Honda BF- 15A quits peeing;smokes/steams white out the exhaust....

[jake pogg]

Gentlemen,i'd really appreciate any thoughts on this.I've zero experience with 4-strokes,and this is my work boat+motor,crucial at this very season...(the problem was not apparent in pre-season tank testing;as it's governed in neutral,and makes too big a mess in gear,so didn't wind it up too high...).
Again,at med.to high RPM range the power flat-lines,white smoke/stem increasingly mixed with exhaust,motor sounds...rough...
It's in fresh water now,bought used,originally an aux.kicker in saltwater,reconditioned to whatever extent at a Honda dealer....(i live remotely,400 river-miles from the nearest road,so parts/supplies or even advice is hard to come by...).
Thanks in advance,Jake

 

[ondarvr]

Could be a few of things, Blown head gasket, plugged up water jacket passage ways from salt water, thermostat bad due to salt water or bad water pump.

The motor can overheat and blow the head gasket from any of these issues.

You have a bunch of tools?

 

[jake pogg]

Ondarvr,thanks much,Sir.
Your first suggestion-head gasket-confirms my worst fears/suspicions....
(i'm an idjit to not have a pump-kit on hand,but it'd be too much to hope for,after all,the heat build-up couldn't happen so instantly as to rob the power).
I'm reasonably set with the simpler,mechanical tools,and can borrow some more complex from friends,pullers et c.,i think my main handicap is Fear!
Fear of tearing into a pretty complex little engine,OHV looks like,et c.,et c...All in my VERY dusty,primitive working environment,on the bank of a very silty river...
Thanks again,i'll try to do what needs doing with a spare(an 80-ies vintage Merc 2-cycle),and will try to study up on rebuilding of BF as seasons allow....
(i use these small motors(and smaller boats)for manueverability,i wrangle big drift-logs with them,as they come down the river right after ice run...and the drift's here,started today,so any chance at repairs is now shot).

 

[Sea Rider]

That's a prime example of outboards used as it were a cars that runs on pure krptonite, the green stuff that recirculates throughout all water paths. OB's powerheads needs to be disassembled form time to time and have all water paths be mechanically cleaned. With use/time, warm/cool temp cycles will collect unwanted salt layer formations, crusts that will cancel water capacity to disipate properly heat inside powerhead. OB Will run at a much higher working temp and even overheat.

When that happens, neeed to tear powerhead down, remove cylinder head + exhaust lids, covers and clean to immaculate clean cond all water paths. Install new thermostat, head and exhaust gaskets as well. Will have a new like OB.

If with severe salt accumulation, flushing with fresh water on muffs, barrel even for hours won't do a thing. If salt accumulation is moderate, try Salt Away products on a barrel, if products works as stated OB should cool more properly. Fingers crossed..

Happy Boating

 

[jake pogg]

Sea Rider,thank you,seems like some very solid,sensible advice...(i'm not in salt(though the history of this OB is),but am actually in something also less than healthy-volcanic silt...).
My spare having failed me,i'm forced to do an awful thing,and run my ailing motor,and load it as much as possible too.......For some reason it keeps on going,at low/-er RPM,cooling itself,not mixing any fluids,not flinging oil or nothing untoward....
(Maybe it's not the head-gasket afterall?I've a pump-kit on order,but the shop in town will only deliver to the airline on Monday,meanwhile,the motor must work,and suffer.....hate doing it thataway,but....)

 

[Sea Rider]

Yep, sometimes one buys Pandora Outboards. Happened to me. Bought a mint 2 strokes 15 Evi OB, short time after, OB begun to have overheat cond as you're describing. When OB powerhead was disassembled all water paths were near clogged, owner didn't flush OB with fresh water after use, although he sold the OB with included muffs.

If like reading check : http://forums.iboats.com/forum/gene...ies/inflatables-and-ribs/593663-i-swear/page8
Post 120 down.

According to my experience head gaskets only fails badly with a severe overheat due to lower leg water intake blockages. that could end warpping severely cylinder head which is real bad. Install a new water pump kit and go for a Salt Away rinse on a barrel. Just for the reord, post whatever was found, corrections done and final results.

Happy Boating

 

[jake pogg]

Thanks again,Sir.Taking mental notes of all the advice;after so many years away from the ocean hard to tune the old brain back to salt issues!
I'll read that thread you mention above,thanks,and will be sure to update this as to the effect of a pump-kit,and/or some other sequel...

 

[km1125]

am actually in something also less than healthy-volcanic silt...).

That sounds like a prime recipe for tearing up impellers! Do you have to change them often?

 

[jake pogg]

That sounds like a prime recipe for tearing up impellers! Do you have to change them often?

Oh yes.Every year is often a bit too often,but every 2 may sometimes be insufficient,so better safe et c.,and if some still usable parts come out,well then they could serve in an emergency.....(so it is Utterly daft of me to be caught without a spare;and the pump Was new last year(meaning, nothing,of course,but underlining the above...).

The glacial silt in the Yukon is so thick that it makes an audible hiss against the hull of an aluminum boat......And although the main River is deep,and wide,it has sand/silt bars,and also shallow,rocky tributaries,so carrying 2-3 spare props is not at all uncommon...Often,on long trips,a spare lower unit is great to have on hand.

 

[km1125]

This might be branching into a bit OT, but if this was a normal operation and you're going through that all the time, I'd be exploring converting the engine to a closed cooling system and putting in a keel cooler. It would be quite a modification but it would eliminate the need for raw water impeller changes and the risk of losing cooling on a trip. The keel cooler could also be protected with an actual keel if you were operating in very shallow water (since you've also indicated you go through props too). I'd be thinking of rigging some kind of prop guard too.

This does not address your current issue, but something to think of as a long-term solution if you intend to continue to need to operate that way.

 

[ondarvr]

It's far simpler to change water pumps than to build a keel cooler for an outboard that's going to run in shallow water.

​If actual smoke was coming out of the pee tube then there's a very good chance the head gasket is blown, but if it was just steam puffing out it could be OK.

​Check the compression.

 

[jake pogg]

Km1125,thank you,these are all very sound ideas.
I'm afraid that due to the specifics of local use,most of which are VERY harsh,the maximum simplicity is best...
In this particular seasonal chore,for example,i operate often in what amounts to a Soup of small(and not so small)driftwood....It would skewer the guard,and the prop,hitting now an affixed obstruction,would bind on it ferociously...(i use alloy props,and regularly break the blades off,clear at the very base.....and last year i've managed to break two at once...
This is some rough country,and the equipment is called upon to function well outside it's intended purpose...

I'm entirely puzzled now,as the motor SEEMS to be improving somewhat with use....I'm getting more RPM/smoother curve,too...And the water discharge is steady through the range...
I wonder if i should consider water in the gas....We always run on a Racor water-separator/filter here,it's not even optional,but sometimes the emount of water exceeds the filter capacity....

 

[jake pogg]

Thank you,ondavr,i will,at the earliest opportunity...and when i do,what would be an acceptable number,(besides being even cyl. to cyl),for an older motor?

Also,just in case anyone knows:Last year,in the process of helping someone troubleshoot their Yamaha 4-stroke,i was shown a rather hidden screw,that was essential in draining the water from the fuel system.
Is there a similar,less-than-obvious way to drain the Honda 4-stroke fuel system?

 

[jake pogg]

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P.S. Here's a photo i just took of someone else gathering drift-logs.It's not a close-up of the surface,but it,and for some few feet under,is thick with smaller sticks...