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Honda BF15D starts fine amp then sputters amp dies PLEASE HELP

P

pacificmike

New member
"Hi,

Newbie poster here. H

"Hi,

Newbie poster here. Have a BF15D short shaft manual start tiller. Only about 10-15 hours on it (bought it in the spring from a guy who wasn't using it for the past couple of years). Used as power for my tender. Ran fine until last weekend when it all of a sudden started running rough / sputtering (sounded like it was on 1 cylinder) and then died. Started right up again / ran for a couple of minutes and did the same thing.

Pulled the plugs and both were dry - 1 looked like it had a bit of wear on the ridged connector so I replaced it with the only new spare I had. Same thing. Fired right up and a minute or so after died. Played musical plugs (having only the one spare) to no avail.

Checked the usual. Fuel vent open. Fuel in the fuel filter etc. Thought maybe it was starved for air but all the air intake seemed clear (appears to recycle some exhaust to preheat air going into the carb?)

Back off the water I phoned every Honda service center within 100 miles and no one can even look at it for a couple of weeks (and precious few of those boating weeks left out here). Almost every dealer said the same thing - sounds like the carb has varnish on it from ethanol and needs to be cleaned. Told me the only way to do it properly was ultrasonic cleaning etc.

Didn't seem like the carb would make it sound like it was on 1 cylinder but what the heck do I know. Fed-exd in a new carb which I just installed tonight. SAME PROBLEM.

Recap.

Starts fine with choke on from cold. Runs great for 3 to 4 minutes (choke now off) then sputters and dies. Starts right up again and runs fine for a couple of minutes and then sputters / dies. Starts right up again and again for progressively less time until, while it will start right up, now sounds like it is on 1 cylinder. Spark to both plugs. Lots of fuel. New carb. Lots of flow from the p-hole. Cool water from the p-hole but it is warmer for the few seconds AFTER it stops. Pulling choke while at idle when warm will actually kill it. Dies after this short period of time without regard as to whether it is at idle or WOT.

What the heck.

I'm sure a bunch of you are smarter than me and would appreciate any suggestions / input as my kids are dying to get back out on the boat.


Thanks!"
 
Ok I would have guessed the sa

Ok I would have guessed the same (Carb.) Ok you put on a new carb...same problem. Are you getting Spark? Is there Compression? If you have those 2...then it is def. a fuel issue. Have you checked the fuel pump? Fuel/Water Separator? Is it priming good?
 
"Thanks for the response Bob.

"Thanks for the response Bob. Definitely getting spark. When sputtering away I will back off a spark plug lead and can hear sparks jumping from lead to plug. (I know, probably not the best way to test it). I assume compression is good. Have no way of testing it but it has full power at WOT. Priming is good. When I pulled the old carb there was lots of fuel in it. Excuse my ignorance but where is the water/fuel separator? I see the filter only... I have not checked the fuel pump BUT it has a very consistent pattern of starting no problem and then dying progressively faster as it warms up. Does not seem to be lacking fuel at all.

The fuel is at most 4 weeks old (from when I purchased it that is) Because we boat every weekend and this is a tender I have probably burned about 1 out of the 4 gallons purchased. Because the vent on the tank is left open on the weekends I wonder if condensation would be enough to screw up the fuel?!? I don't know how finicky these honda's are. Had several merc 4 stroke's which didn't seem to care how old the fuel is..."
 
"When it begins to faulter, ha

"When it begins to faulter, have you squeezed the fuel bulb? If you do and the motor continues to run ok, it may be a bad fuel pump or bad fuel bulb. If there is no change, fuel pump and fuel bulb are probably ok.

Check the posting "BF9.9 runs couple minutes, dies" which is a few posts down. Although his is a 9.9 and does not have a manual enrichener, the design of the two motors are much the same. Many of the suggestions could apply to your motor."
 
Squeezing fuel bulb will actua

Squeezing fuel bulb will actually kill the engine when faultering. Tank and fuel bulb are new at the beginning of the summer.

I checked the other posting. Thanks. Do you think it could be the coil?
 
"Squeezing the fuel bulb shoul

"Squeezing the fuel bulb should not kill the engine. Normally, I would say carb problem...but you have a new carb...I assume carb is bolted on tight and the manual enrichener was tight on the carburator.

Drain carb into a glass jar to see if there was any water. 40% to 50% of runability issues I see have water in fuel

Oil level at proper level or at least somewhere midrange?

Spark plugs...NGK CR5EH-9?
Both plugs fire at the same time through the same circuit. It could be a bad coil as you asked, could be a bad plug. I think you changed those out already. I have not seen a 15D coil fail yet, however, anything can fail.

Does the motor faulter when you pull either one of the spark plugs?

You said you have already checked venting.

How warm does it feel at the head? Pull the thermostat and try running without it. It is on the port side of the engine under a black plastic cover held on with two bolts (need a 10mm socket). Thermostat could have trash in it or be stuck closed. It should only take a couple of minutes to try.

A compression test would be good if you could borrow a gauge. There could always be some kind of valve issue. A compression test normally will help to diagnosis.

There is a hose from the valve cover that goes to the carburator. Pull the hose off of the carburator. Do you feel air pulsing out of the hose when the engine is running? If not, there could be an issue with the one way valve on the valve cover. Essentially, it is like a PCV valve in a car. If no pulsing, there could be too much crankcase pressure to run the engine. Replacing the valve cover could fix that.

As you could see, there are scores of things that can effect the running of the engine. When this is all said and done, it will probably be something very simple."
 
"Thanks HondaDude. I drained

"Thanks HondaDude. I drained the carb and checked for water. Can't see any. One quick question - how quickly will the new plugs (yes they are NGK CR5EH-9)foul if there had been water in the fuel? Wondering if I should put another new set of plugs in.

There is air pulsing out of the hose coming from the valve cover. The head gets warm but does not feel like it is overheating. I will pull the thermostat this afternoon and try that. Does the engine reduce power electronically if it thinks it is overheating? because that might make actually make sense.

Thanks again,

Mike"
 
Pulled the thermostat and no c

Pulled the thermostat and no change. Ran for 3 minutes then stalled. Ran another minute or so and stalled. Now stalls every 45 seconds to a minute like clockwork.
 
This afternoon

1. Drained

This afternoon

1. Drained Carb
2. Fresh Fuel
3. Yet another new set of plugs
4. Check air coming from valve cover hose to carb
5. Pulled thermostat
6. Double Checked spark
7. Starting to question my sanity

Any other thoughts?
 
"Yes, the engine will turn its

"Yes, the engine will turn itself off like pulling the safety lanyard if it gets too hot. There is a sensor on the port side of the head between the spark plugs. Usually, it will not restart right away though.

When you restart after a failure, do you have to squeeze the fuel bulb? Pull out the choke? ...to get it started again?

It would be good to know if there is spark immediately after it fails? Do you have a timing light to put on one of the plug wires so you can see what is going on sparkwise?

Also, while the motor is running, wiggle the wires around the motor. Concentrate on the ones that disappear under the flywheel and the ground connections.

One other connection is a fairly large connector (it is usually white) that plugs into the powerpack on the front of the engine. Push/pull, wiggle, etc to see if it more quickly stops the engine. Disconnect the connector from the powerpack and reconnect several times to clean any potential connection problems.

This will be easier to find if we can determine that it is electrical or fuel related."
 
"This is a really interesting

"This is a really interesting problem. I'm no expert, and have no experience with that engine. However, given all that you have done and given what you are describing, I would start focusing on electrical. Start with the coil. I know you said you have a strong spark, but something is breaking down at a constant interval. Borrow, beg or steal a timing light and watch what happens when it starts failing. If you see irregularities, change the coil.

From an electrical point of view - first check all connections - something could be loose. Especially check all ground connections right after failure. It is possible that the initial heat up is just enough to make one of the connections fail. I'm not sure of your fuse situation on that engine, but would pull them all, clean contacts, reinsert and pull several times to clean mating contacts. Thinking of fuses, if they are the blade type, occasionally they will fail without the telltale break in the wire line. Take a spare and check each one.

And a final thought - what is the state of the ground on your battery. Pull it, clean it, and reconnect."
 
One of the grounds to pay clos

One of the grounds to pay close attention to is on the port side of the engine about a 1/4 way back near the base of the engine. It is a small wire that is the ground for the power pack. I have found one in the past that the wire broke inside the insulation and made just enough contact to run sometime. Your wiggle test should find it if it is the problem.
 
"Thanks Guys. Engine starts f

"Thanks Guys. Engine starts first pull every time no choke or bulb squeeze ever required. I suspect that something electrical is failing when it is getting warm. Checked the ground wires and they look good. No corrosion. I have wiggled every wire that I can get at, pulled the plug on the power pack (looks factory fresh). Wiggling wires does not seem to make any difference. I will try to get my hands on timing light tomorrow. If I back one of the plug leads off a bit I can hear consistent interval spark until the moment it dies. I am wondering if my problems could be the coil. The warmer it is the quicker it dies and although it restarts immediately every time it runs rougher when under load once restarted (after it is warm that is).

Does anyone know the telltale signs of a failing coil?"
 
"Don't go changing coils e

"Don't go changing coils etc until you do some measurements. There are two pickups under the flywheel, power pack, oil and overheat sensors, and safety switch besides the coil.

The first thing to do if we are going after an electrical issue is to disconnect the safety switch leads. They are the black/red and black leads coming from the tiller handle. The connectors are located in the holder on the port side front of the engine, next to the power pack. Just pull both connections apart and leave them hang.

What kind of voltmeter do you have? Depending on what you have, I will first have you connect it to the primary of the coil to watch what is going on while watching the timing light. If you have the old time meters with a needle, it will read faster. The readings will not be accurate, but will work for this situation.

Basically, you will test with the meter at different locations. If the voltage continues to read but falls off slowly when the engine is stopping, the component is probably ok. If the voltage cuts off immediately, we are getting in the ballpark.
It will probably be a case of eliminating the good and we are left with the bad.

One last question...is your oil pressure light coming on?"
 
reminds me of an engine i worked on some time ago, fuel pickup was partially blocked. each time engine died dirt would float away from pickup, only to be drawn back by suction after a couple of minutes. just a thought.
 
I also have the exact same problem which is becoming frustrating and costly. Please post the solution if you found one. I do know that I have the cleanest carb in the world and that honda did a recall in on the fuel chamber of that motor.
 
I worked on a friends 15 last night,He was having same symtoms, after going through all the systems the only thing we could find was the water pump impeller was missing some fingers. There was not enough water flow at idle over heating the motor a causing the temp sensor to shut down motor. An easy way to tell if it is a pump issue is the Telltale water stream is very slow.
 
Hondagirl,

Welcome to the forum.

Start a new thread and state your case. This thread is so old and long your issue might go unnoticed by someone that could help you.

Tell us exactly what it's doing and what you've done to try and correct it. It sounds as if you've done quite a bit but list it out so that something you say might ring a bell with someone.

Frame number and year model is also helpful.
 
Re: "Hi, Newbie poster here. H

pacificmike said:
"Hi,

Newbie poster here. Have a BF15D short shaft manual start tiller. Only about 10-15 hours on it (bought it in the spring from a guy who wasn't using it for the past couple of years). Used as power for my tender. Ran fine until last weekend when it all of a sudden started running rough / sputtering (sounded like it was on 1 cylinder) and then died. Started right up again / ran for a couple of minutes and did the same thing.

Pulled the plugs and both were dry - 1 looked like it had a bit of wear on the ridged connector so I replaced it with the only new spare I had. Same thing. Fired right up and a minute or so after died. Played musical plugs (having only the one spare) to no avail.

Checked the usual. Fuel vent open. Fuel in the fuel filter etc. Thought maybe it was starved for air but all the air intake seemed clear (appears to recycle some exhaust to preheat air going into the carb?)

Back off the water I phoned every Honda service center within 100 miles and no one can even look at it for a couple of weeks (and precious few of those boating weeks left out here). Almost every dealer said the same thing - sounds like the carb has varnish on it from ethanol and needs to be cleaned. Told me the only way to do it properly was ultrasonic cleaning etc.

Didn't seem like the carb would make it sound like it was on 1 cylinder but what the heck do I know. Fed-exd in a new carb which I just installed tonight. SAME PROBLEM.

Recap.

Starts fine with choke on from cold. Runs great for 3 to 4 minutes (choke now off) then sputters and dies. Starts right up again and runs fine for a couple of minutes and then sputters / dies. Starts right up again and again for progressively less time until, while it will start right up, now sounds like it is on 1 cylinder. Spark to both plugs. Lots of fuel. New carb. Lots of flow from the p-hole. Cool water from the p-hole but it is warmer for the few seconds AFTER it stops. Pulling choke while at idle when warm will actually kill it. Dies after this short period of time without regard as to whether it is at idle or WOT.

What the heck.

I'm sure a bunch of you are smarter than me and would appreciate any suggestions / input as my kids are dying to get back out on the boat.


Thanks!"
Click to expand...
I have had same problems with a 1995 8 hp Honda, I have it hooked into the main fuel supply of the boat with a water fuel separator , I have yet to change the separator, but smaller engines are more susceptible to bad fuel. my problems however were due to the sensors I was not running enough oil in engine which has a shutdown sensor , I changed oil and it ran great. older Hondas also had a badly designed water tube which can in salt water start plugging up which can cause overheating too ergo another s
shut down
 
SOLVED! It's a broken Impeller, (water pump) it's just plastic and over time the fins that push the water deteriorate > it'll start fine but after 3-5 minutes it starts to sputter and overheats > heat sensor shuts down the engine to prevent catastrophic failure! > SO DO NOT UN-HOOK HEAT SENSOR to trouble shoot! > It will start back up immediately but shuts down quicker and quicker cuz it's hot already > Soon as the engine cools off it will cycle through same issues!

I'm kinda new at Outboard motors but not new to Mechanical stuff! It's actually easy to fix once it's identified. Tilt engine to max height > Shift into Neutral > Unhook transmission linkage (10mm nut on adjustable rod @ front of shaft ⅔ of way down shaft) > Loosen 4 Bolts to approx ⅜" (do not remove them yet) to drop lower shaft assembly at Prop, 4- 10mm bolts / 2 on each side of Shaft PLUS one more Tricky little bolt at very bottom... on mine... easy to miss so DON'T GO POUNDING on it just yet... NOW get your rubber mallet and tap on all 4 edges to break seal of lower prop shaft assembly > NOW... take ALL 5 BOLTS totally out > FIRMLY GRIP the Prop Shaft assembly and GENTLY wiggle with downward pressure and VOILA... You will need a New Impeller and possibly the Housing that holds it in place... Mine got pretty chewed up!

This Video helped me to identify how to get at the Impeller
https://youtu.be/j8mdRQGEkO8 > this Video is of an older unit and some things are different on Newer Models but essentially the same > JUST MAKE SURE TO LOOK AND SEE IF YOURS HAS THAT 5th BOLT AND REMOVE IT!

Here's another Vid with a NEWER Honda like BF15D, just bigger I think a 30HP. He's just doing a thorough Annual Service... Also very helpful... https://youtu.be/p1ycWZuPvyE

Happy water trails to you!...
 
Last edited:
Re: "Hi,

Newbie poster here. H

SOLVED! Broken Impeller Fins causes overheating and kicks the Overheat Sensor on > SHUTTING ENGINE DOWN > when it cools off it's Rinse and Repeat!

SAME issue on mine... Saw your thread and did a quick assessment and after cleaning Fuel, Lines and Filter... I noticed the Prop Shaft Housing midway down was hotter than a firecracker!

Took it apart and IT IS A BROKEN IMPELLER (water pump) it's just plastic and over time the fins that push the water deteriorate > it'll start fine but after 3-5 minutes it starts to sputter and overheats > heat sensor shuts down the engine to prevent catastrophic failure! > SO DO NOT UN-HOOK HEAT SENSOR to trouble shoot! > It will start back up immediately but shuts down quicker and quicker cuz it's hot already > Soon as the engine cools off it will cycle through same issues!

I'm kinda new at Outboard motors but not new to Mechanical stuff! It's actually easy to fix once it's identified. Tilt engine to max height > Shift into Neutral > Unhook transmission linkage (10mm nut on adjustable rod @ front of shaft ⅔ of way down shaft) > Loosen 4 Bolts to approx ⅜" (do not remove them yet) to drop lower shaft assembly at Prop, 4- 10mm bolts / 2 on each side of Shaft PLUS one more Tricky little bolt at very bottom... on mine... easy to miss so DON'T GO POUNDING on it just yet... NOW get your rubber mallet and tap on all 4 edges to break seal of lower prop shaft assembly > NOW... take ALL 5 BOLTS totally out > FIRMLY GRIP the Prop Shaft assembly and GENTLY wiggle with downward pressure and VOILA... You will need a New Impeller and possibly the Housing that holds it in place... Mine got pretty chewed up!

This Video helped me to identify how to get at the Impeller
https://youtu.be/j8mdRQGEkO8 > this Video is of an older unit and some things are different on Newer Models but essentially the same > JUST MAKE SURE TO LOOK AND SEE IF YOURS HAS THAT 5th BOLT AND REMOVE IT!

Here's another Vid with a NEWER Honda like BF15D, just bigger I think a 30HP. He's just doing a thorough Annual Service... Also very helpful... https://youtu.be/p1ycWZuPvyE

Happy water trails to you!...
 
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