Logo
FULL SITE MENU

Starboard BF200 High Fuel Consumption

B

Blacktimes

Regular Contributor
Hi Guys, took the boat out this weekend and starboard BF200AK2 is consuming about 6 litres/hour more than the port engine. Last time I took the boat out last week both engines had a perfect match. Temperatures are the same. Ran the Dr. H and no faults, no fault codes. Engines have about 130 hrs on them. No smoke or anything, starboard runs perfect but with higher consumption. I don´t think it is anything major or that a compression check needs to be done, my feeling is maybe something stuck, could it be the IAB? Also played around a bit and perfect match until 2100RPM, that´s when the split starts, under that both are a perfect match. I normally run the engines at 3400-3600RPM and only troll entering and leaving the marina. Any ideas? Thanks!
 
The IAB doesn't kick in until 3950 rpm. But check it anyway to make sure it is not stuck. Also, check the vacuum hose coming from the IAB solenoid to the IAB diaphragm.

See attached.

View attachment Honda 225 Intake Air Bypass.pdf

Next, check your fuel pressure at the fuel pressure relief bolt on top of the cover to the HP fuel filter. It should be between 42 and 49 psi at idle on warm engine. You will need a 6 mm adapter. While you are there also pull the HP fuel filter and check that. That is often the source of fuel performance issues. If it's black or collapsed, replace it.

If fuel pressure is too high, the first thing is to clean and test the fuel pressure regulator.
 
Hi Chawk, checked the fuel pressure off the HP Filter Housing 6mm plug and is ok. Checked HP Fuel Filter, green, not black or collapsed, ok, replaced it anyway. Checked the LP Fuel Filter, yellow, not black, ok, replaced it anyway. Checked IAB, moves freely, vacuum hose at diaphragm, ok. Checked air intake wire mesh filter, ok. Pulled all the spark pugs, all clean and in the same good condition. Pulled the O2 Sensor and found what seems to be some salt build ups on the sensor and one of the four holes plugged. Engine is 2011 S/N BAEJ-1700111 so O2 Sensor Service Bulletin is not applicable. Drained the VST, no water. Once again no faults or fault codes.

Could the plugged O2 Sensor cause the fuel consumption increase?

Thanks
 
Last edited:
Yes, a failed HO2 sensor will increase fuel consumption. They need to heat to ~600 F via the internal heating element to work properly. A properly working HO2 sensor varies the fuel injectors' pulse for optimal running.

Service Bulletin #71 (published in October 2010) covers a situation where the ECM does not detect a failed HO2 sensor. However, supposedly that SB only is for a small number of SN's below yours, i.e. BAEJ-1600001 ~ 1600101 and BAFJ-1600001 ~ 1600012. The fix is to replace BOTH the ECU and the HO2 sensor. The replacement kit is 06347-ZY2-317. It's $899 on Boats.net. That's ******** a bunch of money if you're not sure it is, indeed, the HO2 sensor.

There is a procedure in the Helm shop manual for testing the HO2 sensor, but I have no experience with it.

Hopefully, one of the experienced Honda Tech's can jump in here and provide some better guidance.
 
Hi CHawk. Issue fixed, it was the O2 Sensor. Bothe engines now have the exact same performance. Have also serviced them and changed the Oil to 10W40 FC-W (still concerned about the bloody thrust washers). Thanks.
 
Glad you figured it out. I wonder why no fault codes were thrown? There should have been a code "1".

As for the thrust washers, you might want to consider moving up to a 25W40 FC-W oil the next time around. I did that at about 1200 hours, and thrust washer was still within spec the last time I had it checked. Best thing you can do is run the engine a frequently as possible.
 
Thanks CHawk, next oil change will be 25W40 FC-W. In summer I use the boat quite frequently but in winter I make a point of running and flushing the engines each two weeks. Do you think this is sufficient? My engines fall within the thrust washer SB. They are still within tolerance. But the engines are serials 170... and have read a post or two stating that people have not encountered premature thrust washer failures on post s/n 170 engines. I guess I won't know until (if) it happens. Meanwhile moved to a thicker oil and will measure flywheel play again next year to check wear rate.
 
Yes, that is a very good regimen for keeping things in good working order.

FYI it takes a very good very precise dial indicator to measure the thrust washer play adequately. However, I've heard that some folks have done it with a good set of feeler gauges. I'm not sure how to do that on the BF 200/225. Hopefully someone more knowledgeable will chirp in.
 
Good result here.Just a comment, O2 sensors can be out of range and fail to throw a code if sending a signal. This is where DrH takes the guess work out of issues since you can monitor the sensor activity to ensure it's working as it should.
 
Diagnostic interface and software. Dr H is original Honda and is more extensive than other cheap diagnostics found on the internet. I purchased Dr H for 350-400 USD to change the instance numbers to have electronic engine indications on the GPS plotter after buying the cables. The cheap interfaces are unable to do this and are more limited but you can buy them for around 100 USD.
 
Do a quick google on "DrH 0635-H0-000AH" and you can see it on the brpdiagnostics web page. I forgot where I bough mine but be aware of the cheap copies.
 
Back
Top