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BF135 Overheating Alarm and Control Panel Question

jnorton70

New member
HelloAll. I am new to outboards and could usea little help. Apologies in advance fora long post.

Ihave twin outboard BF135s that have about 1700 digits in the serial number separatingthe two that happens to fall between a control panel part change. The engine in question (SN BARJ13011946) currentlyhas the incorrect control panel (part# 32340-ZW5-506(2LED)) versus the control panel it should have (part# 06323-ZZ5-764 (4LED)). The previous owner battled an overheatingissue while he owned it as well. He put4 new temp sensor, new thermostats, and a new water pump. I can’t remember if he changed the reliefvalve or not but from my inspection of it appeared to be relatively new. He also did a flush of the system with achemical designed to clean cooling systems.


Questions: 1. Does having the incorrect control panelmatter? Ie. Can this causefalse high temp alarms? It appears toonly be lights that receive their signal from the ECU, however, I cannotconfirm this from the service manual. 2. Does the control panel send a signal back tothe ECU that would cause this high temp alarm and for the engine to go intolimp mode?

3. The control panel appears to be optionalequipment; can I disconnect the control panel lamp assembly to sea trial the boatin order to verify this is the fault creating these symptoms?

Thisis the symptoms and troubleshooting I have done so far.
Theengine runs fine and does not have an overtemp alarm at below 75% or so throttle. Above 75% throttle the engine will run finefor a couple of minutes and then the overtemp alarm will sound, the engine willretard to 1800 RPMs until it “cools down” and then it will run fine again. I have checked the temperature of the head,block, exhaust manifold, and water discharge from the thermostat which allseemed to be within reasonable parameters to me (Block 150, head 140, exhaustmanifold hottest point 168, and the cooling water discharge after thethermostats was 120). I have tested all4 ECT sensors and they all have the same resistance measurements +-5% (2K ohmsat room temp to around 500 ohms at 170 degrees) from 70 degrees to 170 degrees. The thermostats were tested and opened morethan 3mm at the appropriate temperatures. The pressure valve was not stuck open or closed; it seemed to operatefreely. The seat was in good shape andthe there was little corrosion. The waterinlet vents had no apparent foreign matter or marine life clogging them. The water pump is pumping adequate water at areasonable pressure (I didn’t hook up a pressure gauge but would guess 2-6 PSIfrom idle to 1200 RPMs, a good stream coming out). I cleaned the thermostats and pressure reliefvalve, reinstalled and took the boat out on a sea trial with the temp gun. There was no change; the overtemp alarmsounded within similar timeframes as before above 75% throttle.

Isthere anything I missed as far as troubleshooting goes that anyone canrecommend? I would like to verifyoperation of the control panel before buying another one I may not need. Another step I have considered is testing thewires to see if there is a problem there, however, with the consistency of recreatingthe when the alarm sounds I tend to lean away from a wiring problem that onlymanifests when at high speeds. Whentrolling open ocean the ride is rougher than when I was testing in the lagoonthat was flat water. It is not out ofthe realm of possibility though. Thetime that can be wasted looking for an intermittent fault in a wire is a deterrenttoo.

Thanksin advance for any recommendations.

 
Sounds to me like a real overheat you have there and unrelated to the panel. I don't have a 130 but there is another post out there concerning 175's I think where an overheat was traced to a grommet of a water tube fitted on the oil pan. Grommet for the other engine is 19252-ZY3-000 just so that you can trace in in the parta catalog. P/N may nor apply to your engine but you could have a similar situation with another part number grommet or nothing at all related to this, just an idea.
 
As mentioned above, start with grommets at waterpump and tube into the mid section.You mentioned water pressure at 6psi, if this is at mid rpm it's way too low, should be at least 20psi.
 
As mentioned above, start with grommets at waterpump and tube into the mid section.You mentioned water pressure at 6psi, if this is at mid rpm it's way too low, should be at least 20psi.

Thank you for the help. I think you are pointing me in the right direction with the grommet. When I was running the boat in a tank the other day I noticed there was water coming from a couple opening in the lower unit that I was not expecting. I thought it was odd, but didn't pay it too much attention since I didn't the system flow.

Anyhow, I am going to pull it apart in a day or two and see what is going on.
 
Do not take it for granted that your psi water pressure is correct like you said 2-6 psi at 1200 rpm at idle check it with a gauge .Do a static water pressure check remove the gear box make an adapter to fit a water hose onto the inlet tube . Take the thermostat out on the one side where the water goes out once the thermostat has opened plug it with some Blue Tack make a cover in place of the original thermostat cover and fit a small pressure gauge onto it . plug the pee hole and the vst return water line . Turn on the hose make sure the hose water pressure is good .Too much pressure will open the pressure valve the gauge will drop at a certain water pressure the guage must stay constant if there are no leaks.
 
I am going to try and scrounge up a pressure gauge and do the static water pressure test Tegweni suggested.

Last night I ran both engines in a tank at the same time. There is no doubt now that the other engine has mush higher water pressure. I checked the grommets as suggested. I put the garden hose on the water tube and there were no leaks coming out. I replaced the one on the water pump since I had the part on hand.

Since I had access to the water pump and had a rebuild kit I opened it up. Everything looked good. I replaced the impeller since I have a few spares.

Put it it back together and ran it with no appreciable change in water pressure. The engine giving me trouble has a lot more water coming out of the speedometer tube hole than the other one does.
 
The grommet that has affected other engines is at the oil pan, the mid section has to be removed. Will try to find the OP.

I can see that grommet through my mid section. I put the garden hose on it and watched for leaks. There were none. I took the mid section off anyways and visually inspected the grommet. It wasn’t in good shape. I have one order. It will be here in a couple weeks.

But since it wasn't leaking is there any reason to believe that was causing the problem. Is there anything in the oil pan to check?

Thanks.
 
I don´t think so. Could the grommet be restricting flow more than leaking?


The grommet was slightly turned in on the end of the oil pan side. Maybe it is worse when the tube setting plate is tightened down on it.

This engine has had a lot more water coming out from the cavity where the water pump is housed then my other engine (ie a fountain out of the shift rod speed sensor holes on the front top of the gear case assembly). I thought it could be this grommet leaking but that would go down the same channel as the hot discharge cooling water. Which leaves me with excessive back pressure from somewhere before the pee hole restricting flow to the engine and increasing the volume of water being sent out the pump housing hole and up the shaft????

here is the link for a video on YouTube. My phone doesn’t want to post pictures or videos here. https://youtu.be/FrqlMzSlW4Q
 
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I don´t have any more ideas. Internal engine passageway blockage? Are the engines operated in salt water and if so, are they flushed after use. Maybe someone else can chip in. Definitely too much water coming out of that cavity.
 
I don´t have any more ideas. Internal engine passageway blockage? Are the engines operated in salt water and if so, are they flushed after use. Maybe someone else can chip in. Definitely too much water coming out of that cavity.

Yes all saltwater here. But I flush after every use with Salt Away and the previous owner is the one who showed me Salt Away. He also did an in depth flush with a commercial product designed for flushing cooling system of marine engines when he was having trouble.

If an internal passageway of the engine block, head, manifold was blocked I would expect much better flow/pressure out of the pee hole since, to my understanding of the diagram, the pee hole is before the block, head, manifold in the flow. But I could be wrong; the diagram isn’t great. When I had the hose connected to the water pump discharge tube there was good flow out of it. So I don’t suspect a clog in the peephole.

Thanks for the ideas. I really appreciate being able to bounce ideas back and forth.
 
In case anyone else has a similar problem. Edited first post to delete irrelevant items.

The culprit was a misaligned water pump housing Leaking water to the cavity that houses the water pump, which explains the water that was coming out of the speedometer tube hole.
 
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