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help plz..b100 9.9hp

J

jesus760

New member
hello i just was handed down a boat and the motor runs great i just notice when i went to flush her out after a day at the lake and i noticed oil starting to build up in the tub i had it in,now my question is when i lifted the motor out of the tub there was oil coming out of very bottom peehole what causes this to happen? thanks for ANY help!
 
Where is this bottom pee hole?

Is there any oil appearing anywhere else...under the engine cover?

What does the oil level look like? High? Low?

Check your crankcase vent hose to be sure that it is not plugged with critter nests...

Have to figure out where the oil is coming from before you start changing seals.

Mike
 
thanks for the help..im talking about the very bottom hole by the prop..i have water and oil mixing somewhere. i don't have any clogged hoses checked them all fairly new as well,i don't see any oil under the cover. so i ran the motor again and checked the oil before i did so ran it for 10 minutes and sure enough the oil level did drop a tad. so where would this oil be coming from? thanks again for any help!
 
Make sure that when you are checking the engine oil, that you let it sit for a few minutes after running so that the oil up in the valve train area has a chance to drain back to the crankcase. If you checked the oil level as soon as you shut the engine off, then it would be normal for it to be a tad low compared to before start up.

Sounds to me like you may have a prop-shaft seal leaking gear oil. You should remove the gear-case fill screw (plug) and check the gear oil level and quality. The gear-case check and drain screws both can be difficult to loosen without "boogering" them up. I use an impact driver to remove them without damaging them. These service screws also can be a source for a gear oil leak if the little Oring that is used to seal them is damaged or missing.
 
thanks i did do all that but it seems to be leaking the engine oil from somewhere,like u said i ran it for 5 mins lets it sit for 10 mins did this 4 times..started out with 650mil of oil by the 4 run i was down to 500? im sure that it has to be coming from the motor. and i drained and refilled the gear oil in the lower unit and it was fine so again where would this oil be coming from?..i have the engine on my boat ready to tear down. i purchased a seal that sits? on the inside of the case? where the oil is stored,also purchased the gasket that the motor and case go together. just don't want have to pull the motor if not necessary,if i do replace the seal and gasket is there a special way of putting the seal on? thanks again your help is a lot!
 
jesus 760,

Well, in that case I would agree with you about it being engine oil. I've never been inside a B 100 9.9 and I only have the manual for a BF 100 so I don't even know what the differences are between the two. So, instead of speculating, I'm going to defer to hondadude or one of the other guys that will probably help you pin it down. I'll be watching with interest though.

Sorry I couldn't be of more help but I know hondadude will get back to you as soon as he has a chance. He's funny that way. Always wanting to help people with their outboards.
 
jgmo,

thanks for the advice anything at this point is good,i will be patient and see what happens here in the next day or two before i decide to just rip into it.
hopefully this thread will be help to a lot of people.
 
Hi jesus760,
Well, I hope Mike, (hondadude) is ok. I KNOW that he's gonna get back to you as soon as he can. He may just be super busy at his shop. As he has already stated, that vent is the place to start checking. Have you got the service manual for that motor? It sounds as if you are pretty much mechanically oriented as you say you are willing to "go deep" and pull the power head.

Like I said, I'm not familiar with the 9.9, except for the newer models, so excuse me if I ask a couple of questions that don't apply to your engine.

Does yours have a replaceable oil filter?
Have you taken the hose that attaches to the oil fill body and goes up into the intake manifold off and made sure it is clear and not cracked or broken in some way? If that hose is plugged up, it will allow your crankcase pressure to rise and could push oil out the lower crank seal.

There may be a breather valve at the front of the engine that will have another hose going to the oil fill body. If yours has that, make sure that is not plugged with a wasp nest or something.

I hate to say it, but it sure SOUNDS like you have oil running down the main shaft since it's leaking way down low and that could be from the crank seal. So, that would either be because the seal failed or the breather is plugged and pressure is pushing the oil out past the seal which could mean the seal is toast anyway. But, I would try to eliminate any possibility of it being a leak up inside the oil case before pulling the power head. And, I would urge you to buy the shop manual if you intend to do that. At any rate, you do need to verify that the crankcase vent system is clear before replacing any seals because a plugged vent will just blow out the new one.

We feel you pain.
 
hello,
first of all i do not have a manual but like u said im pretty mechanically incline,im told when i pull the motor that there will be a oil filter if so i will replace if necessary.
i will be takeing all the hoses off and double checking them,ill wait till i hear more befor i pull the motor thanks again for the help!
 
Well jesus760, like I said, I really advocate you getting the shop manual. There are a couple of little things that you need to get right when doing a power head, and the manual is the best thing to help you understand what you're getting into. It's not all that expensive and once you have it, you have all the specs for troubleshooting and it takes all the mystery out of setting up the timing and such.

IT'S GOT PICTURES!!

Not great pictures but pictures. And that helps a lot.

If you do find a clogged hose or vent valve, it would be worth it to replace or clean the parts and then try it again to see if the problem persists. Hopefully we'll hear more from Mike on the subject soon.
 
I am with Jimmy...I would not do this without the shop manual. Actually, unless I found something obvious, I would not do it at all... since most customers do not want to pay $90/hr for several hours work for a motor this age with no guarantee that I will be able to get parts that may be needed along the way.

It does look like you will need to pull the powerhead...that will be the only way to see where the oil is coming from. Everything Jimmy said about crankshaft seal etc...I agree with.

Before you pull the powerhead, be sure to check the breather hoses #29, 30, and 31 http://www.boats.net/parts/search/Honda/Outboard%20Engine/0/BF100%20SA%20VIN%23%20BF100-1000001%20TO%20BF100-1020309/STARTER%20CASE%20%2B%20CAM%20PULLEY%20%2B%20POINTS/parts.html

Make sure the one way valve #3 is not stuck.

One other thing...there is no oil filter, but there is a screen. Not sure if it can just be cleaned.

Mike
 
hello guys!

sorry it took a few days to get back here,well unfortunately i did pull the motor and changed seals and gaskets so to find out that hondadude was absolutely right!! i had a clogged oil vent so it cause it to not breath and was spewing oil.i couldn't thank u guys enough here u guys rock once again thanks everyone for there help!!!
 
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