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Honda BF150 and Honda Civic

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PaulBF150

Contributing Member
I heard there might be some similarity between these motors. Anyone can confirm? If so, provide more details so I can accomplish the following:

Thought was to acquire the Civic engine from junk yard and replace my Overheating BF150 Engine short block.
 
The car engine is different. Have you removed and checked water flow from the exhaust? You must have a blockage somewhere, these motors do not have problematic cooling systems
 
iang6766

Yes have pulled off the head and exhaust manifold, cleaned all and back together. Done this now 3 times. Each year basically the same overheating issue. See my posts on BF150 Overheating and the continued version also.

From what I gathered in recent post, my issue may be associated with heat transfer. The cylinder jugs corroded with Aluminum Oxide. Although being cleaned with various flush fluids and when engine open did wire brush around the jugs. Same results.

Trying to determine if passing higher volumes of water through the engine is helpful or counterproductive. Suely Honda has designed several mechanisms, Pressure regulator, small openings in head gasket and thermostats that only open slightly.
 
I have yet to come across any honda with unsolvable overheat issues. May I ask what version of DrH you are using? Your post on temp monitoring indicates block temp is not shown, the factory version which I have definitely monotors block temp. You are missing something somewhere in that cooling system or and this is very possible, you may have a faulty ecm triggering an overheat prematurely. Your block temp can go as hogh as 110deg before triggering an overheat.
 
The version of DrH is not listed, likely a boot leg version since instructions say not to update code. Plus, interface box was missing a diode that prevented operation but works now obviously. It could be what engines it supports for marine motors date rang 2004-2006. My engines are 2010.

Well, It does report many parameters and I can graph them and playback too.

The Block thermostats are set for 140F (60C) so having a 20degree margin seems small, since my simulated sensor triggers alarm at 160F according to Dr H. Any idea what the max temp is? As for the ECM I could insert some resistance in series to allow for a little more wiggle room. Heated sensor resistance comes in to about 400 ohms that triggers the alarm. Could insert say 10 or 20 ohms.

As for cooling system I think I addressed everything, that is why I'm engineering alterative, maybe crazy but this engine drove me crazy already.
 
iang6766 said:
I have yet to come across any honda with unsolvable overheat issues. May I ask what version of DrH you are using? Your post on temp monitoring indicates block temp is not shown, the factory version which I have definitely monotors block temp. You are missing something somewhere in that cooling system or and this is very possible, you may have a faulty ecm triggering an overheat prematurely. Your block temp can go as hogh as 110deg before triggering an overheat.
Click to expand...
Ian, thank you for your shot of optimism here. As you can see we are going to more and more Desperate Measures to solve this temperature problem. Paulbf150 and myself seem to have the same problem and others may have it too. I don't expect this is the first time it's ever been encountered so maybe somewhere in your past you encountered this set of symptoms. Can you think of any other temperature problem Solutions that you found have not been mentioned here yet?
 
I have never had an overheat issue with any of the 4 cylinder motors that has been unsolvable.It's hard to comment with physically inspection the cooling system . In my humble opinion, the waterpump is more than adequate for this motor in terms of volume of water. You guys must be missing something. Starting with the pump, corrosion under the base plate is fairly conmon and an cause airation in the cooling system at higher speeds. Oil pan corrosion where the water tube grommet fits, can leak reducing water pressure. Silt build up around cyl 4. Blockage in passage leading from block to thermostat.Blocked outlet from thermostats in lower exhaust manifold mixer. Relief valve not opening properly.
Mechanically, combustion gasses entering water passages through corroded pit holes or leaking head gasket.Apart from that, I'm at a loss.
 
Thank you Ian, this will help me direct my next efforts. As to your comment

Starting with the pump, corrosion under the base plate is fairly common and can cause airation in the cooling system at higher speeds. Oil pan corrosion where the water tube grommet fits, can leak reducing water pressure.

I presume that the base plate corrosion should be evident immediately under the impeller assembly.. I can take the lower unit out and and disassemble the impeller parts. This had previously been done about six months ago. Just to be sure .. when looking down the drive shaft towards the prop does the drive shaft rotate clockwise? Just checking to ensure I didn't install the impeller backwards.
Would the corrosion in that area be in the passages leading to the impeller?

Next, I would expect to disassemble the water tube that goes up into the engine by removing the 10 mm bolt and Metal flange that hold the top grommet to the base above. Replacing this grommet was noted by another poster as solving their temperature problem. If I do this disassembly will potential corrosion be obvious right there looking up through the hole into the lower engine?

Any insights or comments would be appreciated
 
As to your comment:

Blocked outlet from thermostats in lower exhaust manifold mixer.

I'm assuming this would involve removing the large diameter black rubber hose that comes from the dual thermostat housing and connects to the lower exhaust housing
And looking for corrosion blockage at the lower connection point.
 
Best way to deal with corrosion in oil pump water inlet if present, is to remove midsection so that a bunny tail wire brush can be used to clean it . If badly corroded you can use sikaflex round the grommet to get another couple of years or replace the oil pan. Water passage under tgermostat is referring to the small passages through the chain case, I have seen that blocked.
 
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