Logo
FULL SITE MENU

Over heating bf 150

W

wajira

Regular Contributor
this is two years old engine run only 600 Hrs, it was start to giving over heating alarm, so i checked thermostat, both the thermostats are badly damage so i replaced with new, still the problem is same,good water pressure from the pilot hall but still i opened water pump and replaced new impeller, no changes, same alarm, alarm is starting after 4500 rmp, and i touched and see at the top of exhaust manifold it is too hot, so i opened cover of anode in the manifold to see how is the inside, it is too clear no blocked or calcium scales inside the water passage. and finally i opened all the water outlet hoses and i opened all the parts from down side not found anything abnormal. thermo sensor on the exhaust manifold also working fine. still couldn't find the prob, OVER HEATING after 4500 rmp anybody got idea what can be

wajira
 
This topic is of interest to me as I also have the same problem on one of my twin 2004 BF150’s. Like you I have done all of the maintenance stuff, replace impeller, thermostats, etc... I still have the same problem of starboard engine setting off alarm and reducing power or shutting completely off if ran above 4000 rpm. This is more of a nuisance to me rather than a problem as I seldom, if ever, run above 4000 rpm due to most of my boating being offshore. I just spent the last 3 days running 12 to 15 miles offshore, never above 4000 rpm, with no issues at all. I’m beginning to believe I have a bad temperature sensor so I’m currently in the process of swapping sensors between motors to see if I can duplicate the problem on the port engine. With all that said, you stated “thermo sensor on the exhaust manifold also working fine”. You didn’t mention the year model of your motor but if it’s like my 2004 you do realize you have two more sensors on the thermostat housing that to my understanding could possibly be setting the alarm off? For my 2004 all of the sensors are the same, I assume the same is for your engine. You may want to purchase a new sensor and start swapping sensors until you hopefully eliminate the problem. Anyway, just a thought. Maybe a professional will chime in that can make more sense of this.
 
N2Gulf said:
This topic is of interest to me as I also have the same problem on one of my twin 2004 BF150’s. Like you I have done all of the maintenance stuff, replace impeller, thermostats, etc... I still have the same problem of starboard engine setting off alarm and reducing power or shutting completely off if ran above 4000 rpm. This is more of a nuisance to me rather than a problem as I seldom, if ever, run above 4000 rpm due to most of my boating being offshore. I just spent the last 3 days running 12 to 15 miles offshore, never above 4000 rpm, with no issues at all. I’m beginning to believe I have a bad temperature sensor so I’m currently in the process of swapping sensors between motors to see if I can duplicate the problem on the port engine. With all that said, you stated “thermo sensor on the exhaust manifold also working fine”. You didn’t mention the year model of your motor but if it’s like my 2004 you do realize you have two more sensors on the thermostat housing that to my understanding could possibly be setting the alarm off? For my 2004 all of the sensors are the same, I assume the same is for your engine. You may want to purchase a new sensor and start swapping sensors until you hopefully eliminate the problem. Anyway, just a thought. Maybe a professional will chime in that can make more sense of this.
Click to expand...

Try Item 15 http://www.boats.net/parts/search/Honda/Outboard Engine/2004/BF150A4 LA/MOUNT CASE/parts.html
It might be seized up.. water pressure relief valve
 
my boat with single BF150 2010 model, i have test the engine with Honda diagnostic tool(Dr.H) this engine got 4 thermo sensors one in the block,two on the top side of thermostat housing and one on the exhaust manifold.while running the engine all the sensors are giving correct reading (50 c' to 65 c' ) but only exhaust manifold sensor reach 70 C'. once its cross the 70, over heat alarm starting and engine rpm reducing. this is what i got information from Honda technician,they already report to Honda japan but seems to be not yet got answer,
If the water pressure relief valve stuck how it will be over heating ?,i saw the valve it is fully closed and i move it with the screw driver. if its stuck opened it can be over heating,

wajira
 
my boat with single BF150 2010 model, i have test the engine with Honda diagnostic tool(Dr.H) this engine got 4 thermo sensors one in the block,two on the top side of thermostat housing and one on the exhaust manifold.while running the engine all the sensors are giving correct reading (50 c' to 65 c' ) but only exhaust manifold sensor reach 70 C'. once its cross the 70, over heat alarm starting and engine rpm reducing. this is what i got information from Honda technician,they already report to Honda japan but seems to be not yet got answer,
If the water pressure relief valve stuck how it will be over heating ?,i saw the valve it is fully closed and i move it with the screw driver. if its stuck opened it can be over heating, ( the 15 number part is thermostat that i already replaced. )

wajira
 
Back
Top