Honda BF225 Corrosion

Now I see the disconnect. The phrase "Water shooting out under the cowling all over the place." was from the originator of thread back in 2017. Being new to forum, I thought it appropriate to continue adding this thread since I thought I had a corrosion issue as well. I think you may have misinterpreted Tom L's symptoms as mine.

In any event, my original symptoms are as follows from my 3/19/19 post: "The engine oil is a murky beige. Cylinder #6 failed a leak down test and after an endoscope inspection of the cylinder, I can see drops of the nasty water/oil sludge on the piston. Is it just the block that is likely leaking [into the oil] or is it the head [corroded] as well?"

Given the 'watery mix' found at the bottom of the intake manifold was a mix of saltwater and motor oil, I'm going on the assumption that it originated from the head/cylinder/headgasket area. I can't fathom how else the motor oil/water mixture found its way into the intake manifold. You can see evidence of the oil in my 5:36 pm post. Your thoughts?

With compression at 40 psi, Im wondering if you have a faulty head gasket. These engines should have 190 psi compression

Okay, apologies about the misunderstanding. Pull the head off and have it pressure tested. The low comp is definitely because of rust on the valve seats and the slight milkyness of the oil will be from water that has passed the rings into the crankcase.

So is there an actual hole in the block?

I would guess a hole in the head, usually in an exhaust port or combustion chamber

Here's the head and block before cleanup. Notice there's a high spot from corrosion to the tune of 0.5 mm both on the right side of the block and a few others on the head in various locations. The corrosive growth noted in yellow circles and buildup of salt crystals where they don't belong leads me to believe that this was a gradual process of slowly lifting the head away from the block, thus inducing the water leakage into areas it doesn't belong.

Here's some pics before cleanup. I'm in the process of doing a valve job after sanding down the high spots on the head (glued sand paper to the flat of my table saw). BTW, I noticed I couldn't get a feeler gauge between the rocker and valve stem.

View attachment 19818View attachment 19819View attachment 19820

Just to be clear, there never was any leakage of water, oil, intake air, or exhaust into outside world that would have been captured under the cowling. I originally became suspect when it started bogging down bad upon going full throttle to get out of the hole, something it had never done before. Panic set in when I got home and checked the oil.

After pricing new Suzuki and Yamaha, I decided to start digging in. $26K has a way of motivating me.

Given the new pics I posted today, do you still think there's a hole in the head or block between cavities or is the root cause likely leakage beneath the gasket?

It's cleaning up decent, but I'm not sure how aggressive I should be with the thin cylinder walls.

Attachment pictures will not open. Try a different approach.

You posted pics before, try the same method. I would definitely have the head pressure tested and skimmed professionally, not worth taking short cuts to save a dollar, believe me,it doedn't pay.I would be very interested to see the pics and what you're trying to describe

Head after self-flattening and valve job.

After I grind this cancer off, there'll be non-protected metal. What should I seal it with: JB Weld, Epoxy, or something else to keep it from coming back?
And how about a CLR or other aggressive substance to clean out all the corrosive buildup? Can I / should I do it without pulling the rubber impeller off?

I see nothing obvious causing your issue, the salt build up is minimal and indicates good flushing, I have seen far worse . I suggest you still get that head professionally reconditioned, that is not properly flattened off

I'd listen to the cats giving the advice about a machine shop. I have similar issues (see my thread: may have stumbled onto water in my oil...) and just dropped my heads at a local cylinder shop for a reman. Gonna cost ~$700, but it beats "fiddle f**king around with it," as my Dad says. I cleaned them up a bit after watching a dozen Youtube videos and realized I need to pay the fee. $700 + ~$300 in parts (gaskets and such... since she's broken apart) + time = I don't have to repower yet.... I'm still going to pull the lower unit and check the water tube as well as inspect the starboard thermostat housing a little better, but the cylinder shop dude showed me a few spots where there was corrosion that could be where the water was creeping past the head gasket. Not to mention when I was taking the port head off, one side of bolts was easier to break... Sooooo, get a "Bible" to torque everything to Honda specs and listen to the gurus on the site. They won't steer you wrong

I definitely think from those pics that you have a hole corroded through into the exhaust port of No6. I also hate to say, if this was my engine and planned keeping it, the least I would to is re ring the engine, that No 6 will almost definitely have seized compression rings which will result in low compression and possibly high oil consumption.

I think you could be a victim of SB #56

Being I'm a new owner of an old Honda, how do I get a copy of these service bulletins you guys keep referring to? BF225

re ring the engine

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Re-ringing is a whole new ballgame. I really don't want to take the block off and to the a machine shop. I fear I'll never get it reassembled properly, not to mention the time. But I see why you suggest it. Tough call.

And one more question: after the shop does a skim job, can I coat the raw metal on the head surface with a protective coating to slow the corrosion?

There is no protective coating I know of, and make sure you have hat head pressure tested

Chalk has all the service bulletins you need, hopeful he will contribute to his thread

Three-plus one,

There are three that may apply - the most important one is #56. They are too big to upload on this site, so send an e-mail to [email protected] and I will return #56, #70, and #71.

On my 03 BF225, does this 'oil control orifice' need an O-ring if I never took it out? I don't recall finding one on the outside surface when I disassembled and I didn't pull it out the orifice during service. After achieving proper head and block flatness, new gaskets, and torque per the maintenance manual, I'm still mixing water with my oil . Where did I go wrong? FWIW, I did reuse the head bolts but that's the only short cut I took and I'm stumped.

No O ring,just the head gasket, did you have the head pressure tested by an engine reconditioner? I did emphasize the need to do so because there could be a pin hole somewhere that you can't see.

No, I did not have it pressure tested. I'm tempted to buy a new head for $1100 but I'm anxious about moving over the camshaft and getting those seals installed right. I'm also lacking the special tool to hold the camshaft while I remove the nut in the center of timing belt driven pulley. Is there another alternative to fixing this problem? Perhaps a used one?

I can't see why you ask for help, you said you took no shortcuts, well you did in that you didn't have the head checked by a professional. This is a spe******ed job and if you buy a new head you will need to have the valves properly refaced before fitting them.That bottom cylinder is looking a whole lot worse too, and I have no doubt that it will have low compression as well as high oil consumption.To sum up, if a job is worth doing then it's worth doing properly the first time, that is the most cost effective way.

The corrosion looks pretty bad. Im not sure how many cylinders are damaged, but you may consider buying a new oem complete short block for under $3000 and redo your cylinder heads (professionally). I would also replace all the anodes!

Three_plus_One said:

No, I did not have it pressure tested. I'm tempted to buy a new head for $1100 but I'm anxious about moving over the camshaft and getting those seals installed right. I'm also lacking the special tool to hold the camshaft while I remove the nut in the center of timing belt driven pulley. Is there another alternative to fixing this problem? Perhaps a used one?

Click to expand...

I have totally disassembled the heads on my 200. I used a nylon strap, similar to the ones used to remove oil filters. Use an impact, its very easy.

Hey all, first time poster here, great info and knowledge here. I figured I’d continue this thread as I have very similar issues. Hope this is ok. I have new to me, this past fall, a pair of 2006 built BF225s with about 1200 hrs. The boat and motors were well maintained by a friend. During my spring prep after the boat sitting over winter in my driveway in PA, both engines fired up first or second crank. As my starboard engine ran on muffs, I noticed the water pouring out of the lower cowlings. I removed lower cowlings and water appears to be coming from up near the middle upper part of motor. I also checked and found a lot of water in the oil. F me I figure. I pulled plugs and all looked good with good color. I was going to do a compression test then, but thought I might find a hose off or another source of the leak. I have the workshop service and repair manual and decent experience. I drained the oil/water, removed center intake cover and found a bit of the oil/water mix in the bottom left. Removed the intake manifold and found a LOT of salt build up between gasket and base. I still couldn’t tell where the water was coming from. Did some reading here, and then checked into the thermostats. Pulled port side cap and found a lot of corrosion, a crusty o ring, no thermostat. The housing had some deep corrosion around inside diameter, but not through fortunately. The starboard side was better corrosion wise, but no stat installed. That is where I’m at now, and could use some advice. I have some new o rings, and new intake manifold gasket coming tomorrow. I figured I’d scape the salt buildup off, put the new gasket, t stat o rings, and oil in and run it with the top covers off to see if leak is gone, or more visible. The water in the oil has me thinking head gasket, but if it was the port t stat leaking the water may have been sucked into the air intake right by it. Or considering all the salt buildup if found so far, and stage of disassembly should I keep going and remove heads? Thanks in advance, Mark.
Also, thank you a Chawk for the sb’s. My numbers are not affected by #56. They have not had the Ho2 upgrade, and have had the sensors replaced a couple times over the years.

I'll try to answer in more detail over the weekend. BUT, with no thermostats the engine was running too cool, likely the cause of water in the oil.

As for water leak - first thing to do is check water hoses going to VST.

Welcome to the forum. Before you go any further, refit the thermostat covers ( no EFI motor should ever be run without thermostats, as Chalk said ) without the thermostats but leave the intake off. Remove the lower unit and fit a garden hose to the water tube going up to the power head from the water pump. Force water up into the motor and get a flashlight and try and see by looking down behind the inlet manifolds where the water is leaking from, it's a lot easier to do this whilst the intake is off. Let me know what you see.