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Here we are again.....BF150 Overheat again?

J

jdepdawg

Member
Hello again, i've been dealing with this issue for a few years now....Ya'll have done me alot of help and provided expert guidance. I apologize that I have to ask for assistance again.

I've posted about this before and it seems the trouble stops - but then starts again. IT's back

My 2011 BF150 mounted on a 21 foot Hurricane gave me an overheat alarm again yesterday....it idled down and i shut it off. I look at the Garmin (NMEA2000) and it was reading 175 on the engine gauge - the overheat warning horn sounded sustained tone. I let it sit for a few minutes and checked to make sure had nothing plugging the intakes - and they were clear. the boat was running 5000 rpm for about 30 minutes prior. After a few minutes - fired the boat up and ran 20 minutes home - no more warnings or events. Gauge stayed right at 175 for the ride home

When i first started having these issues in 2015, i replaced the thermostats, impeller and initially thought faulty. I then took it to a dealer and he cleaned the relief valve that HONDADUDE suggested. Last year, i put new impeller in and again the horn sounded overheat. but gauges all said 175 - ir heat gun on head was 160. Couldnt duplicate.

This year, i got a check engine light and dealer couldnt decide if it was a OVERHEAT or O2 sensor issue - they said they had a history code of an over heat and i provided them the date that occurred. they kept the boat several days and they said the Honda Factor Tech helped them decipher whatever issue it was and they replaced the o2 sensor and i had them put a new impeller and kit in as well as the 200 hour service. and relived my wallet of 1000.00 dollars.(dealer is a honda dealer) I ran the boat about a week after i got it back and no issues.

It's not been 1.1 hours since i got the boat back from the dealer with the new impeller and o2 sensor and i got the alarm yesterday.

I will be buying new thermostats again,(Relatively inexpensive) as the ones i have are now going on 2 years ......but in the BF150 model, i see there are ECT sensors. I am not positive-but i think there are a total of 4 ECT sensors in the engine - I have no idea which it could be or how you could determine -

Can this issue be those sensors going bad? - i can't find much about these sensors and i how to swap them out yet? and has anyone had anything similar?

I dont really have a clue what else it could be -
New impeller and kit
New spark plugs
New 02 Sensor
All done 1.1 hour ago.....

Thoughts or recommendation from anyone???

Enjoy your holiday - I wont be on the water until i get this figured out.

thanks again for all your help
jeff
 
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Hi jdepdawg,

Well.......I think you are on the right track. I don't know this outboard nor do I have any documentation for it. But, based on the gauge readings and what you are seeing with the IR thermometer, I don't think the engine is overheating.

My guess is that the overtemp alarm shouldn't be activated by anything but an engine temp of 200 degrees or better. Most engines can easily withstand 230 degrees with absolutely no harm even though most will be set to alarm in a range somewhat just under that.

So, your theory of one or more faulty senders is likely to be correct.
In addition to that, I'm completely baffled as to why the dealer shop would not have already considered the possibility and tested the sensors. With the experience you've had with the alarm going off and Tstats and pumps being replaced AND charging you $1K for the LATEST work......the words incompetence and dereliction come to mind. That is, of course, if I'm not missing something in your story.

At any rate, it is MY OPINION that any and all sensors conneceted to that overheat alarm should be tested and/or replaced and it is MY OPINION that it should have already been done.

I'm sorry I don't have the info needed to aid you in locating them and testing them. But if that dealer won't take the outboard back and do it for you NO CHARGE, they should at least help you with doing it yourself.

P.S. there are two temp senders in the exhaust manifolds right next to each thermostat.
See items 14 (×2) next to tstats, items 11 (×2) in the link below.

www.boats.net/parts/search/Honda/Ou...K1 XCA/EXHAUST MANIFOLD THERMOSTAT/parts.html

The link below is (hopefully) a close-up illustration of the senders. It looks like you'll have to copy and paste in your browser to open the link.

35673-ZY3-003 SENSOR, WATER TEMP (Honda Code 6991889)

There is another temp sender located in the engine block UNDERNEATH the intake manifold. See item 25 in the link below.

http://www.boats.net/parts/search/H... Later/BF200AK1 XCA/CYLINDER BLOCK/parts.html

That one is going to be "major surgery" to get to. But, the other two look to be relatively easy.

Find those two on your outboard and let me know how many wires go to each sender. If it's only 1 wire or 2 wires I can give you an idea of how to test them.


Good luck.
 
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Thank you for your reply and your advice. The dealer is trying to schedule a time to come do a ride on the boat with me and see if we can dupe the problem - he will bring a temp gauge with him - just not sure when/how soon he will be able to come up here......I'm waiting with a positive attitude - I think the two sensor's up near the t-stats will be the first to swap and replace - they are pretty darn cheap........but I'm just going to wait and see what the dealer says.......

Any other advice??
 
I was looking at the 200hp V-6. Your 150 being a 4 cyl. Is going to make things much simpler. There are only two coolant sensors....one in the block (see item 15 in the link below)



http://www.boats.net/parts/search/H...d Later/BF150AK2 LA/CYLINDER BLOCK/parts.html

And one in the exhaust manifold (item 7 in the link below).

Both of them look to be accessible but that might not be the case at all.

Still it looks to be a much better proposal than the V-6

Hopefully you will get taken care of at the dealer and not just taken.

Sorry about my confusion but hopefully it's not contagious.

Good luck.

http://www.boats.net/parts/search/H...Later/BF150AK2 LA/EXHAUST MANIFOLD/parts.html
 
Yes! You are correct, I completely missed those! Good thing you're paying attention:>).

One of the other two is item 17 in the link below. It is installed in the side of the block.

http://www.boats.net/parts/search/H... Later/BF150AK0 XCA/CYLINDER BLOCK/parts.html

The other one is in the exhaust manifold....item 8 in the link below.

I hope that's correct now! Sorry for MY confusion! Good catch on your part. I guess I should slow down a scosh when offering advice on an outboard I've never actually seen.

Good luck.


http://www.boats.net/parts/search/H...nd Later/BF150AK0 XCA/EXHAUST PIPE/parts.html
 
I took the boat out again today - 2000 rpm through the no-wake zone of 3/4 mile - then throttle up and ran 2 miles at 5000 rpm......slowed down and went into idle mode so I can find a fishing spot.....I fished for an hour at idle speed - in neutral - moving the boat back to the hole and idled more......then ran boat home total about 1.5 hours running...............no issues - no overheats....no nothings......I looked at temps and never went above 175....felt the tell-tale water it wasn't even hot.....

HONDADUDE or CHAWK - what are your thought on this?
 
i ran the boat again today - for about 1.5 hours - no overheat - - is it possible, at low speed that the water intake in the lower unit picks up more water and when running with motor trimmed up - it's not getting enough water? seems to only overheat when running on plane.....or could it be the t-stats not working properly when higher rpms
 
Yes! That is a great question and the answer has to be in the affirmative.......in general.

I mean, it's absolutely a possibility that an outboard's mounting and trim setting, along with hull design and who knows how many other dynamics, could be such that the water intake gets "starved" while on plane. But it would be foolish to assume that is what is happening.

I'm not an accomplished and experienced individual when it comes to "pairings" of boat hulls and power units. All I know is that the outboard is typically mounted to a boat so that the cavitation plate is pretty much in line with the keel and at the same depth....if at all possible.

But I also see all sorts of "techniques" used.... like jack plates and transom extenders..... to position outboards for, ostensibly, better performance and maneuverability.

I also think most of us understand that for conventional mounting , for different reasons, this can't always be done exactly and things get "fudged". It sure is something I would look hard at in a case like this along with what your load is and how it's arranged in the hull.

Getting more water to the pump could be as simple as repositioning some gear and or passengers. Or, it could get a bit more complicated.

So look to how your hull and outboard are connected to one another. You said it was fine for a time so look for and think about anything that may have changed from when it was operating normally. You may have shifted some stuff around inside so just putting it back where it was before might help.

Good luck and I hope some others weigh in with ideas.
 
To expand a little on Jimmy's post - the general rule is that the (anti) cavitation plate should be even with the lowest point on the transom. For mono-hull boats, that is usually the keel at the transom. However, for every foot of offset (say, with a motor extender), raise the anti-cavitation plate 1 inch.

Have you removed the screens on the leg and checked for clogging or debris under the screen?

BTW - Honda dude is the expert on the 150's. I don't know much about them. I do believe the the t-stats on that engine have different opening temperatures. Is it possible that they were reversed?
 
Chawk - thanks for the reply - yes sir - I've checked the screens - I replaced the T-stats - they do have different temps and you have to be sure you put them in the proper place - I did them one at a time to prevent confusion.

I've done most everything I know to do. I thought of the motor may be trimmed to much but it was just a thought....hope Honda dude chimes in
 
I guess I'm beyond my level of competence at this point. You probably need to check your heat sensors. Whenever, I dig into the sensors, the first thing I check are the connecting plugs to make sure they are clean and make a tight connection, then I check the wires for too much resistance and make sure they are in good shape - no breaks or bare wires. Resistance should be very close to zero ohms.
 
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