6000 worth of service records from the local Honda authorized dealer since the engines were installed new. Honda's answer "Sorry, there is nothing we can do, you must have an electrolosys problem at your marina. Also we noticed you never changed the water pumps." I told the lady that the dealer never sugested changing the water pumps when they serviced the motors every year, even though the water pumps have NOTHING to do with it, AND the ones I pulled out have no wear on them. Answer "Sorry, there is nothing we can do."
Thanks Honda!
I can't wait for the next time someone asks me how I feel about my Honda outboards next time at the dock.

As a side note, I probably have about 10 hours so far this season on my engines, a couple of high RPM trips offshore, the seals I did not replace seem fine, and no issues running without the shaft bushings either. Got my fingers crossed.
 
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