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2008 BF150 problem...

T

Tmarine

New member
Hey Guys -

I am new to the forum and new to Honda engines. I have a 2008 BF-150. The engine starts and idles fine however it will not take any throttle - just falls on its face. When I put the engine in gear it will run about 2000rpm. At wot it backfires through the intake.

Today I was tinkering and installed new fuel/water separator filter. Checked the fuel filter on the intake side of the cowl. Everything seems to be passing fuel fine.

Strange part is that I do not have a check engine light.

:confused: Suggestions - Please!

thank you!
 
If this motor is new to you, has it ever run good for you?

Generally, the first things to do are basic, but are just like when you go to the Doctor....weight, blood pressure, heart rate, blood tests.

You need to try to narrow the issue down to something physical like the internals of the engine, electrical like spark, spark plugs etc, or fuel.

Drain the fuel in the vapor separator into a glass jar and see if there are any particles or water in it

There is also a high pressure fuel filter in the vapor separator. You may want to change this at some point.

If you could, checking the high pressure fuel pressure would tell you a lot here. Should be around 40 lbs or so. I am assuming that you do not have the tools to do that.

Does the fuel bulb get hard when you squeeze it a few times? if not that is a problem (probably not the problem)

Run the engine on a hose and do a cylinder drop test. The only way you will be able to do it without Dr. H is to disconnect the connectors going to the spark coils, one at a time. The engine should run slower and/or rougher as you pull it off if that cylinder is firing. Do this one at a time. If you reach one or two that do not change the running of the engine, then those are the cylinders with issues.

Take compression. Put the shifter in throttle only and at full throttle. Compression should be 222 -250 psi and within about 10 -15 psi of one another. If they are all the same, then the cylinders are probably ok. If any of the cylinders failed, then generally you have bad plugs or clogged injectors. I am assuming the valves are ok, based on compression, although that is not always the case....let's hold those off to the side for now.

As you take the spark plugs out, see how they look. Are they different? Some clean, some fouled? Make sure they are the correct plugs...only NGK ZFR6K11 (standard) or ZFR6K-11 (iridium).

Those are a few simple things to do to start.

Mike
 
Hey Mike -

thank you for the response!

the engine is not new to me - I have had it for about 2 years without any problems. This week I took the boat out and about 100 yards from my dock - I knew something was up because it would not get up and go!

its acting like its starving for fuel. When I replaced the fuel/water selector today - it was in pretty rough shape. New housing and filter.

Took the low pressure filter out - had clean fuel and I could blow through the filter. Seems OK.

I have not gotten to the high pressure filter and I have a sneaking suspicion my problem is in there!

I will have to do a cylinder drop test and a compression test tomorrow.

Do not have a fuel pressure gauge ... :(

here are some questions if I may -

1.) what causes the engine to backfire through the intake?

2.) Are there any instructions on taking the lower cowling off?

3.) do I have to take the intake off to get to the high pressure filter or vapor canister... Or does it become accessible once the lower cowling is off?

4.) how do I bleed off the fuel pressure?

5.) is it pretty obvious where the filter is?

thank you!
 
Also put new spark plugs in the machine today as well... They didn't look bad - # 4 was a little black however with the amount of idling - I am not surprised.

nothing changed with the new plugs. Same symptoms.
 
The backfire, may be just the engine responding to a lean condition, if it is fuel starvation.

The high pressure filter and the vapor separator are easily accessible once you get the port side cover off.

To remove, you have to remove the grommet cover #5 first http://www.boats.net/parts/search/Honda/Outboard%20Engine/2007%20and%20Later/BF150AK0%20XA%20/LOWER%20COVER/parts.html

Then remove the various screws #14. You will have to pop the cover over a couple of locating pins along the top edge.

The vapor separator is right there.. http://www.boats.net/parts/search/H...and Later/BF150AK0 XA /LOWER COVER/parts.html

Loosen screw #43 on the cover to the high pressure filter to relieve the fuel pressure. Put a rag over it as you loosen it, so you do not get sprayed with fuel. The hole for that screw is where the fuel pressure gauge gets attached to measure fuel pressure.

Make sure you lube up the o ring on the cover of the high pressure filter, so it does not get cut.

Once you replace the filter, squeeze the fuel bulb until hard and turn your key to on for a few seconds several times to build the fuel pressure. Check for any leaks before you put the side cover back on.

Mike



http://www.boats.net/parts/search/H...BF150AK0 XA /VAPOR SEPARATOR ASSY./parts.html
 
Hey Mike -

thank you again. Took the high pressure pump and filer apart today. Everything seemed to be fine...filter was clean.

Put everything back together and put her back in the water and she runs like a champ!

Not sure if there was trash in the lines or what! She came out of the hole like a rocket - trimmed out I was getting 5700rpms!
 
Glad things are good now. Hopefully, you are right on the trash in the lines.

Did you drain the vapor separator? If so, how did the fuel look?

My gut always hurts when a motor suddenly starts running good without an explanation. I do not like getting a call in the next couple of weeks saying "it is doing the same thing".

I hope all continues to go well.

Mike

Mike
 
Mike - the float bowl was pretty clean - some trash however not like I have seen in my Yamaha high pressure pumps.

My theory is that the high pressure filter - while I could blow through it - was clogged. . . So the new filter and draining the system is what I think solved the problem. The high pressure pump had the most corrosion around it... Cleaned that and the bowl it sits in...

I was quite shocked at how primitive this fuel injection is ... A float bowl!!!!!!?? So the bowl feeds the high pressure pump the pump feeds the injectors! It's like a high tech carb!!

Also - in past times I opened the fuel system I did not cycle the key like you suggested. Perhaps there was air in the system.

Thanks again - ill let everyone know if the issues come back.
 
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