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BF225 flushng procedure, and internal engine anode

Brian silk

Brian silk

Regular Contributor
Can anyone tell me how much pressure to use when using the fresh water flush attachment, and whether it does get into the thermostat housing. I have contacted the tech department at Honda Canada, but you can't talk to a tech, only ask the receptionist and she asks the tech and she comes back with some stupid answer that is of no help at all.

I found that when I flush it with enough pressure to get a decent tell tale stream the top of the water jacket does not cool down unless I tilt the engine up, and there does not seem to be any cold water going through the rubber 90 deg. hoses to the thermostat housing. The water running out the tell tale is cold, until you turn the water off and then it drains out warm, as if there is an area that does not flush. I heard somewher that there is a pressure bypass spring that lets the flush water bypass the thermostat. Is that true? Am I not using enough pressure to get the water to open the bypass if there is one? I did not want to use too musg pressure as the flush hose is smaller i.d and only held on by a spring clip, or too much oressure for elsewhere in the engine.

I flush and and use Saltaway after every use(salt water boat) , but I find that the two thermostat changes that I have done showed more salty buildup in the housing than I would have thought.

Also, the internal anode in the engine, I did not find it in the shop manual, anyone have some pictures. And at how many hours should it be changed?


To those members that helped me with the rough starting issue-the followup. It seemed to go away on its own. However, I changed the high pressure filter on the weekend and it starts even smoother now. I may have also had some bad gas, as I have been gassing up at the First Nations gas dock for the last few tanks. It occured to me that the guy is always asleep as there are no other customers. Maybe their gas is a bit stale.
 
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Ditto on the Saltaway: I have been very disappointed with it. My engines are not the same as yours so I can't help with your other questions. Stan
 
It may be white powder that you see , but is it salt or aluminum oxide ( corrosion ) ??? For iron it is called rust ( ferrous oxide ) for aluminum it is aluminum oxide.
 
Racer, it is more like a crusty scale like a mineral deposit. Powdery when scraped off. maybe a1.5 mm thick, just in the housing below the thermostat. It is not excessive, to the point where flow would be restricted, but I thought it would have been cleaner. Ant ideas on the flush flow/pressure, and whether it should flow through the thermo housing?
 
Brian,

You raise an interesting question about the back flushing. I'll look at the water circulation chart in my shop manual later today and try to figure it out. But, I do not believe that the back flushing gets to the thermostats. My engine has always done the same as yours - the flush water is cool coming out of the indicator, and when turned off, it runs out warm. Frankly, I'm not sure just how much good the back flushing does on this engine. I've had one of the good tech's at my dealer tell me he didn't think it helped much of anything, but I still back flush after every use.

As for an internal anode - I've never found any mention of it in any of the manuals.
 
Brian,

My '02 225 corroded thru the block right under my T-stat. I've got a thread on here w/ pics but make sure you take a good look,esp at the port side of the motor. Ditto on the internal zincs, no mention in the manual, so silly me I didn't assume they were in there or needed changing. (always had 2 strokes). I also have the corroded mid-section issue. I am getting close to pulling it apart and tackling these issues.I will make sure to post pics. My motor only has 600 hours and was flushed regularly. Always ran like a top,BTW
 
I checked my shop manual on the water flow. It does not appear that flushing the engine gets fresh water to the thermostats, and it certainly does not go through them. In fact, it seems questionable that the flush water even gets to the internal water passages around the cylinders. Seems like the principal benefit is flushing the passages around the exhaust manifolds.

Next time I pull my thermosatats, I plan to hook up the flush hose and see for myself.
 
Brian
What I used to do do with my 23 ft Sun Runner when we came back from the cottage in Sechelt was on the way home I would relaunch the boat under The Port Mann bridge and run up and down the river for about half an hour, it did help but eventually I still had to replace the exhaust manifolds and thermostat,do you pull your boat out or leave it in all year.
 
I leave it in all year in False Creek in Vancouver. I flush with the hose religiously after every trip. I did crank up the pressure last time and seemed to get the port thermostat housing cold indicating that it got water flow. This is with the engine tilted up turned to port to let the engine harness hose clear the transom. The starboard side did not get cold though. Also I find that the cold flushing water does not go as far up the water jacket when the engine is tilted down. Maybe the tilting helps to stopthe water from just running down hill?

Does anyone know if it would be feasable to attach muffs with engine in the water and run it. Do you think the fresh water pressure would overcome the saltwater pressure? I believe that there are also a couple of small aux. intake holes in the side of the gearcase, so the saltwater might go in those rendering the exercise useless. Anyone have any ideas?
 
I believe the only water intake is at the two vents on the side of the lower unit. However, because of the many outlets, muffs do not do a good job of flushing the engine unless the out flow ports are taped up and all the flush water is forced out of the exhaust ports around the prop hub. Bottom line - using fresh water muffs while the boat is sitting in saltwater is not likely to do much good.
 
I really dont want to de-rail this thread.....

Does the water flow during the muff-flushing in the Bf150 follow simular passages (avoiding the thermostat) as the 225?

If people dont say how much we appreciate what knowledge you folks pass along, then let me be one of many to say thank you.
 
If you muff flush the water passes through the same passages as normal, as the intake is the same as when the engine is running.
 
chawk_man said:
I checked my shop manual on the water flow. It does not appear that flushing the engine gets fresh water to the thermostats, and it certainly does not go through them. In fact, it seems questionable that the flush water even gets to the internal water passages around the cylinders. Seems like the principal benefit is flushing the passages around the exhaust manifolds.

Next time I pull my thermosatats, I plan to hook up the flush hose and see for myself.
Click to expand...

Is this the same for the BF150?
 
Chalk, in my last post I stated that I really cranked up the hose on the flush and it did get the port themostat housing very cold, but not the starboard. The engine was tilted up, anfd to the port. So, maybe it does, but why not the starboard high side???? I am going to try Honda Canada again and |I will let you know.
 
This is a good thread to follow. My local Honda dealer told me I should be using the muffs all the time instead of the built in flusher. He said the built in system just does not get the job done. If that is the case, why install it in the first place.
 
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