Honda BF15A Outboard Problems

[pickardjw]

Having issues starting my 1997 Honda BF15A outboard. The trailer frame broke late July 2024 and I limped it to Wenatchee where it stayed until mid-March of this year. Did not do any winterizing (I know, shame on me). When we swapped the boat onto the new trailer in March it started and seemed to run like normal but died after several minutes.

Got around to messing with it yesterday and it's not turning over. Not a mechanic so I'm researching as I go. Here are the steps/observations so far:

1. Fresh gas
2. Oil change
3. Pulled carb and cleaned it. Could potentially need more extensive cleaning.
4. Spark plugs checked, appear to be in decent shape but ordered new anyway.
5. Fuel line bulb pressurizes before starting, then after attempting to start is less pressurized.
6. Fuel filter was changed 2 years ago, ordered another.
7. Engine only tries to turn over with a little starter fluid.

Should I go ahead and replace the fuel lines as well? They haven't been replaced for at least the 4 years I've had it. Not sure if there's an easy way to test that but I assume I could pull the intake to the carb and pressurize the bulb?

I'd like to fix it myself, but the motor hasn't seen a professional in who knows how long so if that's a better option anyone got a Honda tech in the south sound area they like?

Edit: kill switch was inserted, so that's not the culprit. Though I have made that dumb mistake before.

[CP]

In your video it is turning over but it isn’t firing.  You need three things for an engine to run:
1.   Fuel
2.   Air
3.   Spark

“7. Engine only tries to turn over with a little starter fluid.”
It fires with starter fluid?

Are the plugs firing?  Check them by pulling the plugs, connect to its wire then turn the engine over while grounding the base of the plug to the engine.  Sparking?  Is the spark strong?  Use rubber gloves when doing this, or 

Fuel – drain carb bowl(s) – Is there fuel in them?  Is it fresh?  Do the bowls refill when you pump the bulb?

Air – Is it sucking air into the carbs while turning over?

Once you narrow it down it will be easier to pinpoint the problem.

[pickardjw]

In your video it is turning over but it isn’t firing.  You need three things for an engine to run:
1.   Fuel
2.   Air
3.   Spark

“7. Engine only tries to turn over with a little starter fluid.”
It fires with starter fluid?

Are the plugs firing?  Check them by pulling the plugs, connect to its wire then turn the engine over while grounding the base of the plug to the engine.  Sparking?  Is the spark strong?  Use rubber gloves when doing this, or 

Fuel – drain carb bowl(s) – Is there fuel in them?  Is it fresh?  Do the bowls refill when you pump the bulb?

Air – Is it sucking air into the carbs while turning over?

Once you narrow it down it will be easier to pinpoint the problem.

Correct, it only turned over with a short spray of starter fluid. Would not turnover without it. Fully choked. I primed with the bulb a few squeezes until the bulb was well pressurized but was nervous about flooding.

I'll test the spark plugs, new and old. And watch a video on how to do it safely, haha.

I pulled the carb to clean it before trying to start it. There was a small amount of fuel in the bowl but not much. I'll check it again since it's been primed since. Carb seemed very clean, no grime in there at all though I have noticed a drop in RPM.

How would you check for air intake to the carb?

I appreciate the help!

[CP]

How would you check for air intake to the carb?

Remove the plugs and air filter, cover the intake with your hand while cranking the engine.  You should feel the air getting sucked in.  Also, you can cover the plug holes with a clean rag while cranking.  You should see the air pumping out and the rag should get wet if you do this long enough. 

I assume that you don't have a pressure gauge but if you do, check the cylinder pressure.

[CP]

Per Google:

Honda BF15A - compression test, 95psi on top 125 on the other

[Sandberm]

 Take the carb off again and go through it with a fine comb. Check and clean EVERY little pin hole and passageway. Newer motors have such tiny passageways for air and gas to go its easy to get plugged and hard to see.

Were you running non ethanol before you parked it?

What kind of fuel filter does it have? One of those plastic ones that you can easily see what's plugging it?

[pickardjw]

Take the carb off again and go through it with a fine comb. Check and clean EVERY little pin hole and passageway. Newer motors have such tiny passageways for air and gas to go its easy to get plugged and hard to see.

Were you running non ethanol before you parked it?

What kind of fuel filter does it have? One of those plastic ones that you can easily see what's plugging it?

I'll pull the carb and go through it more thoroughly. It's a 1997, so not sure if that counts as "newer". Here's a pic for reference.

Unfortunately, standard 87 octane fuel.

Fuel filter is the plastic, semi-transparent one below. It had fuel in it and no apparent blockages but just checked with a flashlight. Didn't pull it.

https://www.amazon.com/Honda-16910-ZV4-015-Fuel-Filter/dp/B007TJWH9C/ref=sr_1_1?crid=OT3V09KPL673&dib=eyJ2IjoiMSJ9.PWQ3iI873YD-UECoHPbBqf_BYnxiXYcbRKGhjenfTq-RiKzCZ-qLfgK8_R7SZccvUHCNOZN2tD9U18hDmTdRPAPSNz-SG8OopDqROqNla4YR0OWwpI5uz6FcoXn-KYJ_yMOfS1LrXgv-LHjcIe70xIjzpCbzk5Q6pBb4WtKYscBcXtVGi1JdHRaL2D_bvZH2MJlMxRRewlT93gzet7HvwhlqpYGyCVREoYBOs-Z9DxE.d2aeeLfrZ6xRhVBiJlZaQtEzH5qL_bU41YBWARyOolE&dib_tag=se&keywords=honda+bf15a+fuel+filter&qid=1748889380&sprefix=honda+bf15a+fuel+filt%2Caps%2C264&sr=8-1

[Sandberm]

Huh, not good on using standard gas. I'll tell ya story about my boat engine.

So when I first got my boat brand new in 01 dad and I ran regular gas in it for probably the first 9-10 years we had it. We went fishing often enough that we really didnt have too much problems because the gas was fresh enough. But, and i just found this out last spring as my boat started having intermittent problems of not running well is that the inside of the fuel line that runs from the tank to the motor was breaking down and sending flecks of what looks like laminate into the fuel filter, perhaps past it and constantly clogging stuff up because of past ethanol gas use (or whatever) as it really doesnt matter the cause.

I can see in your picture that where the fuel line plugs into the front of the motor is a hose clamp holding the inlet fitting on. Cut the hose right behind that fitting and use the bulb to pump gas into a clear jar to see if any contaminates come out and do a visual inspection looking into the end of the hose to see if it is breaking down. If it looks good just slide that fitting back on.

Not my picture but it can look something like this. https://www.bbcboards.net/showthread.php?t=22490



Worst case scenario you may need to go through the whole fuel delivery system to check for blockages/damage due to ethanol gas or whatever.

I also one time had the tube that extends down into the tank to draw gas out had rotted/fallen off and thus i was not getting any gas to the engine.

And the final thing I did was to order NGK sparkplugs directly from the NGK website. Its my understanding that NGK is the most counterfeited spark plug sold so I went directly to the source as i have heard knockoff spark plugs can give problems too.

[pickardjw]

Working on the motor now. Replaced spark plugs and it fired up first try. Don’t necessarily think that was the culprit though.

Re-cleaned the carb and pulled the jet nozzle. Sprayed it out and carb cleaner was spraying out of the ports without any apparent blockages. Reassembled and the motor fired up quick but eventually died.

Wasn’t peeing so I cleared that line, it had quite a bit of gunk in it. Fired up again and started peeing immediately so I think that’s fixed.

The carb is leaking gas, so I guess I gotta figure that out.

I did notice the bulb was pretty deflated after it died so maybe a fuel line blockage still?

Edit: cleaned out the fuel line from tank to motor. No obvious issues. Reattached and the motor fired up and stayed running for a solid 2 minutes before dying. I noticed the carb was not leaking initially but one it started to leak the motor died.

[ASHQUACK]

Working on the motor now. Replaced spark plugs and it fired up first try. Don’t necessarily think that was the culprit though.

Re-cleaned the carb and pulled the jet nozzle. Sprayed it out and carb cleaner was spraying out of the ports without any apparent blockages. Reassembled and the motor fired up quick but eventually died.

Wasn’t peeing so I cleared that line, it had quite a bit of gunk in it. Fired up again and started peeing immediately so I think that’s fixed.

The carb is leaking gas, so I guess I gotta figure that out.

I did notice the bulb was pretty deflated after it died so maybe a fuel line blockage still?

My bet would be a bad line allowing air into the fuel system. And just because they're new doesn't mean they're good. If you lose pressure in the fuel line you have a leak somewhere in it.

[CP]

Sounds to me like it is running out of gas.  Carb, lines, or pump, maybe all 3. 

Try pumping the fuel bulb when it slows down.  If it picks up speed again that points to a fuel pump, or maybe a carb float problem.  I’d rebuild the carb just because, it’s leaking anyway.

Fuel tank maybe?  Is it venting? 

[pickardjw]

Sounds to me like it is running out of gas.  Carb, lines, or pump, maybe all 3. 

Try pumping the fuel bulb when it slows down.  If it picks up speed again that points to a fuel pump, or maybe a carb float problem.  I’d rebuild the carb just because, it’s leaking anyway.

Fuel tank maybe?  Is it venting?

I did try pumping the bulb when it slowed down. Didn’t have any effect. I can look into some carb rebuild instructions. Not sure how much deeper into it I can get, already had it apart 3 times. Couldn’t pinpoint where it was leaking from. Seemed to just be covered all over in gas on the top and sides, doesn’t show up well on video.

Fuel tank should be venting, I had the cap partially open.

I feel like I have enough info to bug the outboard repair guy next to my jobsite. Think he’s a mercury guy but it would be very convenient to bring it to him if I can’t fix it.

[CP]

You can get a replacement carb if you don't want to tackle the rebuild.  They aren't too expensive. 

But that's about the extent of my shade tree "knowledge".  The Merc guy should be able to help. 

Good luck!