Honda BF75 and BF100

[reelfishin]

I picked up a baker's dozen of these motors the other day, they were leftover from a rental or guide service that shut down years ago. All are mid 80's era motors, a few run, none pump water, two are siezed, and two won't shift and have missing parts. Two of the BF75 motors look new but are stripped of many parts, one has a gutted lower unit, the other is missing most of it's engine bolts and fasteners but is otherwise complete. My take is that they were parting out two new motors over the years to keep the rest running. I sort of figured the impellers rotted away with age, from sitting so long. In the lot are three 3.3 Gallon gas tanks, but no fuel lines, there are two styles of fuel couplers on the motors, one resembles a two pin OMC or Mercury style fitting, the other looks like an old Force or Chrysler fitting.

One big question, What is the difference between the BF75 and BF100 motors? I can see or measure no differences in bore or stroke, and other than decals, they are identical.
Is it a matter of carburetors and exhaust or is the 75 just a restricted 100? Out of this lot, I'd like to get the three BF100s up and running and maybe one BF75. None of these look abused, the two that are seized are super clean, they just won' turn. The one will turn a bit but it tight, the other is locked up tight.

I am not at all familiar with Honda, I have a manual on disc that came with these, but no parts list that I can see so far. There is no local dealer and the nearest Honda anything is a hour away. There is also two remote control kits in this lot, and some spare parts so it may be just a matter of some know how and time to get a few up and running. I'm thinking about a twin BF100 set up on a 16' tinny?

 

[hondon]

Re: Honda BF75 and BF100

Provided that these are all cdi engines,all parts are interchangable.There are differences in jettting between the 7,5 and 100 but other than that they are identical.Had a similar pile years ago and created three live engines out of eight dead ones.Fun project and not very hard.

 

[reelfishin]

Re: Honda BF75 and BF100

Thanks, I was sort of thinking it had to be pretty simple, I was comparing parts lists and every thing looked the same.
Is it a matter of just rejetting the 7.5 carb to make it a 10hp? Or do I need to use a 10 hp carb?

The one motor that would turn but not all the way turned out to be the timing belt, I put it on correctly and all is well. the stuck motor seems to be stuck down low as I have some movement up top but none at the prop.

The biggest drawback I have here is that there's no local dealer, the closest is about 2 hours north of me. There are a few package dealers but they don't stock parts and won't order older parts since they don't have parts books for them. (Pretty much they just can't be bothered). I went to one of the more local dealers in hopes of finding a new fuel hose to fit the original tanks, but was told that I'd have to spend $550 to convert to a modern tank, line and motor fittings. I went over to the Evinrude dealer, bought a fuel connector fitting and converter the one motor to fit my OMC tanks, problem solved for $6. I would just prefer these use their own tanks since these are the only 4 stroke motors I own, all other run on premix fuel.

 

[nowback]

Re: Honda BF75 and BF100

I found out a little on these motors and its not the carb that is the difference between the 7.5 and the 10
its the cam. i just got the 10hp cam to put in my 7.5
I was told thats the only difference.

 

[Chugger17]

Re: Honda BF75 and BF100

I am looking for a cdi unit for my honda bf100, part# 30580 881 733 or 732. Do you have one

 

[wal92tt]

Re: Honda BF75 and BF100

I picked up a baker's dozen of these motors the other day, they were leftover from a rental or guide service that shut down years ago. All are mid 80's era motors, a few run, none pump water, two are siezed, and two won't shift and have missing parts. Two of the BF75 motors look new but are stripped of many parts, one has a gutted lower unit, the other is missing most of it's engine bolts and fasteners but is otherwise complete. My take is that they were parting out two new motors over the years to keep the rest running. I sort of figured the impellers rotted away with age, from sitting so long. In the lot are three 3.3 Gallon gas tanks, but no fuel lines, there are two styles of fuel couplers on the motors, one resembles a two pin OMC or Mercury style fitting, the other looks like an old Force or Chrysler fitting.

One big question, What is the difference between the BF75 and BF100 motors? I can see or measure no differences in bore or stroke, and other than decals, they are identical.
Is it a matter of carburetors and exhaust or is the 75 just a restricted 100? Out of this lot, I'd like to get the three BF100s up and running and maybe one BF75. None of these look abused, the two that are seized are super clean, they just won' turn. The one will turn a bit but it tight, the other is locked up tight.

I am not at all familiar with Honda, I have a manual on disc that came with these, but no parts list that I can see so far. There is no local dealer and the nearest Honda anything is a hour away. There is also two remote control kits in this lot, and some spare parts so it may be just a matter of some know how and time to get a few up and running. I'm thinking about a twin BF100 set up on a 16' tinny?

To Reelfishin and Hondon, do either of you have parts that you're willing to sell for the bf100? Specifically the "adjusting Rod 50340-921-000 or the engine kill switch on the throttle handle? I dropped my adjusting rod in the river and my engine's kill/off switch is broken. I have to use the choke to shut off the engine. Please email me at WAL92TT@verizon.net. Also, do you know of any way to add more power to these engines?