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Old Honda B75 Fuel Issues

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harlets_hothands

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Hi, I’ve got a 7.5 Honda from the 70’s that’s having some fuel issues. Initially, the motor was wandering and then quit entirely while I was out. I wasn’t able to start it at all for a few days. I took the fuel pump apart and cleaned it, and now the motor starts and runs fine while in gear, but it’s idling rough.

I’m wondering if I can get away with sea foam or if I need to rip the carb apart entirely to solve the problem. Any help is appreciated, thanks in advance.
 
www.selffixer.com

Honda BF75, BF100, BF8A Outboard Motor Shop Manual

This manual covers the service and repair procedures for the Honda BF75, BF100, and BF8A outboard motors. Incorporates 1, Z, Y, and X Supplements Manual P/N: 6188224E3 Third Edition 2014 This manual covers service information on the following Honda Outboard models: BF75: SA, LA BF100: SA, LA BF..
www.selffixer.com www.selffixer.com

If your frame serial number matches the link above this service manual should have all the information and specifications you’ll need.
 
William01 said:
www.selffixer.com

Honda BF75, BF100, BF8A Outboard Motor Shop Manual

This manual covers the service and repair procedures for the Honda BF75, BF100, and BF8A outboard motors. Incorporates 1, Z, Y, and X Supplements Manual P/N: 6188224E3 Third Edition 2014 This manual covers service information on the following Honda Outboard models: BF75: SA, LA BF100: SA, LA BF..
www.selffixer.com www.selffixer.com

If your frame serial number matches the link above this service manual should have all the information and specifications you’ll need.
Click to expand...
It’s actually B75 4005446 and I’ve been struggling to find a shop manual for it. If you know where to find one that would be immensely helpful!
 
Hi,

Does this one have ignition points or CDI ignition?

The thing that might worry me most about messing with one of these old carburetors would be getting them sealed back up properly without replacement gaskets. I'm not averse to fabricating gaskets but these little darlings have some unique and odd shapes.

I wouldn't at all rely on being able to reuse any seal or gasket on that carb and I think it would be folly to do so anyway on something this old even if you thought you could get away with it.

Referring to the link below, the float chamber cover seal has a molded oring type seal with a flat section on one side. That might be difficult to duplicate with an oring repair kit. Doable for sure but could be a bit of a challenge to get it correctly refitted.

But the one that would intimidate me the most is the gasket between the float chamber and the main body. It is a very odd shape in the center.

It might be easy but, depending on how precise you'd need to be, it might really give you fits.
And, you won't really know until you can look at it directly.

I would try to be as delicate as possible to remove it in one piece.


Then there's the question of "who's been here before ya" and what have they done?

While I completely agree with checking/adjusting the valve lash on this old girl, The FIRST thing I would do is check to see that the choke valve returns to the fully horizontal position and stays there.

These are some TOUGH old classics and I hope you can get her "smoothed out" without too much bother.

Good luck.
 
jgmo said:
Hi,

Does this one have ignition points or CDI ignition?

The thing that might worry me most about messing with one of these old carburetors would be getting them sealed back up properly without replacement gaskets. I'm not averse to fabricating gaskets but these little darlings have some unique and odd shapes.

I wouldn't at all rely on being able to reuse any seal or gasket on that carb and I think it would be folly to do so anyway on something this old even if you thought you could get away with it.

Referring to the link below, the float chamber cover seal has a molded oring type seal with a flat section on one side. That might be difficult to duplicate with an oring repair kit. Doable for sure but could be a bit of a challenge to get it correctly refitted.

But the one that would intimidate me the most is the gasket between the float chamber and the main body. It is a very odd shape in the center.

It might be easy but, depending on how precise you'd need to be, it might really give you fits.
And, you won't really know until you can look at it directly.

I would try to be as delicate as possible to remove it in one piece.


Then there's the question of "who's been here before ya" and what have they done?

While I completely agree with checking/adjusting the valve lash on this old girl, The FIRST thing I would do is check to see that the choke valve returns to the fully horizontal position and stays there.

These are some TOUGH old classics and I hope you can get her "smoothed out" without too much bother.

Good luck.
Click to expand...
I did end up taking the carb apart and noticed the odd gaskets for sure, but was able to finagle them back into position. It’s running fine now, maybe idling a bit lower than I’d like. I did overfill the oil at one point so I’m hoping it’s just burning that off and things will smooth out after that.

If not though, I’ll check the gaskets first! Thank you for all of the help!
 
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