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  1. #1
    Join Date
    Mar 2013
    Location
    Merritt Island FL
    Posts
    49

    Default Honda BF150 overheat alarm

    I searched and could not find an answer here - so i'll throw this to the experts.

    Boat is run in salt water only.........impeller is less than year old.

    two days ago, i lowered boat into the water and started the boat. While it was idling, i ran into the house to get something - i heard the overheat alarm go off. It has never done that before. It's got 160 hours on it 2011 model year.

    I went out to the boat and the motor had shut off. I restarted the boat, no issues, and idled in the no-wake sone for about .2 of an hour. I have a NMEA2000 set up on my Garmin 441S and looked at the engine gauges. I noticed the the temp gauge creeping up... I watched the gauge get to about 180 and the alarm kicked in - so i shut the boat down.

    I then watched the gauge and it went down fairly quickly - so i started the motor back up - i made it out to the deep water and went up to 5000 rpm. The alarm went off after a few minutes and the gauge said 180 degrees. I went down to idle, the alarm shut off and the gauge remained right around 175-180 - no alarm.

    While idling - i went a felt the water coming out the pee-hole - good strong stream, not hot, but not cold either.

    I idled about 10 minutes and got boat home, no issues.

    I went to the local honda shop and spoke with the guy at the parts counter, i couldnt talk to a mechanic. The parts person was briefed on what occurred and impeller age. He thought could be the thermostats. I bought two new ones, and gasket.

    Yesterday, started boat up - no issues - after .5 hours, of high rpm 5000, i watched the gauge finally get up to 180'ish and the overheat alarm activated. I reduced to idle and went home to put in the new thermostats. I confirmed the over heat alarm and looked at the warning light, the green oil pressure light was glowing green - and the red temp light was on - also, the GPS NMEA said OVERHEAT WARNING #1 (only have 1 engine)

    I removed the thermostat cover, there was some corrosion on the old thermostats, and little in the housing. I cleaned up the housing - and installed new ones and replaced the cover. Checked for leaks, all was good.

    Took boat out - and watched the gauges - i saw the temp gauge on the GPS come up to 150 - then creeping up a little more, then it stayed at 175 for a long while - i started to do 5000 rpm's to see what was going to happen - the peehole was streaming good, temp of water coming from peehole was same as before - not hot - but not cold.

    I kept doing the 5000 rpms for about 30 minutes and i watched the temp gauge creep up to over 200 - no alarms, no red lights no warnings -
    I slowed to idle - and the temp went down between 175 and 200 and i idled home - not knowing what the heck was going on. I shut down the motor, turn the key to on position and got the normal two beeps -so the alarm horn works

    I dont know what temp the boat should run at - but i dont think it should be running at 200 degrees - i've heard you can cook a motor that hot.

    I have not dropped the lower unit to check the impeller - it seems fine based on the peehole stream being fairly strong at idle and at higher rpms.

    Any suggestions on what it could be or what i should look for??

    Thanks in advance for your assistance
    jeff

  2. #2
    Join Date
    Sep 2008
    Location
    Hague, Virginia, USA
    Posts
    3,733

    Default Re: Honda BF150 overheat alarm

    Honda Dude is the 150 expert on this forum, so hopefully he will chime in.

    That engine should not be running at 200 degrees F. Why you did not get an alarm is a second issue that you need to address.

    However, if this happened to my 225, the first thing I would do is check the oil level.


    The second thing I would do is pull the covers off of the intakes on the bottom of the lower unit and make sure they are not clogged up.


    The third thing I would do is pull the t-stats, and back flush the engine with a garden hose. Use a fine-textured rag to seal the garden hose into the openings as best as possible and put a bucket under the lower unit to see if you flush out any debris.
    CHawk 25 DLX

  3. #3
    Join Date
    Mar 2009
    Location
    Cincinnati, OH USA
    Posts
    4,176

    Default Re: Honda BF150 overheat alarm

    Do all that chawk said and....

    Check to be sure that you put the higher temperature thermostat in the block.

    ....also check your relief valve.....#15 http://www.boats.net/parts/search/Ho...ASE/parts.html

    It may be clogged.

    Temperature of the block should be around 158 deg F. Temperature of the head should be around 140 deg F.

    The piss stream will generally stay cool, since it is "T'd" off at the base of the powerhead, before it has a chance to get warmed up by the engine.

    Although I have not installed anything with NMEA 2000, I will be doing so on a couple of 150's within the month. I have been looking into what is provided by the engine. Unfortunately, the output that Honda gives you on NMEA is not the same temperature that tells the ECM that the engine is overheating. The Honda output to NMEA is higher than the temperatures that you would expect.

    I do not know if you watched it, when all was "normal", but, from what I understand, it will be higher than the 158 degrees......kind of misleading.

    I suggested checking the bypass, since it seems that you stay within temperature range when going slow. When you open it up, the exhaust pressure opens up the relief valve and dumps more water out, increasing the cooling ability.

    Mike

  4. #4
    Join Date
    Mar 2013
    Location
    Merritt Island FL
    Posts
    49

    Default Re: Honda BF150 overheat alarm

    Gents, Thank you for the responses. Chawk-Man, I did check the oil, when cool, it's right beneath the upper dot on the dipstick, after running and being warm, the oil level is about 1/4 inch below the dot - it's near the upper two thirds of the space between the low level and max level on dipstick.

    Mike, this relief valve #15 - i will look for that tonight or tomorrow - when i have a few minutes. I plan on using an IR gun and hit the cylinder to see temp,

    Question - last night - i tinkered with it, but couldnt get into the mood to actually do anything.....i did check tho, the two beeps actuate and sound off when you turn the key on - but i thought it was strange that when that nmea temp gauge said 200 degrees, i did not get a sounding. that was bizarre in my opinion. But who knows.....i am wondering if when i got the alarm the first time, at about 180, since i shut down as soon as alarm sounded, it cooled enough. When the alarm sounded 2nd time, again, i shut down and idled. The temp on the GPS was near 180'ish. But i shut down and slowed each time and the alarm ceased sounding.
    After i put no T-stats in, I was able to run the boat over an hour without an alarm where before, I ran .2 and about .5 hours before the alarm kicked in. So if i was at 180 degrees indicated, within .2 and .5, is it possible that i reached max indicated temp on GPS by running for an hour at 5000 rpms - and alarm didnt sound because the sensor was ok - and not overheating. (does that make sense?>)_

    As far as the t-stats in the block - the T-stat with the 3 marks on top is in the forward T-stat slot and the 2 mark T-stat is in the rear - toward the stern of the boat.......I am pretty sure that's how the old one came out.

    Plan of attack -
    1. try to find the relief valve - clean it out
    2. Remove T-stats, mix some vinegar and water and pour down into T-stats and then seal off as best as possible and try to back flush
    3. Remove Intake Covers and clean if needed
    4. Remove and replace impeller and gasket - see if that helps

    If none of the above work - i guess i will be buying a trailer and shlepping it down to the dealer.

    Thanks for the assistance guys - any other ideas will be greatly appreciated.

  5. #5
    Join Date
    Sep 2008
    Location
    Hague, Virginia, USA
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    Default Re: Honda BF150 overheat alarm

    Sounds like a good plan. Keep us posted.
    CHawk 25 DLX

  6. #6
    Join Date
    Mar 2013
    Location
    Merritt Island FL
    Posts
    49

    Default Re: Honda BF150 overheat alarm

    UPDATE:

    Ok,.......I got some time - here is what i did and the results.........I pulled the T-Stats out - i then poured some vinegar down into the T-stats, let it sit for a bit, flushed it with garden hose - (i had the lower unit off when doing this) - some minor pieces came out - nothing super large - but enough to tell me there was a little crud built up. I continued the process till nothing came through.......

    I then replaced the impeller and gaskets - i noted a little bit of cracking around the fins/blades of the impeller - it wasnt broken, no broken pieces....the tabs were actually worn off tho......so replaced with impeller kit.

    I could not locate the Check-valve Hondadude discussed - i think it was in the lower rear of the unit - and that would require me to drop the mid section - if it's what i was looking at....

    I took boat out that day - (evening) ran in some rough seas.....1-1.5, 2ft river waves.....for about 30 minutes, then i ran in an idle zone for 2 hours....temp was never above about 175-180 on the GPS alarm - no overheat horn. (Thinking smuggling, i may have fixed it)

    Take boat out yesterday -ran about 20 minutes to an island ...temp 175-180 on nmea2000 GPS Connection....no overheat.

    Leave the island, waves are pretty big, run about 20 minutes in tall waves, temp at 175-180 ish......slowed down to get into canal, tilted motor up for shallow water...speed at idle, waves pushing into splash well compartment in the rear from wind driven waves....motor tilted up.....i watch the temp go up to 200 and stay there till i got into shore.......

    PUZZLED.....dont have clue unless due to being tilted up and rough seas - not enough water getting into the intakes......

    stumped me

  7. #7
    Join Date
    Sep 2008
    Location
    Hague, Virginia, USA
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    Default Re: Honda BF150 overheat alarm

    First, if you have not done so, pull those intakes and check for clogs and restrictions.

    Pull codes by shunting your service connector as described on this forum many times. (If you need the procedure, send an e-mail to me at [email protected].) If you do not get a code "24" (overheat sensor 1) or "25" (overheat sensor 2) then I suspect your engine is doing just fine but there is something screwed up with the NMEA Interface or your Garmin 441. If you are still concerned about the engine, run it with the cover off and check with a heat gun. As mike said, if all is normal, you should be seeing about 158 degrees +/1 at the exhaust manifolds.

    Go on line to Garmin and ask if they have had any issues with the Honda NMEA outputs to the Garmin 441. They have a very good customer service and technical support department.
    CHawk 25 DLX

  8. #8
    Join Date
    Mar 2013
    Location
    Merritt Island FL
    Posts
    49

    Default Re: Honda BF150 overheat alarm

    Thank you again for the guidance and direction - i am going to try to get off work early today and i'll try to see the codes and clean the screens.....i'll let you know....

  9. #9
    Join Date
    Mar 2013
    Location
    Merritt Island FL
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    Default Re: Honda BF150 overheat alarm

    Ok - today when I got home - I followed the advice of Chaulk - here is what I did

    Cleaned the screen -nothing there
    I did the shunt on the connection to see all the codes-worked just as you said it would. The code I got was one long, 4 short -
    I looked that up- It said Aic valve - I believe - I then reset the code and went for a boat ride it stayed right at 175 on the Garmin Temp set with the nmea 2000. No iternal alarm -

    I then rode up to speed at 5000 rpm, 35 mph - and watched Garmin climb to 225 on Temp.

    I did not get any alarm - no overheat or anything.......

    I checked for any codes - there were none

    I guess ill be calling garmin on Monday

    any other thoughts??

    thanks all!

  10. #10
    Join Date
    Mar 2009
    Location
    Cincinnati, OH USA
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    4,176

    Default Re: Honda BF150 overheat alarm

    The relief valve is at the base of the exhaust manifold on the starboard side of the motor. You may have to pull back the side panel to get to it.

    When you talk to Garmin, check to see if they know what temperature to expect to see. As I said before, it will be higher than the thermostat temperature, but I do not know how much higher.


    Mike

  11. #11
    Join Date
    Sep 2008
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    Hague, Virginia, USA
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    Default Re: Honda BF150 overheat alarm

    Yes, do check the relief valve. Your statement "I then rode up to speed at 5000 rpm, 35 mph - and watched Garmin climb to 225 on Temp." would be an indicator that the relief valve is not working. But the fact that no alarms are sounding points to the liklihood of another problem.

    Mike, on my 225 the t-stats are fully open at 158 F. My external heat sensors on the manifolds read 160 F at trolling speed. At plane speed, the port manifold stays at 160 F, but the starboard manifold drops to 145 F, which is a strange situation that I have posted on this forum before, and no one has provided a good explanation. Likely do to internal water flow, but I have not been able to figure it out. The point being that at least on my 225 the T-stat wide open temp closely matches the manifold temperature.

    Jeff - I also recommend that you run the motor as before and use a heat gun to confirm the temperature of the manifolds. If they are in spec (which I think should be around 160 F to 170 F, but not sure of that), then I don't think you have an engine problem at all, but rather a problem with the interface between the Honda NMEA 2000 output and the Garmin reading.

    Here are some possibilities:

    * The Honda NMEA 2000 temperature output is correct, and you are indeed overheating. That's why you need to use a heat gun on the manifolds to check. But the fact that no alarms are going off and no codes are being thrown, is a pretty good indicator that your engine is running fine. Use a heat gun to confirm.

    * The Honda NMEA 2000 sentence for temperature output is incorrect (not likely, but possible - would require an ECM update to fix.)

    * The Garmin 441 is misinterpreting the NMEA 2000 temperature sentence from the Honda ECM. Requires a software update from Garmin, which is normally pretty easy to do. On my networked 4208 and 3205 its a simple download and transfer to a memory chip.

    * The Garmin 441 is mis-calibrated for the temperature reading. Re-calibration is usually not too difficult on most of the larger Garmin's. Don't know about yours..
    CHawk 25 DLX

  12. #12
    Join Date
    Mar 2013
    Location
    Merritt Island FL
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    49

    Default Re: Honda BF150 overheat alarm

    I'll be taking it apart today and checking the valve - see what it looks like i will do the IR gun and try to call Garmin

    I'll let ya'll know

  13. #13
    Join Date
    Mar 2013
    Location
    Merritt Island FL
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    49

    Default Re: Honda BF150 overheat alarm

    just got off the phone with Garmin product support - Kevin - he wasn't a lot of help - when I asked where the nmea2000 gets info - he said from the motor, he didn't know where or what sensor - he advised it would be through the nmea2000 gateway - on the Honda - he said it only gives whatever information it gets from the motor - he had no idea how it got the temp.

    I'll try to get the check valve done today

    jeff

  14. #14
    Join Date
    Mar 2013
    Location
    Merritt Island FL
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    49

    Default Re: Honda BF150 overheat alarm

    Ok - took boat to mechanic - he advised it was the poppet valve - i presume he meant the relief valve you'll were talking about - it was time for the 100 hr service - i went ahead and had him do the service (fluids, grease, etc) and i told him about the overheat condition - he pulled it and said it looked corroded and stuck.........
    took boat home - havent run it since......we'll see.....
    he said he tested in tank for 30 minutes at idle, no overheat....so lets hope...
    any other ideas - is the poppet valve the same as the relief valve??

    thanks

  15. #15
    Join Date
    Mar 2009
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    Cincinnati, OH USA
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    Default Re: Honda BF150 overheat alarm

    Yes.

    Mike

  16. #16

    Default Re: Honda BF150 overheat alarm

    What was the result? I'm seeing the same issues with a Lawrance LMF-400 multifunction gauge on a nema2000 system on a 2014 BF150. My cruising temps are about 190-195 with a max about 225. No alarms. I thought it was a compatibility issue with the data being supplied from the engine interface. I'm interested to see if you resulted in lower temps being reported.

  17. #17
    Join Date
    Mar 2013
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    Merritt Island FL
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    Default Re: Honda BF150 overheat alarm

    I really don't have an answer why it's occurring. I installed the same nmea2000 set up with the same Garmin 441s gps on my son in laws new pontoon with a 90 Honda. It's a 2014 model

    the new ones have the nmea cable and connection built in to them. All I did was plug a backbone into the cable and then that cable into the gps. His is spot on with temp and all engine controls with no additional hardware or connections. His temp was 156 all day long
    my engine displays 180 all day long on gps but no over heat.

    I I am a true techtard. I have no idea why. My mechanic is a honda cert and and he can't figure it out. The warnings and alarms are working properly and there is no excessive heat from engine
    I am stumped but it's working without issue

  18. #18

    Default Re: Honda BF150 overheat alarm

    Thanks for the info. It peaked my interest because I just put the system in and it was reading higher than the t-stat ratings. I just figured it was a compatibility issue. So, just to clarify, the was no change when you replaced the bypass valve?

  19. #19
    Join Date
    Mar 2013
    Location
    Merritt Island FL
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    49

    Default Re: Honda BF150 overheat alarm

    I no-longer get an overheat alarm after i cleaned out the jackets, replaced the check valve, thermostat and the impeller. According to my gps, my engine is running at about 175-190 somewhere in that range - but i am no longer gettting the alarms.

    If you ask Hondadude or Chawk - they are experienced in these items and can probably better assist you.

  20. #20

    Default Re: Honda BF150 overheat alarm

    Guys I'm having same issue. My situation differs as my Lower Unit is a JET. Got in heavy grass last night and heat warning set off. I have checked Valve 15, impeller,and all water lines. Engine is peeing fine. Here's the first priority for me. I removed lower unit to inspect impeller and notices a rubber washer laying on ground. Same diameter as the top of the impeller cap. Someone please tell me where it goes.

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