BF130 hard to start.

I have twin honda 130's on my boat. The one giving me trouble is a 2004. I fish in Alaska and use this boat almost exclusively in the winter. This outboard won't start without hitting it with a shot of starting fluid if temperature is below 50, which it obviously is all winter. Once started it runs and idles great, it will even restart as long as engine temperature is still warm.

I am friends with the owner of the local honda shop and have tried all suggested fixes and even took it into the shop for their mechanic to work on and still have not found the cause. I'll try to list all we have tried, but its been going on for a few years and are not all fresh in my mind. They have been very helpful, but I think i need outside help.

We have replaced all filters and vapor separator. Have checked both the electrical and mechanical fuel pumps. Checked entire fuel system, fuel rail, injectors, etc. The motor has good compression, is getting fuel, and has spark, yet won't start. I have also replaced a number of sensors and relays with no change in condition. I'm sure I'm leaving a few things out.

Ive been told numerous times that there is nothing temperature sensitive on the motors. The only possibility is something bleeding out and loosing pressure over time. Yet regardless of time it sits, if you pull it in a 70 degree shop it will fire right up. Park it outside in 20 degrees for 2 hours and it won't start on its own.

any suggestions on what to check next?

thank you

Is the starter spinning the engine fast enough? It's critical.

Yes, the starter turns the motor over considerably faster than the functioning motor. The starter was recently replaced as I burnt it up trying to start it without the use of starting fluid.

Ok.

When you power the ignition switch to the on position do you hear the fuel pump cycle?

Yes, I can hear the fuel pump cycle. We have tested both electrical and mechanical fuel pumps. Have even pulled injectors and physically watched them spit fuel to confirm its getting through the entire system.

You will have to start with checking fuel pressure, with a gauge. You will need a banjo fitting screw with a port on it to replace the one on your engine to attach a gauge where the HP fuel line attached to the rail.

I have a fuel pressure guage but not the proper fitting. I also have a 3rd bf130 for parts and have tried swapping fuel pumps without a change in condition. If you think it's still necessary to chech fuel pressure I'll look for a fitting.

thank you

A little additional information. When the problem first began it would sputter and die several times before starting. Then it slowly got worse until it wouldn't start at all on its own.

As a marine mechanic, if the compression is good, I would start with a check of the fuel pressure and then spark strength. These are the things I would want to verify with my own eyes, no disrespect to your friend who owns the Shop.

Ditto what Chris said.

If that checks out...

Try putting the shifter in throttle only and advance the throttle at least half way....then try to start it.
Be ready to pull the throttle back, in case it does start. Normally, you should not advance the throttle.

It is possible the IAC is not functioning correctly and it may need more air (I know you used starting fluid and it seems like it would need more fuel)....

At least give it a try.

If it starts up, you can "borrow" the IAC from the other engine to check for sure.

The ECM and one of the temperature sensors (along with a few other things) tell the IAC what to do. So, it could be the ECM or a temp sensor.

In general, good NGK spark plugs and good fuel are a must with this engine.

Mike

Thanks for the replies, I have swapped the IAC between the 3 motors as it seemed the most likely solution without change. Honda supposedly checked the ECM and said it was good. Advancing the throttle position doesn't help and I have swapped temperature sensors. It also has brand new NGK plugs.

i have not been able to locate a proper fitting for my fuel guage yet but will keep looking. A visual inspection shows both motors spurting equal amounts of fuel the same distance and since I have already swapped fuel pumps without change I'm thinging its something else.

how many temperature sensors are there? I believe there were 2 I swapped, but that was a year ago. Been chasing this problem for a while. I have also flushed the fuel system and tried it from a fresh 5 gallon portable tank to eliminate contaminated fuel as a problem, even though the other motor pulls from the same fuel source.

thank you

It sounds like a lot was done, but you still did not say if you did what Chris recommended.

That is basic, like going to the Doctors and getting your blood pressure, temperature and weight checked.

Also...you did not say if you switch ECM's. If they just checked the resistances, that does not guarantee that all of the functions are working.

Mike

I was unsuccessful in locating an adaptor to connect my fuel pressure guage. Maybe I can borrow one from the Honda shop. The ECM's have not been swapped, just tested for resistance. My parts motor is a 1998, most parts are interchangible, but I was not sure if the ECM was compatible with the newer 2004 model. If so, I can swap them tomorrow and try it. My motors are 2001, 2004, and parts motor 1998.

Another piece of information I just remembered, and may not be related,is somewhere near the begening of this problem I started getting a sporatic alarm. It was an intermittent beeping and not continuous. It would come on randomly, like 8 hours into a trip for seemingly no reason and stay on as long as the motor was on. Then it would disappear and come back a week or so later. Swapped a number of sensors, but could never duplicate alarm at house to see if problem was fixed. Alarm hasn't came back for 2 years now, but i never felt 100% sure i found the cause.

Further progress on the motor. The top 2 plugs are wet, while the bottom 2 are dry. I cleaned and rechecked the injectors and all 4 are functioning and putting out equal amounts of fuel. I'm assuming the trouble is with the 2 wet plugs not burning the fuel off. However, I can visually see spark on all 4 plugs when removed from the motor. Is it possible that the spark is weak enough that once the plugs are in the pressurized cylinder that its not sparking enough to burn the fuel, then once the motor starts, with use of ether, it has enough spark to run properly?

My next step is to start swapping out plug wires and see if that solves anything. Right now it's 20 degrees with a 50 mile an hour wind so it may be a day before I get back to it. Any other suggestions?
thank you

Laying plugs on the block is a waste of time.---Make the spark jump a gap of 3/8" or more for a proper test.

How did you clean the injectors? Just because fuel is passing through them does not mean that the engine will run on it. Flow has to be checked along with spray pattern.

Maybe clean wasnt the proper term as you cannot reach the internals of the injectors. More less removed them, wiped off any gunk, which there was very little, and inspected for any visual damage, corrosion, or pluged jet. after reinstalling them I turned the motor over while watching the injectors. They each sprayed an identical looking pattern. Next, I put a clean cloth behind them and turned it over again. They each left an identical pattern and amount on the cloth. Earlier on in the hunt for this probem I swapped them with injectors from the other motor without change in condition, so this was basically backtracking trying to figure out why 2 plugs were wet and 2 were dry. I was trying to confirm they were all getting fuel, since I can see spark on all plugs, at least while removed. I can also pull each plug wire while it is running and hear the change.

To answer your question on the ECM compatibility...I do not know for sure.

If you were to order an ECM new for the 1998 engine, the part supercedes to the same part number as the one for the 2004. I can not see anything that indicates it will work the other way.

Also....how is the compression?
Do the timing marks line up?
Has anyone checked the valve clearances (especially intake valves)?
While checking valve clearances , has anyone checked to be sure the head bolts are torqued properly?
Has anyone checked the PCV valve? This and the 115 are the only Honda outboards with PCV valves. It is located mid engine, starboard side, just above the intake manifold.

For a fairly simple engine, there are a lot of things to check.

We have about the same temperature here, but certainly not the wind. I feel for you.

Mike

Not sure on the ECM, but I tried swapping them and it didn't make any difference so I put the original one back on. I don't believe anyone brought up the pcv valve before, I'll try that next. I have checked the timing marks and am not positive about their proper alignment, I don't have a manual for that motor. However, they match up exactly with the marks on the other motor, so I assume its aligned properly. Considering it fires right up when warm I would think its something else, but will definitely peruse all possibilities. I need to get this thing fixed.

To my knowledge the valves have not been checked, I am the second owner. Valves were mentioned by the honda mechanic as something to check, but in his opinion not the most likely cause.

Compression was good. I believe all were between 178 and 180. It was checked with the throttle wide open, but from a cold engine in 20 degree weather.

I'm sure head bolts have not been checked for torque.

thanks for the suggestions and your time. Keep the ideas coming and ill try to work through them all.

I checked the pcv valve and it is not plugged. I did however discover the thermostat was stuck open. I replaced it, but still no change in starting condition.

in regards to the 2 wet and 2 dry plugs. I may have jumped the gun on that assumption. It was just the last thing I found that night. It was probably due to draining the fuel system earlier. After cranking it a couple more times all plugs are equally wet.

I'm beginning to lean towards the valve adjustment, but was hoping to discover something else without opening it up. Just thinking out loud here, could one of the temperature sensors being off cause this condition? I replaced them early on in this hunt, but its possible one of the sensors I replaced it with could have been faulty off the part motor, although not likely. Am I correct that there are only 2 temp sensors on this motor? One on the intake side and one on the exhaust side?

Any other suggestions?
thank you

Yes...only two that I know of.

Mike

I have no experience with these motors at all but...

Generally ECMs of cars (where I have experience) are somewhat similar. I believe they do do a few things different mainly in timing, & the fact that a marine engine is fully loaded most of the time.

For a cylinder to fire it needs a mixture between about 10:1 & 18:1. You can make it it fire outside these mixture ratios but you need a much more powerful spark (I think the newer 2 stroke engines burn very lean and what allows this is much more powerful ignition systems which is why they may produce much more interference in radios).

In cold conditions the specification for the mixture is much more critical. The fuel droplets from the injectors are not as fine and don't mix as well with the air.

You really need to measure the fuel pressure at cranking, not necessarily while its running. Even while you crank it over without the engine starting will do as once it starts it runs OK so will not tell you anything extra.
Compare it to your normal engine under the same condition (remove the plug leads so it wont start).

I assume you have swapped batteries as the battery is under most stress during starting, and may allow as full spark. A slowly failing battery fits all the symptoms. It may not be the fact the engine is now hot, its the fact that the battery has had a quick top up of its charge from the running engine. The engine cooling down may be just the time the battery needs to discharge enough.

Also try checking the spark while the engine is cranking under load. Just use a separate known good spark plug and leave the motors spark plugs in place.

Again compare it to the known good engine under the same conditions. The color of the spark should be the same on both engines.

It may very well be a mixture problem. Rather its the valves or a sensor, or something else I don't know.

I don't believe it's a fuel issue as I have swapped both fuel pumps, fuel rail, and injectors with no change in performance. However, I have been unable to find an adaptor to connect my fuel pressure guage to get an exact reading. Visually, the injectors put out the same mist on both motors when cranking. I'd just splice into the line and replace it if I could, but it appears to be a "high pressure" hose with a solid core.

I compared spark colors between the 2 motors and they look identicle. Both motors run off the same batteries. Both are new, less than a year old anyway and the motors turn over very fast, even when cold.

One test to do is run the boat on one motor at a time and see if they both rev to the same point and push the boat to the same speed. (leave the other motor in for extra drag)

If they both perform close to the same its just a starting problem. If the hard starter engine doesn't get to the same revs, then its down on power it can be mixture (fuel pressure), valves or a sensor.

You can fully block off the PCV Valve without damage to test whether its faulty when its cold, but the ECM may detect the blockage and adjust the mixture once its running. At start up and idle the PCV valve should generally be closed

The PCV valve stuck open would usually cause the engine not to idle BUT the ECM may correct for this by adding more fuel.

In theory at least, the engine would be hard to start with a PCV valve stuck open (or a leaking PCV hose) but once going the ECM may be able to keep it running by enriching the mixture a bit. It would be like having an air leak in the inlet manifold. Perhaps test the manifold vacuum at cranking speed of both engines (disconnect the plugs). That may give you one more piece of the puzzle.

That's the trouble with ECMs, the symptoms they throw up may not necessarily point to the actual cause because they try and adjust things to keep the engine running. For instance an air leak in the inlet manifold may not effect the power of the engine as the feedback from the oxygen sensors just increases the fuel to compensate.
It may make it hard to start as the mixture is usually fixed (they usually have a separate mixture & timing lookup table just for starting) for starting and then changes to a different table depending on feed back from the O2 sensor/s

Its unlikely to be valve adjustment as that would more than likely show up in the compression test.

As I said before, I have no experience with these engines or ECMs though, so it just supposition. The gurus here might well comment on how the ECM detects how much air is coming in and maybe that would give you further clues.

They will use some sort of Mass Air Flow (MAF) or measure vacuum & temperature and do some calculations. The MAF is the more elegant way to do it these days, as it works for boost as well as vacuum, and measures the actual flow as apposed to the volume.

This motor has no O2 sensor or MAF's. It is a very basic fuel injection.

If your thermostat is stuck open, the motor has not been operating even close to operating temperature. It didn't have a chance, especially in the cold waters of Alaska.

The compression is a little on the low side, but at least fairly even. It should be 199 - 228 psi . The cold weather could be the cause. The valves may also be carboned up. It may have been running too rich, since the ECM should be telling it to use more fuel due to the cold. Although, it hasn't been doing too good a job doing it at start up.

And yes, I agree, the bad thermostat should have no direct affect on start up....but if running rich, the engine could build up carbon.

Once the thermostat is replaced, it might be worth the time to decarbonize. If you have access to a 3 gallon tank and a dealer that sells Yamaha Ring Free, make up a mixture and run the engine on that. Drain the existing fuel from the vapor separator before you do that, to save running time, getting the mixture into the injectors faster.

You can also use Sea Foam, but I have had much better and quicker results with Ring Free.

I like to run at a medium speed for about 15 minutes....turn off engine and let sit for a while.....then run the crap out of it for about 5 minutes then medium speed for 10 minutes or so....then shut the engine off again...and repeat two or three times. After about the third time, I like to recheck the compression to see if there is any change. Others or the local dealer may have other approaches.

The other way is just to use it in your fuel and allow it to work over time.

You should not need any more than the three gallons, if the procedure is going to help.

Then just let it sit until it is cold and see if it starts any better when cold.

Back to the temperature sensors. You can perform an ohms check. They are both the same sensor. There is a chart, which I can not copy but these are a few points from the chart.

@104deg F - Approx 1k ohm
@58 deg F - Approx 3k ohm
@32 deg F - Approx 6K ohm
@14 deg F - Approx 10k ohm
@-4 deg F - Approx 20k ohm

As you can tell it is not a linear chart...it is more logarithmic. It has more drastic resistance changes at cold temperatures. If you get readings even close to those numbers, they are probably ok.

You have not said if you have checked for codes by using a shorting plug on the red service connector. I doubt if you will see any codes, but you never know. If you have not, let me know if you have a two pin or a four pin red connector.

Mike

I think the thermostat was probably a recent development, as it ran in tune with the other motor last Saturday. I have even ran then independently and they ran the same speed at the same rpm, however it has been a while since I have done that.

i tested the air temp sensors and at 5 degrees this morning and they showed 15.23 ohm. Looking at the numbers you provided it sounds like they are working.

The pcv valve seems to be working correctly. It's allows passage freely one direction only.

im assuming my compression numbers were due to the cold temps. I checked the other motor at the same time and it had a greater spread in numbers, but the total between the 2 engines was only 5 psi different. I semi regularly run seafoam through them anyway, but will look for ring free.

The port (problem) motor does not have a pmg light, just the oil and temp light. I tried to switch them and check for codes, but apparently don't have the proper connection to do so. Next I tried using a test light and checking the wires I do have coming out of it, but could get no reading from them either.

if I'm doing it right you use a paper clip to cross the 2 connections on the red dummy plug? Since I couldn't get a reading on the control end I checked for a signal in the red plug, but don't show anything there either? Am I missing something? Is there a way to check for codes without the pmg light?

thanks again

Seafoam will damage the pre-filter on the fuel injector.

There are two connectors on the front of your engine, that connect to the wiring harness. A 14 pin connector and either a 3 pin or a 6 pin connector. You need to find that 3 or 6 pin connector. You then need to find the Red/Blue and the Yellow/Black leads in that connector. Connect your test light between them and you have a PGM/MIL light (check engine) light.

Before you short the red connector pins, you can test by turning the key to on. The test light should come on for about 2 seconds, then go out.

Turn the key back off and install the shorting tool (usually a paper clip). If, when you turn the key on, the light comes on and stays on, there are no codes. If it blinks, count the long and short blinks.

Mike

I found a 14 pin and a 4 pin connector? The 4 pin has yellow/blue, yellow/black, white/black, white/yellow.

I am not sure what connector you found. Are you looking at one on the engine harness?

On most of the 130's, there was not an extra wire group/connector on the wiring harness that goes to the helm. A separate three wire cable was used to provide the Pgm panel connections.

Later, Honda made wiring harnesses from the engine to the helm that had the wiring included.

Unfortunately, the wiring diagram, even in the shop manual, is not very easy to read.

If you do not have a wiring diagram, you can find one on one of the last pages of the owner's manual. http://marine.honda.com/owners/manuals/models/BF130 Pick the one that refers to your motor by serial number.

I will keep looking to see if this has an explanation.

Mike

If your serial number is in the range of the one on the bottom....it does not have a wiring diagram in it. Pick the one above it.