What do these 2 rubber hoses go to?

hogluvr

Seaman
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Dec 1, 2013
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Just bought this motor, old Honda BF100, best date I could get on it is between ‘72-‘79. There are 2 fittings with hoses dangling off of them, can anyone tell me what these are for?
 

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Alumarine

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Feb 22, 2005
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Those were added on by someone.
Normally there's two 1/4" holes there.
Looks like they've been tapped for those brass fittings.
 

flashback

Captain
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Jun 28, 2002
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That's really weird I have no idea why someone would do that. Does your motor run.
 

hogluvr

Seaman
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Dec 1, 2013
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Not yet that’s why I was asking. Motor was serviced and looks practically new! Didn’t want oil or gear lube ir anything spewing out if I got it started, that’s why I asked
 

Alumarine

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Not yet that’s why I was asking. Motor was serviced and looks practically new! Didn’t want oil or gear lube ir anything spewing out if I got it started, that’s why I asked
Those holes are open to the elements so you should be ok.
If you run it in a tub make sure it's about 18" submerged.
I won't be running mine for quite awhile but now I'm curious and will check it out.
Let us know what happens!

Update, I found a video of mine running in a tub and it shows the odd spurt of water coming out of 1 or both of those holes.
I'm thinking exhaust bypass.
 

hogluvr

Seaman
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Dec 1, 2013
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Those holes are open to the elements so you should be ok.
If you run it in a tub make sure it's about 18" submerged.
I won't be running mine for quite awhile but now I'm curious and will check it out.
Let us know what happens!

Update, I found a video of mine running in a tub and it shows the odd spurt of water coming out of 1 or both of those holes.
I'm thinking exhaust bypass.

Good to know! I wonder why somebody would tap & thread and hang hoses from it?
 

flashback

Captain
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Jun 28, 2002
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He’s dead unfortunately
well that is unfortunate, I have had a couple of old bf 75s used on a sailboat, and I do think those are idle relief ports and a bit of water and exhaust will be coming from them. I still have no idea why someone would add the plumbing to them unless the motor was mounted in some kind of well rather than the transom and they wanted to expel the exhaust overboard. Ive seen some sailboats that are built like that .
 

Alumarine

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Feb 22, 2005
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I still have no idea why someone would add the plumbing to them unless the motor was mounted in some kind of well rather than the transom and they wanted to expel the exhaust overboard.
That would make sense.
 

km1125

Chief Petty Officer
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Aug 10, 2016
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503
No idea why someone would do that.

One of the other reasons for those holes is to let air IN. After the engine is run and gets hot, then shutdown it would draw water UP into the exhaust if those holes weren't there. They provide a "vacuum relief" so the exhaust can't suck water back up in that case.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,092
Maybe a Previous Owner needed an Extremely Stealthy Motor and the Idle Relief was giving him/her away...

I have seen many Motors butchered over the Years, and can count on less than One Hand, an actual Improvement over Stock.
 

hogluvr

Seaman
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Dec 1, 2013
Messages
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Thanks for the replies guys, fir some reason I’m not getting notified, probably a setting? I tried getting her started and it looks like I’m not getting any spark, any ideas where to start?
 

Alumarine

Captain
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Feb 22, 2005
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Spark on these motors is very hard to see.
I usually turn all the lights out in the garage or put a cover of some sort over the motor when testing for spark.

Is the ignition a points type or CDI?
If points, you might want to clean them.
I believe they're under a cover on the small pulley.
 

hogluvr

Seaman
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Dec 1, 2013
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It looks like it just has a regular coil to me, then again I’m anything but an expert on these things. I only see 2 larger covers, the one goes straight to the carb and the other has something bolted onto it that goes to the carb also, would it be either one of these?
 

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Alumarine

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Feb 22, 2005
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The CDI coil looks like that. I don't know what the points version would look like.
If there are points they would be under the grey pulley.
Check for spark in dark place first.
Both plugs fire at the same time.
 
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