2009 BF50 Hard Start Issue

Recently my 2009 BF50 (EFI) with about 700 hours has been hard to start. It will start, but in order to getting running to need to advance the throttle to keep RPM up once it catches. Not normal...

Currently if in neutral with no throttle it will turn over and die immediately. Bulb pressure seems ok for what it is worth.

Once running it runs smooth, and will restart no problem when warm. The no start is only when cold after sitting for a day.

Any thoughts/ info would be appreciated. I would like to try to diagnose and fix myself, but worst case there is a good Honda mechanic locally I can drop it off to have repaired.

Thanks in advance for any help!

Pointer18 said:

Recently my 2009 BF50 (EFI) with about 700 hours has been hard to start. It will start, but in order to getting running to need to advance the throttle to keep RPM up once it catches. Not normal... Currently if in neutral with no throttle it will turn over and die immediately. Bulb pressure seems ok for what it is worth. Once running it runs smooth, and will restart no problem when warm. The no start is only when cold after sitting for a day. Any thoughts/ info would be appreciated. I would like to try to diagnose and fix myself, but worst case there is a good Honda mechanic locally I can drop it off to have repaired. Thanks in advance for any help!

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I'm most familiar with the carbed engines, but it seems to me like there is a filter on the IAC valve that can plug causing the idle speed to mess up. That's where I would start here anyway. For an idea of what/where on the IAC valve, see #10 here: https://www.boats.net/catalog/honda...00001-to-bbej-1399999/inlet-manifold-injector

This also sounds like it could be a small vacuum leak. If you don't find a problem with the idle air valve you could try "spritzing" some carb cleaner at the intake manifold gaskets (item 7), the map sensor oring seal (item 13) and the throttle body gasket (item 8).

If the engine speeds up and smooths out it is probably a poor seal in that location.

Good luck.

Thanks to you both for the ideas...

One other thing the engine is doing.... when I start it cold it turns over and dies. But if when starting it I hold the key over for another 3 seconds after it fires up, the engine remains running. Makes me think this may be fuel pump related, and possible the low pressure fuel pump is not holding the pressure int he line between uses.

Any thoughts?

Thanks again for the help troubleshooting!

I don't know but you say the primer stays hard and that would seem to indicate that the low pressure system is "full". Are you cycling the ignition to "on" and waiting for the high pressure pump to run or just going right to "start"?

You could try cycling the key to "on" and listen for the high pressure pump to run for a couple of seconds. Don't engage the starter.and give the bulb a squeeze then do the same thing again. Then try starting it and see what happens.

Have you tried cleaning the IAC screen yet?

You might go back and look at the. spark plugs and ignition coil connections. Tight spark plug boots and a new set of NGKs can sometimes work wonders. Always smear a small quantity of DIELECTRIC (tune-up) grease inside the inner edges of the plug boots to keep moisture out.

Be very cautious about keeping the starter motor "helping" the engine to keep going after you hear it fire. You could easily damage something doing that.

Good luck.

Thanks JGMO for all the tips...

I was on the boat yesterday and noted a few things.

When key turned I hear a pump cycle for ~3 seconds
Bulb is pretty soft and I do not think it is holding pressure. I pumped it in order to get firm again, but this did not help starting.
Engine is very hard to start, but once running it is smooth.
wiggled all sparks plugs and seemed like good connection.

One other thought was related to the kill switch, and if that could be some weird factor?

Also, if the low pressure fuel pump fails, would that possible lead to the potential lack of fuel to get the engine started? Seems once it is running it may be just creating a vacuum to pull fuel through and feed the high pressure fuels system?

Hauling boat this weekend and will be much easier to trouble shoot in driveway.

Thanks again. any further thoughts are welcomed.

Update.... Ended up being a bad ignition switch. Thankful the engine is in fine shape, and the Honda dealer I went to advised the switches fail pretty often if exposed too much. Plan to make a console cover that should protect it better moving forward.

Funny thing was I focused so much on the engine fuel system, spark, etc I did not think about the switch. luckily a fairly inexpensive repair to replace.

I’ve gotten in the habit of applying Dielectric grease on my ATV to all electrical connections and have started with my outboards. I use the connectors with the plastic covers that help keep grease in and water out.

That is good news Pointer18!

Happy to hear you got it sorted out and thank you for following through and updating your post with the FIX.

Fair weather to ye!