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BF75 and BF 100 carburetors interchangeable?

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23sailor

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I need to replace my Honda BF 75, which I use for the auxiliary for my 23 foot sailboat. I recently replaced the carburetor on the BF75. If I find a suitable BF100, will my new BF75 carburetor be compatible on the BF 100? I don't need the "extra horsepower" of the BF 100; the BF 75 is perfectly adequate. Thanks for any experience here.
 
Well...

It's going to depend on how close the manufacturing dates are between the two outboards. The pre 97 75 and 100 Air Guide carbs are actually the same but there was a change in the later years of the 7.5 to a different carb manufacturer.

Item 8 in the link below is for a 7.5

https://www.boats.net/catalog/honda.../7-5hp/bf75c-la-pre-1997/carburetor-air-guide

See item 7 in the link below for the 10 hp.

https://www.boats.net/catalog/honda.../10hp/bf100z-la-pre-1997/carburetor-air-guide

My question is where did you get a replacement carb since they aren't available from Honda any longer. If you bought a used one it may have come off of a B100.

Anyway,
Good luck.
 
Wow! What a wealth of information! A few years ago, I bought a new carb for my 7.5 online for about $170. It saw very little use, with life getting in the way. We found some time to use the boat finally, but recently had issues with salt build-up in the motor, and even with cleaning the manifold area, changing the thermostat, and flushing with vinegar, I have not come to trust the 7.5 again, but I was wondering if keeping the newer carb in service on a 10hp motor would be a wise move. I do not need greater horsepower. You are correct that the carbs are no longer available. If the need arises, I hope I can get rebuild parts.
As far as purging the rest of the engine interior of salt deposits, do you have any ideas there? I could clean the manifold area and replaced the thermostat, but how do you reach the deeper interior channels within the block? I haven't given up on the 7.5; I just don't fully trust it. Any ideas will be greatly appreciated. Best to you, Glen Moore, Seattle.
 
Well, other than getting what you can at the intake manifold, you could take the cylinder head off and expose the block water jackets. You can physically scrape, pick and wire brush at deposits that way. A Dremel tool with various wire brush attachments can be helpful doing some of that.

But the minerals from salt water tend to "meld" or bond with the metals and getting a badly plugged engine cleaned out is next to impossible sometimes without removing too much cast material.

Salt Away and vinegar are kind of the old standby flush agents but I don't have a lot of experience using either one. If these were closed cooling systems then some of the automotive system flush products might work. But using them in a trashcan without overheating the engine might be difficult. It could be expensive also to treat that much water.

I use CLR a lot for descaling things in my home where the well water can really cake things up fast. I have often thought about using it to descale outboards too but I've never gotten around to trying that either.

There have been posts on this forum from other members that have used products that I have never heard about and I remember some claiming good results. You might dig around in the archives for some of those.

Sorry, I don't have any silver bullet solutions for you.

Good luck.
 
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Thanks for the thoughts, jgmo. This is one of those time in life I'm reminded of the whining kid: " I KNOW everybody has to be SOMEWHERE mommy, but why do we have to be HERE? Won't give up on the old 7.5 just yet, and my quest will go on. Stay well, Gleno
 
After seeing you're in Seattle and your handle is 23sailor, thought I would mention that I have a San Juan 23....it was my first "real" sailboat. I should have let someone else have her by now but I'm a notorious pack-rat ;>)

Fair winds.
 
Wait a minute..... did I write about my problem to myself? I'm literally in the same boat, and to make it worse, I worked for Clark in many capacities back in the day., including project engineering and tooling, and racing their boats all over the country. Small world, same problems.

My next issue is figgering out a replacement charging plug for the 7,5/10HP models. I have a failure due to the corrosion in the plug connection. There is nothing magic about the goal; get electricity to get from motor to battery, but the wet salty environment is a killer for brass contacts. I have no brand loyalty here; just a problem to solve. If you hear anything, You'll probably find me at Fisheries Supply scratching my head and grilling Carl. Thanks again for being in teh brain trust. Glen Moore
 
Yeah, my buddy had a Honda on his Pacific Seacraft. I had a very cold blooded, hard starting NOISY Chrysler 6 hp. I wanted a Honda SO BAD after a day trip with that EZ starting, QUIET Honda 4 stroke! Couldn't afford it though.

But the San Juan was such a great little sailor and was so easy to single hand, I finally just took the dang NOISEMAKER off the transom and parked it in the aft berth. As you probably know the SJ 23 is pretty crew weight sensitive and ANY outboard on one side of the transom was a kind of aggravation to me

The Chrysler was then only to be seen if someone's scared girlfriend wanted to have the boat upright and headed quickly for home! A REAL PAIN to get on the bracket and started underway but NOTHING makes some people happy unless a smoking piece of machinery is pushing them along 2 or 3 knots SLOWER than they could have been sailing!

Well...it does seem that Honda charging plugs are, indeed, hard to come by. I did not know that.

But my solution would be to just substitute a standard, polarity keyed, two terminal, automotive connector like a Weather-Pak and fashion a "nest" for it where the old one was domiciled.

There's a good aftermarket source for those and when I find their link I'll post it up for you. But any hot rod supplier.like Summit Racing will likely have what you need to "retro-fit" that baby.
 
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