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Honda BF225 Corrosion

iang6766 said:
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.
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Thank you for the quick replies, I thought about trying to get the water up thru the power head as you mentioned, but these motors only have a skinny water hose line I believe, not a tube like my old evinrudes had. I'm heading out now to pull the LU and have a look. Thanks
 
Ok, found the leak pretty quick. There is a hole in a horizontal ledge at the base of the block behind the vapor separator. The water is shooting straight up onto the bottom of a plug I believe is the oil pressure switch. I think I've seen a photo in one of the threads on here that may be identical to my situation. It started raining again, so I had to cover up and stop. Well at least I found the hole. I'll see if I can find that photo, I've read of a few guys repairing holes. Also the inside walls of my t stat holes have pretty serious "cavities" eaten in them. Would it be wise to attempt to fill and smooth these? Thanks Mark
 
I hate so say this but if you want a proper fix you need a new short motor, in my experience, and I have seen a few of these, you will find a number of places in the water jackets where there is extensive electrolysis. It usually has something to do with where the boat was moored, or even worse, could be to do with wiring or shore power causing stray current in the water.Given that you have water in the oil too tells me there is another internal issue corrosion wise. The hole you describe will not cause milky oil. Also, the fact that there are no thermostats probably tells you there have been overheat issues in the past.
 
You will have to pull a head off to inspect the hole, so you can inspect the water jacket around the cylinders at the same time and make a decision then
 
Thanks iang, i think I'll be able to have a good view of the hole with the vapor separator removed. What a bummer, I only put about 5 hrs on these, and the other motor could be just as bad. Do you think I should do a compression test or go and pull heads based on all the corrosion seen so far?
 
If it was mine I would pull the heads off for the sake of s few gaskets, simply because I would want to know the condition of the inside, after all, these engines are 13 years old and lived in saltwater
 
Got back to work on it today. I removed the whole vapor separator assembly and the fuel rails and injectors. I have pretty good access now to the hole for patching. I was hoping to get the injector bases off to have even more access and a good look around the head gaskets, but I don’t believe there is enough clearance to get them off without pulling them with the heads. I believe the water got into the oil through the intake manifold having water squirting all around it. That gasket was really caked with salt as are the faces of the injector bases. There was also a water oil mix in the bottom of the intake cover when I removed it. So as my spark plugs all looked good and the motor ran well, I’m thinking of doing the patch and clean up the mangold and new gasket and oil, check compression, and run it again. Really don’t want to pull the heads if it’s not necessary. What do you think?
 
The compression will not fix itself, pull the head off since you are this far, it will have to come off anyway to fix the issue.
 
Is anyone familiar how the oil tubes are held into the lower case? I noticed my port side tube has some cracking around the base. I’m wondering if the water that was gushing inside the cowlings could’ve gotten sucked in through the base of the tube. I’m assuming there is oil pressure in there while running?

Thanks, Mark
 
The oil tubes are pushed in like a grommet, there is no oil pressure, the oil simply drains back into the oil pan from the rocker covers
 
Update: I got the hole repaired nicely with jb weld. The oil tubes were definitely letting the spraying water to get down into the oil. I replaced them and put some Honda bond around the barbed seals. Also cleaned up the intake manifold and replaced the gasket, filled the cavities in the thermostat housings and added new t stats and o rings, new oil and filter, and new plugs. Checked first with a hose up the water tube and no leaks, then fired it up, all good. No leaks, and oil looked pristine. After meticulously cleaning everything and refitting the lower unit, I ran it again on muffs and got an overheat alarm after a few minutes. It did have a good pee stream. I've read that these motors don't run well on muffs, so I got my big plastic barrel and ran it again in the barrel with the water flowing. It took a while to alarm again, but I could get the temp back down by just slightly increasing the rpms. I could see my temp readings decrease and rise with the throttle position. It definitely didn't like the low idle at neutral (9k on my gauge) but was perfect at 10k. Checked and adjusted the throttle cables to try and keep the idle in neutral at the 10k happy place. I still had the plastic upper air intake off and the cables in an upward arch. I could get the rpms to fluctuate by just moving the cables. Do they need to be secured in place when adjusting? All my cable measurements seem to be on according to the manual.
 
It definitely didn't like the low idle at neutral (9k on my gauge) but was perfect at 10k.
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Do you mean 900rpm and 1000rpm? If so I think that the factory idle should be around 750rpm - so something's a little out of whack there.

What do you mean by 'didn't like the low idle'? Running rough or overheating? I've run my 07 engine with 900 hours at idle for well over 30 mins in a 700L tank of water (that's gradually getting warmed by the engine) without throwing an overheat error.
 
Glad the repair is looking good.

Yes, throttle cables should be secured in place when adjusting. At least, that's my understanding.

Spec RPM's on the BF 225 are 650 +/- 50. That's where you should be. Anything much higher will cause a hard shift and wear the lower unit gears.

Are you sure your RPM gauge is set correctly and reading correctly?
 
Yes sorry, thanks. The manual says 650+/-50. It also just sounds low at neutral, not sure how accurate the guage really is, it a flowscan replacement. If I just advance the throttle roller at the engine or from the binnacle a touch it sounds perfect and the temp stabilizes. I was thinking I would be able to tweak the cables, and not need to touch the idle adjustment screw? Note, that I just purchased this end of last season, and discovered it had been running without thermostats for who knows how long. If my cables and measurements are good, is it simply an idle screw adjustment? I'm running in a barrel with the prop on, and the water continually flowing. Thanks
 
You don't adjust idle with cables or throttle stop screw, that is preset by manufacturer. There should be a small amount of free play in the throttle cables at idle to make sure the throttle is seated against throttle stop. Idle is adjusted by warming up the engine, disconnect the IAC valve (alarm will start beeping, this is normal) and adjust idle to 650-700RPM using the air screw on top of the throttle body. You do not want the idle faster than that as Chawk said or you'll have difficulty shifting out of gear into neutral.Once idle is set, reconnect the IAC, and then use the shunt to cancel the logged fault. If you are getting an overheat at that speed you have a water pressure issue, try it out in the water before ripping into things, it just may not be getting sufficient water using the method you described.
 
Thanks guys, I have the cables adjusted perfectly now. I had the one just a bit too tight which wouldn’t let the throttle return against the stop screw. I took off and cleaned the IAC screen and the lower exhaust manifold tubes. It ran and idled very nicely, (in a raised sideways barrel with the hose constantly running) but still would overheat and alarm unless I bumped up the rpms to 900.
I pulled the LU off again and fit the hose back up into the water tube, ran it again, and it ran and idled PERFECTLY at 650-700 with steady temps at every point. I figured I’d have to find something wrong with the water pump. It looked pretty much brand new, the only thing I noticed was the inside of the driveshaft hole in the plastic housing above the impeller cup was a bit melted. The shaft has no play at all, so I’m not sure what caused that. I also found the small black barbed nipple had a crack just below where the tube slips on. It seemed to have good flow at the pisser running in the barrel, but obviously not like the super stream from the hose up the water tube. Any suggestions besides another water pump and new barbed nipple? Thanks.
 
Replace the complete water pump, if there is signs of melting it has run dry at some point a d the liner will not be sitting true giving low water pressure at low rpm
 
Thanks iang, that’s the plan. Can you tell me what that nipple and tube from the LU is called? I can’t find any reference to it in the manual anywhere. It leads to a small hole in the leading rounded face of the gear case.
 
So I replaced the water pump housing and gasket, put LU back on, back in the barrel, and she idles perfectly at 650 with a strong stream at 138-141 degrees after 10 minutes. Looks like I may finally get this thing in the water this season. Thank you iang and others for your advice along the way, much appreciated.
 
Great info in this thread! Thanks for sharing all the details as it is very helpful to me now a couple years later as I tear i to a similar problem with my milky oil 225��
 
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