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Honda BF60a overheating issues

H

hurricane oz

New member
Hi all. I have a 2019 BF60a LRT that is driving me nuts overheating. It runs fine at idle or very low speed (under 2500 rpm) but when you get on top, after 100-200yds the overheat alarm goes off and drops the rpms. It shoots out a great stream of water.
I have replaced the thermostat, water temp sensor, entire impeller kit, checked the intake screens and run de-limer through the cooling system twice. None of that improved the problem. At first it would run fine up to 5000 rpm before overheating- over two weeks time that has steadily dropped to 3000 rpm before overheating.
Something that seems odd to me is after the overheat alarm goes off and I turn the motor off, I can start it up again immediately with no alarm going off. Doesn't seem like it would cool that fast.
At this point I don't know what direction to look. Thanks for any advice/info
 
Progress report.
Checked motor with IR heat gun to confirm it was in fact overheating. Ran it with the thermostat out up to 5500rpm with no alarm. So we've deduced it's indeed a water flow problem. Took the housing cover off, poked and prodded into the holes with wire to break up some of the deposits/corrosion in the water channels around the block, blew air thru them, wire brushed, etc. Alternated running vinegar and DLR thru with water hose attached. Have gradually improved to about 4500rpm with thermostat in before it throws alarm. Still getting some slime on thermostat each time we check it. Plan to continue flushing with vinegar and DLR.
I'll report how it goes
 
Yeah, that salt is a mineral pretty much every outboard will "absorb". Although, I worked for years on lake bound boats and it's surprising how much minerals in fresh water will "plate out" on the hot sections of an engine.

I was trained in my engine cooling systems repair class that 1/64" (0.016") of deposit in a cooling passage will add resistance to the transfer of heat the equivalent of about 2" of steel. Pretty amazing!
It doesn't take much to really ruin your month.

Glad you caught it in time to get it cleaned up. Please keep us updated on your progress. I'm sure there are plenty of owners here that can use the valuable information you can provide.
 
jgmo said:
Yeah, that salt is a mineral pretty much every outboard will "absorb". Although, I worked for years on lake bound boats and it's surprising how much minerals in fresh water will "plate out" on the hot sections of an engine.

I was trained in my engine cooling systems repair class that 1/64" (0.016") of deposit in a cooling passage will add resistance to the transfer of heat the equivalent of about 2" of steel. Pretty amazing!
It doesn't take much to really ruin your month.

Glad you caught it in time to get it cleaned up. Please keep us updated on your progress. I'm sure there are plenty of owners here that can use the valuable information you can provide.
Click to expand...
It really doesn't take much. Those cooling channels around the block are small on a Honda and, of course, the thermostat opening is very small. I wouldn't have guessed the little bit of salt and deposits I could see would cause a problem, until you start poking around with a wire into those unseen areas. Even then it wasn't a huge amount.
 
NSDON said:
Are you flushing with the outboard running in a barrel when using the cleaners?
Click to expand...
No, I'm just pouring them into a water hose and hooking the hose to the hose flush attachment on the motor. Turn on the water just long enough to push solution into motor, then turn water off and let it soak in there for 15 mins. Then turn water back on and flush for 15 mins. I alternated between vinegar and DLR.
Had I known from the start it was a water flow problem I would have used a barrel and just run cleaner thru it constantly. Wasn't set on water flow issue since it was pissing fine. By the time I figured out it was for sure a water flow issue I almost had it solved using the hose method so I stayed with what was working.
 
Yesterday I had run 2 rounds of vinegar and was flushing my 2nd round of DLR when she sort of coughed and spit out a BUNCH of crud. Water flow out of the hub and pisser immediately jumped. Haven't had a chance to drop her overboard yet today but I feel like we got her.
It took 5 soak/flush rounds with white vinegar (2 total gallons) and 4 with DLR (1.5 total gallons) to get the big gunk blowout I was looking for.
Hopefully that's that but I'll report back when I've had a chance to run it.
 
From what I read here, a barrel is by far the best way to flush a Honda.

Hopefully you got the problem cured, let us know how it turns out.
 
NSDON said:
From what I read here, a barrel is by far the best way to flush a Honda.

Hopefully you got the problem cured, let us know how it turns out.
Click to expand...
May have to go that route. Ran it today with mixed results- on one hand I was up to 5000rpm for several miles several times with no alarm.
On the other hand I had alarm go off 3-4 times within a couple miles twice. Pulled thermostat and still getting some crusty stuff in it.
Thinking I've busted loose a bunch of stuff and it's still breaking up and working it's way through but at this point I'm just guessing.
Gonna run some more DLR through it tomorrow- if that doesn't get it Ill have to try the barrel.
 
Seems like we're going backwards now. Alarm goes off within 100yds of getting on top. Will run all day at 2200rpm with cool water flowing from pisser. Get on top, alarm goes off within 100yds and very hot water out of pisser all morning.
Extremely frustrating.
I'm just about to the point of taking the thermostat out and running it until it seizes up or blows up, then droppin the piece o crap overboard.
 
Took out thermostat expecting it to be gunked up- clean as a whistle. Ran it a mile with thermostat out, no problem. Put thermostat in ran a couple miles, no alarm. Ran another 3 miles, no alarm. Yesterday ran 3 miles no alarm.
Maybe a good cussin did it some good.
 
I've run the boat 4-5 more times, 3 to 7 miles per trip, without throwing an overheat alarm. Seems like the issue may be fixed (fingers crossed).
Thank you all for pointing me in the right direction, I really appreciate it. This board is a goldmine for Honda owners.
 
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