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2006 BF150 Water in oil

J

jdh_ki

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I've got a pair of 2006 BF150's with 1800 hours and one of them recently started running rough and dropping rpms at speed. Dipstick shows water intrusion and cylinder 3 spark plug is rust colored. Compression test reads 205-195-175-200. Prepared to do a leakdown, but is that really going to tell me anything I don't already know? I'm assuming I've got a blown head gasket or corroded head and in either case, I've been advised that it's really not worth repairing by a long-time Honda mechanic. Really not wanting to repower now, but I don't want to waste my time and effort chasing a lost cause. Could this be anything other than gasket or head corrosion? Is one more likely than the other? If head gasket, how many have had success just slapping another gasket on and sending it (not going to put anymore $$ into than that)? Thanks!
 
Hi,
I don't have any experience pulling heads on these but my opinion is if you don't at least take a look, you'll never know. That would always bug the $&!t outta ME!

Plus, just the fact you seem to have caught this early and no overheating occurred, I would guess that there's a very good chance that it can be repaired with a head gasket.

I don't know how access is but you might want to pull the t-stat cover and look to see if there's bad corrosion in there. That could possibly clue you as to where to go next.

Good luck.
 
jdh_ki said:
I've got a pair of 2006 BF150's with 1800 hours and one of them recently started running rough and dropping rpms at speed. Dipstick shows water intrusion and cylinder 3 spark plug is rust colored. Compression test reads 205-195-175-200. Prepared to do a leakdown, but is that really going to tell me anything I don't already know? I'm assuming I've got a blown head gasket or corroded head and in either case, I've been advised that it's really not worth repairing by a long-time Honda mechanic. Really not wanting to repower now, but I don't want to waste my time and effort chasing a lost cause. Could this be anything other than gasket or head corrosion? Is one more likely than the other? If head gasket, how many have had success just slapping another gasket on and sending it (not going to put anymore $$ into than that)? Thanks!
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I've bought more cheap motors this way. Sold to me for parts, because people have been told their motors "aren't worth fixing" by some "expert". My belief is that these "mechanics" are either incompetent, or they're trying to sell you new motors to save themselves the trouble of fixing yours.

I don't have any BF150 experience, mostly because I work at a hobby level and generally have all the work I can handle (and then some usually) working only on the 40-90hp motors - without having to handle the size and weight of the bigger motors.

I've done dozens of the smaller engines with the "water mixing with oil syndrome" and my success rate is nearly 100%. Sure, there were some that needed blocks, short blocks and heads. I don't consider that an insurmountable issue when considering what these motors cost to replace. Those parts are all available on the used market (try e-bay), and even when figuring something like that in, make for a pretty reasonably priced repair - assuming you have the time, the place, and the patience to do this work yourself. MOST of my repairs involve only a gasket set, and some patience to do the job right.

I think you are spot on with your diagnosis, and there's little doubt how I would proceed. My thoughts anyway, FWIW. -Al
 
I'm with these other responders. As JGMO said, pull the head and see what you are dealing with. The Honda BF150 was and is one of Honda's best marine engines. If there is no significant corrosion, then go with just the head gasket. If there is significant corrosion, and the rest of the engine is in good shape, you are still much better off with a rebuilt head, which should give you another 1000 hours at least. A new head on Boats.net is about $1300. A good rebuilt one should be in the $800 range.
 
This is what I just started going thru. I have little over 800 hours on 2009 BF150. My cylinder number 4 got water last time out and oil was milky as can be. Just pulled the head and it’s got holes on the exhaust side of the head. That being said I’m about to order parts which erroring on the side of caution should be about 2k. I have twins so buying two new engines at 15-18k each is not an option at this time. I broke the whole thing down myself following the manual. Doesn’t seem like all that hard of a repair. U will need to get a couple special tools. Now I have never rebuilt a 4 stroke but have put an Optimax back together once. I’ll post some results once I get it going back
 
I have had the milkey oil on four BF150s couple 2004 275 hours and couple 2007 engines 800 hours. The years make the engines differant, differant chain cases and wiring harnesses. Getting the pullyweel off without the 55MM socket holder is bit of a challange since the crank bolt holding it is torqued on at almost 200. I would drain the milky oil, drop lower unit and run engine with cheapest walmart oil using no water muffs or flush to cool it. Do this for 20-30 seconds at a time let it cool between runs then drain that out otherwise some of the internals will rust. Then start process of disassembly.
On the four engines all had pin holes in the heads. one also had barrel corrosion up to the cylinder liner and head gasket not able to salvage that one. welding heads will only last maybe get 100hours and it will blow out or rot somewhere else. So I buy the complete head with valve assembly part and new head gasket. I have each time reused the head bolts but torqued to the book spec for reused bolts. If you find a freshwater head that needs to be redone the intake exhaust valves and springs are colored pink and black and need to go to the correct side. Had a machine shop do valve seat and deck head and he got mixed up and had to show him what valve spring when where. I have two engines worth of parts if needed anything can send out at 25% of boats.net price plus shipping so if you drop a cam and it shatters I have them. I also have a running BF150 test engine on engine run stand and can test any part you think is not right. After you get it together and running for short bit the change out oil.
 
Your compression reading are too high to have bad head. the rust colored spark plug thru me off. Do you have actual rust on the plug or is the ceramic a rust color? Additives might cause the color change. I had a bad chain case gasket below the thermosates that will leak water into the engine. I would definatly pull the the timing chain cover below the pulley wheel and look for corrosion there first.
 
A hole in the head the engine will run like crap or not at all if you have a bad head and you will defialty get water on a plug, you can even see the water shooting out the spark plug hole when turning it over. When you pulled each spark plug did you see a droplet of water on any that would mean a pinhole? if engine still running good the oil is likley coming in below the thermostate housing
 
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