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BF 225 Issue

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RobHales46

New member
Good day all.

New to the forum, thank you for accepting me.

I have an issue with a 225 Honda. 400 odd hours, runs fine at idle but as soon as you start loading it it develops an oil alarm. The oil pressure stays at 170KPA which was slightly below spec
Stripped the engine, mains and big ends looked a bit worn. Removed crank and measured up. Within spec. Light polish and new bearings throughout, big ends and Mains. New thrust washers. Oil clearances all within spec. End float within spec. Oil pump stripped and measured. Within spec. New High pressure sensor and low pressure sensor fitted. Assembled and tested. Mechanical oil gauge shows consistently above 200 KPA at idle. Goes up to 500 KPA at rev. Hold revs for a minute or two and the green light goes out and alarm sounds and engine will not rev over about 2000 RPM. Switch off immediately and restart, all ok. Rev for a minute or two. Same issue. Oil pressure remains above 200 KPA at idle even when alarm is sounding
Have swapped out the ECM.

Had it on the Dr H diagnostic tool. No fault codes.
when looking at the data list while running nothing appears out of the ordinary

any ideas????

Regards
Rob
 
WOW - that's a head scratcher.

What year or what are the first four digits in the engine serial number?

Are you using an OEM oil filter? If not, do so. Or use a NAPA Gold 1356.

Did you actually replace the LP and HP oil pressure sensors?

Closely inspect the six-pin connector from the oil sensors, heat sensor, and knock sensor that are located in the V of the block. Look for any corrosion, recessed pins, shorts, or other wiring issues. Especially check ground wire.

Have you checked for overheating, which could thin the oil?

What weight oil are you using? I've been using Merc 25W-40 FC-W since my engine went over 1000 hours.
 
Hi Rob,
Welcome to the forum. Sorry you're having troubles.

I'm far from being an expert on the 225 but you wanted ideas so I thought I'd kick this around with you...

Since you say you swapped out the ECM and the same, exact problem persists, it's pretty easy to eliminate that as the cause. Although....you never know. But two ECMs with the exact same problem??? Highly unlikely.

You say that you've verified oil pressure with a mechanical gauge and replaced both high and low oil pressure sensors.
But I'm not clear about what low oil pressure is being reported NOW at idle.
Initially you saw 170 kpa and did all the work. Was that read using Dr.H? You say the mechanical gauge reads 200 kpa NOW, at idle, while the issue is happening but what is the pressure in data? STILL 170?

And...if I misunderstood and Dr.H is now reporting 200, then I have to think that you may have a wiring or connection problem between the OP sensors and ECM.

The ECM operates the oil lamp and is turning it on and then off during the "event" and apparently de-rating the power...SO....

The ECM is seeing something it doesn't like.
But that should still flag a code, right?
Very odd.

Might sound strange but I would start by cleaning the battery and starter connections along with all the grounds I could get to.

I am always suspicious of the effects vibrations have on wire connections so going back and looking at the terminals for the op sensors in the ECM connector might be a good idea.

Another possibility is that one of the sensor wires has been compromised in some way. Again, vibrations and chafing go hand in hand.

If at all possible, I suggest isolating the sensor wires and load testing them using a head lamp. Wiggle and move them while watching the light.

Before I did all that though, I would check the charging voltage for AC ripple at the same rpm that you notice this being triggered. It's simple and easy to do and alternator ripple has been known to cause strange problems like this one.

Electrical interference....known as EMI or RFI... can also cause an ECM to act up. Ignition coils can contribute to EMI when they start failing and could cause "phantom" symptoms like this. Radar and some high gain radio equipment might also be suspects.

I hope you get it figured out without too much pain.
 
Hi guys.

I am away from the engine for a couple of days, but will update you once I get back to it. Many thanks for your inputs.

many thanks
Rob
 
Hi,

quick update. I got a new sub assembly and assembled the engine. No more alarm.
Hope to put it in the water in the next week or two and give it a through test.

will strip the old engine again when time permits and have another look.
 
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