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Honda BF30 Oil Leak - Any ideas or suggestions?

SinkTip123

New member
Here are some pics of my 1996 (or so) Honda BF30 Longshaft.
I was doing some work on the lower unit (thanks everyone who helped) when I noticed an oil leak coming from between the lower engine case and the leg extension case (I got these names from an online parts manual).
I have never had one of these apart yet so I am without a clue as to what would be leaking oil to have it seep out there.
Here is a couple of pics showing the outboard and the leak.
One thing I just thought of is that the outboard is mounted on a CMC tilt trim unit and possibly it tilts farther than factory causing oil to drip from the filler or dipstick tube? Just a thought - it should be so easy...
Grant Brown
White Rock, BC

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I like to start high and work my way down the engine.

I see you took a picture of the under case around the powerhead. Do you see any oil in that area? If so, it may just be seeping down through some of the drain holes in the under case.

Again...if oil is seen around the engine...could it be coming from a loose oil filter (should be tightened not just hand tight) or could it be residual oil from the mess that is generally made when changing the oil filter?

If you have had the valve cover off, check around there are leaks. Another spot is the oil pressure switch.

If there are no visible leaks up top, then the only next step is to remove the lower unit, then the extension case, working your way up to the oil pan to see if the leak is coming form there.

I am sure Jimmy has a technique for finding oil leaks. I think there is some sort of additive that you can put in the oil that is visible with ultraviolet or similar light to help trace to the source of the leak.

I normally takes a lot of patience to find the source.

Mike
 
Thanks Mike,
I saw a little oil in the under case but it didn't look like enough to cause that much of a leak. I will check the things you mention and dig a little deeper this weekend. The experienced help and suggestions are very much appreciated.
Grant
 
That looks like really FRESH engine oil. One thing that happens to me is that I always pre-soak my filters before install. And, even though I use a little "skirt" to catch and direct the spillage away from the engine and case, it still gets messy sometimes. If there was some spillage during a recent service, the oil could have pooled up and then come out of "hiding" when that OMC tilt was maxed out.

No secrets for finding oil leaks here. And, even though I do have one of those ultra violet leak detection dye kits, I rarely use it. As Mike says....let GRAVITY be your guide...and friend. You always have to go to the highest point of travel to find the source.

Good luck.
 
Here is another thought...from left field.....

Could that discoloration be caused by fuel? You did say the the CMC tilt mechanism may be tilting up farther than what is normal for the motor. Maybe it is fuel coming from the carburetors when it is tilted way up and working its way down through the various drain holes....picking up some oil residue along the way.

Told you it was in left field....

Mike
 
It looks like the middle carb float bowl is leaking. You can see in the pic that it is wet and there is actually a drip of fuel from one of the screws. I'm thinking that this is beyond my abilities unless its a really easy fix.
Is there danger in running it like this? I wanted to get out next weekend but don't want to take a chance at running it lean and burning it up.
I'm glad it's not an oil leak but any thoughts or suggestions?
Grant
 

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Make sure it ISN'T as Mike suggested. That tilting the outboard may be causing fuel to exit a vent. There are several vents in these carburetors.

When seeking the source of ANY liquid leak, always look ABOVE where the liquid is visible and see if you can discern a "trail" coming from someplace else. I would use a small dental mirror and a good flashlight to eliminate all other possible leak points before coming to a final conclusion. In my youth I had to "live" this lesson a few times when learning to work on 18 wheelers.

Is it an easy job to re-seal the float bowl? That is relative. I would say YES, others might say NO. It just depends on how mechanically inclined you are with disassembling things and then reassembling them. Because, that's basically what you are looking at, IF it is the float chamber seal. Fairly straightforward as my old boss used to say.

But, it doesn't sound to me as you you are very confident about working on your outboard so, you may need some help.

If you do decide to give it a try, I'm pretty sure it is easier to take ALL the carbs off together to get to the middle one. So, you would need to do some prior planning before you start. I would suggest sealing all the carbs if they are off as preventive maintenance (one leaked so the others will too) so you will need three float chamber seals and three mounting gaskets at the very least.

If you don't own the HELM INC. official shop manual for your outboard, this would be an EXCELLENT excuse for getting one. It will make you MUCH more prepared and will probably increase your confidence in your ability for doing the job. That manual is a great INVESTMENT whether you do the work or hire someone. It will give you the information you need to make sure the job was done right. A Helm manual will pay dividends for "clearing things up" over the entire time you own the outboard.

I would certainly NOT be comfortable taking any boat out that had a fuel leak. Murphy's Law dictates that, not knowing EXACTLY when the leak will SUDDENLY get MUCH MORE SEVERE, it will probably happen with the engine at full throttle with your attention on steering and your back to the "problem" until the flames are REALLY high.

I was once trapped in a boat cabin by a fire from an alcohol stove between me and freedom. "No problem" I thought..."I'll just grab this here fire extinguisher, pull the pin and squeeze the trig......er...UH! WHOA!>>>>>
NUTHIN'!....YIKES!..... WE'RE ALL GONNA DIE!!!!!

Luckily, my buddy kept HIS cool, knowing that alcohol fires can be put out with water, he grabbed a big bottle of Aquafina and had the fire suppressed in a jiffy.

So, if you're thinking about taking an extinguisher with you and "chancing it" remember: gasoline CANNOT be safely put out with water and fire extinguishers don't always work.
 
I don't want to sound like a Honda manual salesman but if you're interested in cleaning your carbs while they are off, the Honda Carburetor Manual is the "bible" for going in and doing it right. Even if you've never worked on a carb before, that book clearly explains all the "mysteries" of operation, cleaning, and syncing your carbs. Invaluable for DIY and will keep you out of the "clutches" of HACK mechanics who can cost you a lot of money while making your life miserable when they blow the tune on your outboard.
And, if you gulped with sticker shock when you priced the Helm shop manual, the carb manual is not nearly as expensive. With those two items in your posession, some basic tools, a digital camera and notebook you can save THOUSANDS doing your own wrenching.
Like the Snap On tool dealer told me years ago....
Quality isn't expensive......it's priceless!
And that is true when it comes to those two publications.
 
Just wanted to add that you need to make sure to carefully match the Helm manual for your outboard to your frame number as there may be more than one choice for the 30hp outboards.
The carb manual is universal coverage so there is only the one. Both should be available through Amazon but if you have trouble finding them, I or someone else here can help. Just ask.
 
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