BF30A Won't Start

Hey guys, you've saved me with this engine in the past (BF30A LHSA pre-1997), and I'm hoping you brilliant people will do it again, cause I'm all out of ideas. Let me give you the run down.

I would say this engine started having suspicious problems about a week ago, 2 trips before the engine totally died to be exact.

Trip 2 before failure:

The engine was running perfectly normal, however at idle it was having trouble staying alive. This is not new to me with this engine, sometimes I get a fuel lock and sometimes the idle control screw gets loosened. I dismissed this as normal behavior.

Trip of failure:

The engine was bogging down a little at the beginning of the trip. Again, I thought it was a fuel issue and after about 10 minutes, the engine was running normally. I turned the engine off as I usually do (this was a night fishing trip; I set a sea anchor and drift for about 10 hours). When I went to start it again to go in, the engine revved briefly for about half a second then cut out and died. I tried for about 10 minutes to start it (this is a pull start motor by the way). Long story short, I had to get towed in.

So now I'm dry docked and ran some tests on it.

Compression is good, over 100 psi in each cylinder which is the same as it has always been, and no leaks.

I checked the fuel lines for water or a fuel lock, cleared them all with compressed air, and they all looked good. I drained all the bulbs of the carburetors and didn't find any water. My bulb is priming.

I checked spark and every spark plug was good.

A few things to consider to diagnose this issue: I thought I smelled a slight burning smell at the time the engine cut out after revving up. I barely caught a whiff so I'm not sure what it was from. Also, I was messing with the regulator rectifier about a week ago and accidentally sent some current into the engine (don't judge I am terrible with electrical stuff). Since everything an engine needs to start checked out (compression, fuel and air, spark), I am wondering if something threw the timing off or I burned out an electrical component. I checked the main fuse and it is intact, but there may be other fuses that I am not aware of. Other than that I am thinking maybe carb related?

Any help is greatly appreciated, thank you all for your time.

Hi,

You might want to spritz carb spray (please don't use ether!) into the intake to see if it will fire off.

You are correct that it needs compression but 100 psi is below "marginal" for a Honda outboard in my opinion. At that compression it's surprising it wanted to start and run at all.

The lower the compression pressure, the less chance there is of vaporizing the fuel effectively for proper combustion.

Maybe it's how you performed the test.

Did you?:
Disable the ignition?
Empty the fuel system?
Remove all spark plugs?
Prop or hold throttle wide open?
Pull engine over at least several times per cylinder?

If you didn't check it that way, try it again and post the results. If you did the test properly there's always the possibility that your compression gauge is faulty. Using shop air to check it's accuracy every so often is a good practice. Compression gauges seem to be prone to failure in my experience.

Good luck.

Thanks for the reply, jgmo. I did everything you mentioned with regards to the compression test except for completely emptying the fuel system. I'll try it again with the fuel system empty and let you know the results. I also thought that for a recoil starter engine, a little over 100 psi is normal (especially for an engine this old)? Let me know if I am wrong on this. I am pretty sure it isn't a compression issue though because I've tested this engine with the same compression gauge several times and it has always given me similar readings. It still reads the same as it always has, and it has always run perfectly even with the gauge reading a little over 100 psi across all cylinders.

I'll try your idea spraying carb spray into the intake and let you know the results.

Out of curiosity, do you think there is any way that something could have somehow messed the timing up a bit? Or could this be an issue with the coils/CDI?

I see pontoon boat motors running fine on 100psi frequently. Generally it's because the owners have removed the thermostats. That means the engine will rarely if ever come up to the temp it's supposed to run at, and over an extended period of time, especially when run on mostly idle, the rings totally clog with carbon build up. The cure is to is to service the engine, install a new t-stat, and go run the hell out of it. Given the time, they will generally come back up nicely.

Something like a 30 horse that's hand cranked, do they have some sort of compression release to make starting easier?

If the plugs are firing, I'll be surprised if it doesn't try to start when primed. I use ether, but I'm darned careful with it, using just a tiny squirt.

Is the choke closing completely? If not, that might make something like this a real bugger to start....

As to could it have jumped time or is there a CDI problem, I guess anything is possible. But I wouldn't assume that.

I take it you don't have a shop manual? I had one but can't locate it since my kids rearranged my life when I got hospitalized.

You're probably going to need a manual or very detailed directions from someone that does if you want to check the timing.

I doubt that the CDI is the culprit since you say it has spark. Although if the spark is "weak" for some reason that would keep it from firing.

Alan makes a good point about the choke and, if that's the problem, the carb spray should have it at least trying to run.

Let's see what happens with that.

Good luck.

Alan, I am not sure about a compression release to make starting easier.

Jgmo, I have replaced the timing belt once before and do have a shop manual, so redoing the timing shouldn't be a problem if it does come to that.

I tried spraying carb spray into the intake and had no luck. So I took the intake manifold off and opened the throttle and sprayed carb spray directly through the carbs. The engine did begin running for a brief moment but stopped within like half a second. After that I had no luck. With the intake manifold off I also inspected the choke and throttle plates. Everything is working as it should and the choke is closing completely. I can even see fuel getting pulled into the carb by the diaphragm when I push the throttle open.

What do you guys think? It did barely start for a second, which is slightly promising to me. But it only happened once and wouldn't do it again. Still scratching my head on this one.

I'm confused. You took the intake manifold off??

Or do you mean that you took the muffler off?

If it was firing then that's a good sign the ignition is working although checking coil resistance might be something to look at.

Maybe it would be a good idea to check the valve timing since you have the manual and know how to do it.

I'm also curious about how this one does ignition timing (pulsar coil?) but I can't find the manual. Maybe you can look that up and check it too.

Have you ever checked valve clearances?

Can you elaborate on how you "sent current through the engine" when you were messing with the regulator?

Sorry, more questions and no answers.

Hopefully Alan has some better thoughts.

Sorry jgmo, I meant I took the muffler off; don't know how I got that mixed up haha. I'm not sure how to check coil resistance but I'm wondering about that as well; I'll look more into it. I'm definitely leaning towards timing, so I'll double check that the cam and crank pulleys are in alignment. As far as valve clearance, I adjusted that a little over a year ago and made sure it was perfect. I have feeler gauges so I can double check that as well. But would misaligned valve clearances really cause no start at all?

Not sure exactly how ignition timing works, but there is a cam sensor that sends a signal to the CDI, then to the coils, then the spark plugs. Electricity is generated via an exciter coil inside the flywheel, transformed and stored in a capacitor in the CDI. Do you think the cam sensor could have gone bad? Maybe exciter coil?

With the regulator, I didn't have a multimeter on hand to test the charging coil, so instead I just rigged up two wires with alligator clips on each side and attached them from the battery to the appropriate charging wires to see if there was a voltage increase on my battery (I have a little voltmeter for the battery on my boat). They slipped off and touched the block for a bit, I saw the voltage on the battery drop and some sparks from the clips onto the block. Stupid I know. I don't know if that could have caused any problem. I stopped and started the engine just fine after that.

I appreciate all your and Alan's ideas. I know we have to ask a million questions before we find the right answer.

Sam I've found the Honda ignitions pretty much rock solid. That's the last place I would go regarding an engine with spark not starting.

Well....

Last point first....the "sparks" method of electrical testing. If it' was still running and charging the battery immediately afterward, I doubt that you damaged anything. You would need a multimeter to do any meaningful testing if you wanted to look at the ignition coil values though. Your mistake has already shown you the consternation of not knowing "what the heck just happened?" A multimeter is a DIYer "must have" in my opinion.

I have seen some valve adjuster jam nuts back off before and that usually results in a valve not opening so I wouldn't completely dismiss that as a possibility. Would it keep the engine from trying to start? Probably not but....

Yes, the "cam coil" or pulsar mount can get loose or have connectivity problems and upset ignition timing. It's also a place where moisture and dirt finds a place to settle into and cause problems. Unlike Alan, I've seen plenty of Honda ignition problems on the twin engines I typically work on. Don't assume anything.

But, in this case, it still seems more likely a fuel delivery or possible valve timing issue from my many miles away location.

I still don't like your compression pressure. Did you retest?
Have you ever heard of a "wet" compression test? Not as easy to do on a horizontal piston engine but would give you some good info about piston ring condition.

Jgmo, I'll do another dry compression test and then try a wet test. But like I said, it's always had the same psi I'm getting, and it's always run perfectly fine at just over 100 psi. Will it be ok to put oil in the cylinders that I may potentially have to leave there for some time? If I can't get this engine started in the next couple of weeks its gonna be sitting for a few months.

I've got a lot to check on, so I'll run a few tests and look at timing, clearances, and the cam sensor and get back to you guys if I have any success/new findings. Thanks to both you and Alan for all the help so far.

Check your engine specifications for what the compression was new. I think it was north of 185-190 psi. If I'm correct, it's lost approaching 50%..

I'm not arguing with "they run with 100 psi compression". I know that they do. Plenty of the old twins I work on run on low compression. Do they run "fine"? Some think so but not me. Adequate?....maybe. The point I'm trying to make is that, at half it's designed compression, the engine is sort of at the edge of the run/won't run cliff if you get what I'm saying. It's kinda like the brakes on your car. Will they stop you at 50% efficiency? Sure! But how 'bout the next time?

Please! Don't let me talk you into doing something that you think isn't worthwhile. It's just MY opinion and I'm just making suggestions.

To do a wet compression test you MUST get the oil to spread across the top of the piston. On an outboard this means that you have to tilt it up drastically to get the crowns level with the ground. Just squirting oil in the cylinder isn't worth your time and won't give reliable information.

If you have a trim/tilt unit, that makes it very hard to do unless you disconnect it. I assume it doesn't have one because it's a pull start. If it has a trim unit it would be much easier to acquire a leak down tester and test it that way.

To answer about the oil staying in there, you will be pumping it out when you remove the compression gauge and move to the next cylinder. On the last cylinder you simply remove the compression gauge and pull the engine over a couple of times before reinstalling the spark plugs.

Jgmo, I took your advice and reperformed the dry compression test and also did a wet compression test. Also, I finally found the compression specs for my engine, it says it should be 198-226 psi @ 500 rpms. Mine is definitely not even close to that, but then again I'm definitely not cranking it at 500 rpms, so I don't know. Someone on this post: http://www.marineengine.com/boat-forum/showthread.php?410397-honda-30-hp-low-compression mentioned that compression on a BF30A for a recoil starter is about half that of an electric start. Not sure if he is correct in any way.

Anyway, the results of the compression test were interesting. For the dry test, I was able to get every cylinder to exactly 110 psi. After performing the wet compression test, I was able to get every cylinder to exactly 150 psi. Right after the wet test, I decided to put the spark plugs back in and spray a little starter spray into the intake, and to my surprise, the engine actually started for a couple seconds. It didn't rev, just putted for a couple seconds and cut out. Let me know what you guys think of these results.

Other things to note: timing marks are perfect and valves look good.

I think I'll perform a leak down test to confirm if I am losing compression. I'll let you guys know the results.

Well, the real good news is that you say that the compression is 150 on all three cylinders. And, 110 is much better than 100psi for the dry test.


This makes me think that your engine is much healthier than I had been thinking it might be.

Adding the oil emphasizes the reason for disabling and draining the fuel system before testing.
Any gasoline entering the cylinder will wash the oil off of the cylinder walls and skew the results.

The pressure increase with the wet test shows that there is a loss of sealing at the rings. But with the cylinders all being equal like that it could very well be just as Alan said previously about carbon buildup interfering with the ring's movement in the lands.

Having it fire on starting fluid again shows that the ignition is alive so it's looking like a fuel delivery problem. This is the point where I would be trying to start and run it on propane to confirm that.

Thinking if it's running on a prime, it's about fuel. Or refined one step further, why isn't it getting any?

Are the fuel filters and float bowls full of water, 100% fuel conditioner, or something other than reasonably fresh gasoline?

Maybe drain the float bowls to see if something/what comes out?

I suppose, if the spark plugs are old, they may have fouled to the point they're causing the hard start.

Well thats some slightly reassuring news. I'll go get some brand new spark plugs and see if that does anything.

Jgmo, how would I go about clearing any possible carbon buildup without having the engine able to start? And I've never heard of running an outboard off propane, how is this done?

Alan, I checked the fuel filter, fuel water separator, and float bowls, and cleared them all. Didn't find any water or other debris. The fuel I am using is only about a week old. When it died I was running it on fresh fuel. Also, do you think it counts it as "running" on a prime? It barely started and couldn't even stay putting for more than a couple seconds.

Any thoughts on exhaust issues causing a problem like this?

Thanks to both of you for trying to help me, I appreciate the feedback so much.

I think maybe a lot of this issue is the difficulty hand starting a 30hp 4 stroke. I can't even imagine..... Not something you would ever find in my stable for sure.

This motor is going to need to be right if it's going to start reliably. As in EVERYTHING right!

A couple of "putts" is about all you're going to get pulling it through by hand. If it doesn't take off on it's own from one of those firing stokes (likely WAY more powerful than pulling it through by hand), you're going to have a bad day (and a sore shoulder).

Do you have the throttle cracked open a hair on these start attempts? Not a lot, but not closed either. If the throttle isn't "cracked" any of these outboards can crank quite a while before running on their own.

I don't know if the exhaust is subject to getting blocked on one of these. Most Hondas are thru prop exhaust and I think it would be hard to even intentionally block it so that it wouldn't run. But I have heard about cases of hard starting with outboards mounted too deep in the water setting up excess exhaust restriction. So, like I always say, anything is possible.

You say you have "good spark" and the timing is right. Well, running it on propane can prove that spark is adequate.

Propane gas is very close to the "stoiciometric" of gasoline. A fancy way to describe the air/fuel
ratio needed for running an engine. That's why they use it and natural gas as alternative fuels.

Propane is already in gaseous form so it doesn't need to be atomized in a carburetor or fuel injector for it to readily mix with oxygen. It's ready to go right out of the bottle! I've run many engines, carbureted AND fuel injected, with nothing more than a plumber's propane soldering torch rig. A screw on bottle soldering kit will supply enough gas to run a V8 car engine and allow for throttle response control.

On an outboard, you need to leave the muffler ductwork intact because you want to introduce the gas directly into the air intake. In some cases you can just blast the gas right into the air opening. On the twins I remove the torch tip and attach a hose on the end of the torch pipe to "snake" it up into the muffler. But they only have one carb and you have three. So don't feed the intake in such a way as to only feed one carb.

On a pull start as big as yours you will need a helper to pull the engine over while you feed the gas into the intake and operate the throttle.

Of course the gasoline must be disconnected and drained.

The choke must be left OPEN and the throttle cracked just a hair so that enough fuel can enter the engine. If you leave the throttle plate completely closed or close the choke, it won't work because the engine can't "breathe in" fuel.

If you crank it with the throttle wide open and it starts, the engine will overspeed so don't do that.

Make sure your crankcase vent system is clear and open to prevent gas from accumulating in there. That's about the only hazard that there is with doing this.

It's best to do this outside for obvious reasons but I've done it in my well ventilated barn/shop no problem.

This is a tried and true troubleshooting technique used in thousands of repair shops every day to prove/disprove fuel delivery problems.

It is safer than squirting liquid ANYTHING into an engine for both the engine and YOU. Just basic, simple precautions are needed. like having a fire extinguisher close and not allowing the propane to "pool" in an enclosed space.

Run the engine this way only long enough to verify results even though it is fun to throttle the engine on propane because of the novelty of the experience. But keep in mind that you are NOT precisely metering fuel here. You're just trying to prove a point.

If you decide to try it, I commend you because it will definitely expand your troubleshooting skills and experience.

Good luck.

Forgot to mention that, if it won't fire and run on propane, that spark you have is probably too weak and is the reason that you're having trouble.

Alan, yes I always start it with the throttle about 1/3 open.

Jgmo, thanks for the detailed procedure! I'm definitely going to give it a try. Will post results. Out of curiousity, can you use butane as well as propane?

I have never tried using butane so I'm not sure if it would work or not.
I only recommend using the propane for doing this.

Good luck.

Thought I'd let you guys know the good news, I got it going! Turned out to be a fuel problem like you thought. Actually had nothing to do with the carbs, just bad gas. That or spark plugs. I drained the fuel system a second time and put new e free into it. Also changed the spark plugs and put some dielectric grease on the plugs. Started second pull. I'm feeling pretty stupid right now, not gonna lie, sorry for pretty much wasting your guys' time haha. Either way, thank you so much jgmo and Alan for your input. Till next time (hopefully there isn't one).

Awesome! Love those happy endings....

Thanks for getting back with us.

The reason I had mentioned making sure what was in the fuel system is actually (reasonably fresh) gas was a friend brought me a motor one day, with similar story. Turns out he had put a gallon (!!!) of Stabil in the otherwise empty fuel tank. Forgot to tell me about that when he dropped it off. To make a long story shorter, Stabil by itself will NOT fire. It might just as well be water.....

Well....I don't agree that any time was wasted. Most of us are here to learn and I really like the "intrigue" of seeing someone solve their mysteries. It's the GEEK in me I guess. No need for apologies here.

Too bad you didn't get to running it on propane. It would probably have fired up on the FIRST pull and another "convert" would have been made in the troubleshooting world.

But... I guess that stuff isn't really for the guy that just wants to get it over with and get back on the water;>)

Glad you got it sorted out.