Honda BF40 lower unit gear case crack

S

swf

New member
Hi all,

I have a pair of Honda 40’s. They have roughly 400 and 250 hours respectively (Stbd motor used for salmon trolling, hence the difference). The boat is a 2002 and I think the motors are also. They start and run perfectly. I have been happily using the boat since our purchase earlier this Spring. However, while at anchor after a recent trip across the Strait of Georgia, I noticed that both motors have a crack in the lower unit gear case forward of the propeller. I have read on other forums that this may be a well known Honda problem perhaps related to corrosion emanating from a lower bearing retainer nut.

My questions are two fold. Do I need to have the lower units replaced by perhaps just buying a new gear case and swapping out the innards, or can this sort of crack be welded? Second and more pressing issue is, can I run the motors safely for now, or am I on the edge of ending up with two defunct engines 10 miles from land at any moment? I would really like not to have the boat out of service for the rest of the summer. Anyone else had this issue? I have no idea how the cracks developed but understand from Mr. Google that I am not alone.

Thanks
 
I am aware of repairs having been made for this problem. Be sure that the prop shaft/bearings are still aligned, after the heat of the welding. I would think that it would be safer to take the lower unit off the engine for welding--no chance of damage to the engine electronics/computer/charging output.

J B weld has been used as at least a temporary repair. In any case the crack has to be ground put properly.
 
swf":f1qxkakv said:
Hi all,

I have a pair of Honda 40’s. They have roughly 400 and 250 hours respectively (Stbd motor used for salmon trolling, hence the difference). The boat is a 2002 and I think the motors are also. They start and run perfectly. I have been happily using the boat since our purchase earlier this Spring. However, while at anchor after a recent trip across the Strait of Georgia, I noticed that both motors have a crack in the lower unit gear case forward of the propeller. I have read on other forums that this may be a well known Honda problem perhaps related to corrosion emanating from a lower bearing retainer nut.

My questions are two fold. Do I need to have the lower units replaced by perhaps just buying a new gear case and swapping out the innards, or can this sort of crack be welded? Second and more pressing issue is, can I run the motors safely for now, or am I on the edge of ending up with two defunct engines 10 miles from land at any moment? I would really like not to have the boat out of service for the rest of the summer. Anyone else had this issue? I have no idea how the cracks developed but understand from Mr. Google that I am not alone.

Thanks
Click to expand...


An aluminum casting is porous and laced with pockets of impurities & tough to weld when new. Add some salt corrosion
and a little gear oil, the labor to grind, clean & weld will possibly be a wash with the cost of a new housing. I just spent 2, 10 hr days tig welding a 6" crack in my Suzuki anti cav plate. (caused by some don driving SOB in the harbor) Good luck on your repair & let us know how it turns out.

:beer :beer
 
I agree with the posting above. Yes it can be done. Even still, I am a very proficient TIG welder and opted not to even try the repair when mine cracked years ago. While the lower units are expensive, they are not that expensive.
 
tsturm":3amihdvc said:
swf":3amihdvc said:
Hi all,

I have a pair of Honda 40’s. They have roughly 400 and 250 hours respectively (Stbd motor used for salmon trolling, hence the difference). The boat is a 2002 and I think the motors are also. They start and run perfectly. I have been happily using the boat since our purchase earlier this Spring. However, while at anchor after a recent trip across the Strait of Georgia, I noticed that both motors have a crack in the lower unit gear case forward of the propeller. I have read on other forums that this may be a well known Honda problem perhaps related to corrosion emanating from a lower bearing retainer nut.

My questions are two fold. Do I need to have the lower units replaced by perhaps just buying a new gear case and swapping out the innards, or can this sort of crack be welded? Second and more pressing issue is, can I run the motors safely for now, or am I on the edge of ending up with two defunct engines 10 miles from land at any moment? I would really like not to have the boat out of service for the rest of the summer. Anyone else had this issue? I have no idea how the cracks developed but understand from Mr. Google that I am not alone.

Thanks
Click to expand...


An aluminum casting is porous and laced with pockets of impurities & tough to weld when new. Add some salt corrosion
and a little gear oil, the labor to grind, clean & weld will possibly be a wash with the cost of a new housing. I just spent 2, 10 hr days tig welding a 6" crack in my Suzuki anti cav plate. (caused by some don driving SOB in the harbor) Good luck on your repair & let us know how it turns out.


:beer :beer
Click to expand...

Should read Non Driving SOB :wink:
 
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