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2005 BF135 with 300 hours will crank but not start. Starts briefly with Starter Fluid.

I

islandwoman

New member
Let me start by saying that I'm a woman with no mechanical background but I am good with my hands. So go easy on me if I use the wrong terms. There are no honda mechanics around us so I'd like to try to help my husband fix this issue. We bought a 21' flats cat with this 2005 BF135 on it in June of 2022 from a dealer that had just done a lot of work to this motor and had it in running condition at the time of purchase. Last time the hours were checked at that time, it had 250 hrs on it. We estimate that we could not have put more than another 50 hours on it so this motor has maybe 300 hours on it max. So we're speaking about a fairly fresh motor here... Only been used on saltwater though... In May of 2022 the marine dealer we bought the boat from had done the following work to the bf135 in question: "Changed engine oil and filter. Replaced in-line fuel filter and water seperator filter. R&R gear case and replaced water pump impeller and changed gear lube. Replaced spark plugs. Replaced bilge pump. R&R thermostats and clean, replaced thermostat housing and gasket. R&R vapor separator tank, clean out and replaced fuel pump. Replaced oil filter. R&R fuel injector and sent out for clean and flow test." We used it maybe 4 times and from the first use we had that surging problem that everyone talks about but it would idle fine. My husband thought that it needed to work through the issue by running the motor out. Fast forward to now. The motor will on crank and will start for a few seconds when squirted with starter fluid but it will fail to ever reach an idle state. I checked the code by using a service connector shunting device and the MIL just stays on. Doesn't blink at all. Lead me to believe that the ECM was bad so I bought a known good one and swapped them out. Same problem as before and MIL still just stays on when looking for codes. So that has lead me back to believe that maybe there is a short to the MIL and that we should focus on the obvious symptoms. The motor isn't getting fuel. Given that it just had the fuel system cleared by a mechanic, I am not sure what could be wrong. It acts fuel starved. From the first time we ran it after all these repairs were done it would go into an almost limp mode but would always be able to get us back to the dock. It will not start at all now. Help!
 
With a fuel problem, start by checking the fuel for water, drain the water separator into a clear container and let it sit for a while and see what settles out in the bottom. This will start your assessment process by confirming your fuel source is clean.
I’m not computer knowledgeable on these outboards but I’m sure someone who is will reply soon.
 
Will do. New information has come to light that a heavy mix of seafoam was being run through the fuel when the boat was last running 3 weeks ago. Boat was running fine on muffs and then it acted like it was out of gas, wasn’t, and abruptly cut off. Leads me to believe that maybe the spark plugs got wet and are likely fouled by now. Ordered a set of new plug. In the meantime, I’ll drain the fuel separator and take out the old plugs to see if my suspicion is confirmed.
 
The engine isn’t likely get fuel because the ECM(computer) isn’t allowing the high pressure fuel pump to turn on due to the MIL light being on. When you turn the key to on, not start, you should hear the fuel pump run for 3-4 seconds. I don’t own a large Honda outboard but I would suggest you check all electrical connections and wires for corrosion/breaks. If you don’t have a genuine Honda service manual I would suggest you purchase one, it should have all the electrical specifications and how to test with a multimeter. If your issue is fuel related then the service manual will have testing procedures to follow.
 
I do hear a noise that I assume is the high pressure pump when I turn the key to the on position. Both with the original and known-good ecm. So I guess there could be a short to the MIL itself. Would that not allow the motor to start up? I do have a Sevice manual from the previous owner. All the fuses are good. All the electrical connections and wiring I can see on the motor looks fine. But haven’t checked anything with a multimeter yet.
 
If your fuel pump is kicking on then MAYBE the ECM is preventing spark to the spark plugs due to the MIL light being on. Any fuel getting to the VST? Are the plugs wet after cranking? IMHO I think firstly you need to determine if your issue is electrical or fuel delivery. In the service manual there will be a troubleshooting section, good place to start. There are a few Honda gurus on this forum, they are fairly active and I’m sure they will be able to help.
 
Hi,
Ìf at all possible, you should probably take this to someone that can plug in the diagnostic tool and read the live data. I realize that may not be feasible for you but I had to suggest it.

Aside from that, I would also suggest that you STOP using starting fluid for troubleshooting and use propane gas instead. The reasons are many:

Starting fluid (ether) can and DOES cause engine damage.

Propane is APPROPRIATE for this and is easy to use. Most people will ignore this advice and many will pooh-pooh it or say that it's too hard to do or is dangerous. It is NOT dangerous! Although, I get that people get intimidated because they aren't familiar with the process. Pretty much ANYONE (including women!) can MacGiver a propane test set up using a small bottle of propane, a plumbing torch, and a bit of rubber hose to help direct the gas into the throttle body. About $40 or $50 last time I looked.

The propane test will KEEP YOU FROM GUESSING if it's a fuel starvation problem or an ignition problem.

I will happily walk you through it if you are interested at all.

Good luck.
 
After considering your symptoms some more, it occurs to me that you should probably look into the operation of your LAF (Lean Air Fuel) sensor. Otherwise known as an O2 or Oxygen sensor. See item #7 in link below.

https://www.boats.net/catalog/honda...vin-barj-1100001-to-barj-1199999/exhaust-pipe

Honda has had many issues with those and they will cause the type of surging that you described. Although, I don't know if a bad one would cause the no start you're now having.

Many people simply swap the O2's out and see what happens. Expensive though.

If you're adventurous, the mid 2000 Honda Accord used these sensors and finding a "match-up" at a car dealership might be cheaper. Being nice to the parts counterman when he's not busy doesn't hurt to see if they're willing to do a little digging. Take yours to them and see what happens.

I believe also that this uses a heater circuit for that sensor and there is a relay in the fuse "box" that feeds the heater coil. See item #8 in link below.

https://www.boats.net/catalog/honda...barj-1100001-to-barj-1199999/fuse-box-relay-1

Be VERY careful hooking up a car dealer sourced sensor (or any sensor really) and make sure the wires to the heater coil match. Hooking the heater power volts into the signal portion of the sensor will likely destroy the sensor and might damage the ECM. A quality digital ohmmeter is a good tool to use to compare and verify resistances between sensors prior to installation.

Good luck.
 
Forgot to mention that it's not unusual for there to be more than one issue attacking you via your outboard. It happens with machines of all kinds and can have you going in circles. Just keep the possibility of that in mind as you go forward.

This issue does sound like a two problem case to me and I still would recommend a propane run test to prove she'll fire the ignition reliably but I've been wrong a couple or three times before.

Sorry for the novel but I'm just a wordy nerd trying to help.
 
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