Honda bf150 irregular idlebe

Hi guys,

Just wondering if anyone has any ideas or had heard of this before? I bought a secondhand bf150 with 240 hours (turns out to be 1140 hours according to dr h not happy) but anyway the engine starts perfectly every time without fail but when accelerating the engine runs very rough and the power rapidly surges up an down and I can't get it above 2800 rpm under load and it does the same thing in neutral however will rev up to the limiter. I have taken into the local honda dealer they have so far replace all filters and oils checked fuel pressure re sealed and cleaned vst re sealed induction side and each time they hand it back to me to take it for a spin the same problem occurs. Hoping someone might have had the same or similar problem so I can narrow down what to look for.

regards Robert

Hondadude is the expert on the 150, but I'll jump in for grins. I'm assuming they actually changed the high pressure fuel filter. From what you describe it sounds like maybe an air leak in the fuel lines or filters. Squeeze up the primer bulb until it is tight and look for leaks between the primer bulb and the first filter. If none, keep looking along the entire fuel line to the VST and then on to the fuel rail.

Only questions, at this point...

-Did they do a compression check?
-Did they perform a cylinder drop test?
-Did they check the spark plugs....change spark plugs?
-How come they did not take the boat, at least back it into the water, and make it fail while they watched Dr. H?
-You said that they checked the fuel pressure....but was it ok when the motor failed?
-Did they check to be sure that the ECM recognized that the engine was in gear, when the shifter was in gear? You said that it hit the rev limit when you rev'd it in neutral. Did it tach over 6200 rpm? Normally, if in neutral, the engine will buck (like you are experiencing) if you go much above 3000 rpm.
-Did they check the fuel for water?

By the way 1140 hours is not a lot of hours for the 150 if it was well maintained.

As I said....lots of questions.

Mike

Re: Honda bf150 irregular idle

Hi Mike and CHawk, Thanks for your suggestions and questions. Hope this answers most your questions. This is the report from service agent. First report- Run Honda diagnostic, replace oils, replace oil filter, replace spark plugs, replace fuel filters, replace water pump, check and adjust valve clearances, check thermostat, timing belt, pt&t, check external fuel tank and fuel filter, replace CMP sensor check compressions find and reseal air leak in fuel system from tank to engine Second report- Overhaul induction system re-seal inlet manifold, clean and adjust throttle body. I am unsure whether they did a cylinder drop test, Unsure why they didn't check Dr H on the water they did it all with the motor in the tank, I am unsure about whether ECM registered it was in gear, no water in fuel, as for revving out they said it reach 6000 rpm. Some questions for you should the primer bulb stay hard while running and the next thing they want to do is change the cam chain does that sound right? Thanks for your help so far. Regards Robert chch

1100 running hours nothing for BF150, already done lot of things,now best things to do is run the engine with Dr.H in the sea not in the tank(with load) If you can take out report, just post it here.
I don't know why they want to replace timing chain,
prime bulb will not stay hard while running with load.


wajira

Changing cam chain? Did it jump timing? Is it making noise (like the tensioner is worn)? Other than time on engine....why would they change it?

See more questions. Ask them why.

In all the things that they did, did they record anywhere what they found along the way....like valve clearances too tight/loose? Compression values?

They must have changed the CMP sensor for some reason. Possibly a code that they found.

See.....more questions....

As for the primer bulb...it probably will not stay hard, but should get hard within a couple of pumps.

One thing to try....when the motor is failing...have someone squeeze the fuel bulb to keep it hard and see if that changes anything. If it does, then you have a fuel supply problem.

It sounds like it is time for them to go for a ride with you....as long as the water is fairly close to the dealer.

Unfortunately, this is just like going to the doctor. Check blood pressure, weight, blood, pee in the cup, turn your head and cough, and then he/she puts the rubber glove on....

They have to go over the obvious things. The oils, filters, spark plugs, etc are good to do, especially since it came from questionable service history (only 240 hours ).

It sounds like they did find several things.

Mike

Wow! I must have taken a long time to write my last post. Kept getting interrupted by customers wanting to give me money (and pick up their boats). I did not notice that wajira posted in the mean time.

I does look like we agree on getting the tech on the water with you.

Sorry for the redundancy.

Mike

Thank you all so much I will insist on the dealer to water test it hopefully it will be something simple. Thanks again