honda 50A outboard electrical problems

[81venture]

Check your prop seal for corrosion while you have it off...

My new to Me X last season the lower unit cracked on the side...apparently quite common on those...if run in salt corrosion builds between the ring that holds the prop seals in expands and will crack it..

I had mine professionally fixed and re-welded to the tune of $300

[Catigale]

Tom, I would just epoxy that back in there and save the risk of Helicoiling that thin metal

It's all shear on that bolt, almost no tension load at all.

[paul I]

My problems started after motor overheated because the water outlet was clogged. In itself it is not a big problem, very easy to fix, which I did, by cleaning and eventually replacing the fitting, but it was too late. Does any one know if this is a normal condition (i.e. no audible alarm on overheat) on Honda 50 HP 4-stroke outboards?

I'm sorry I'm so late to this party. Not long ago I finished some work on the lower unit of my BF-50. Last year I also had a problem (since solved) with the temp alarm.

By a "clogged water outlet" I assume you are talking about no water coming from the "pee hole indicator" (henceforth called "the indicator"). A clogged indicator in and of itself will not cause an overheated motor. The indicator is just that, an indicator. It is meant to give a visual indication that the cooling pump is providing cooling water to the engine. Clogging that hole does not stop the cooling pump, it just no longer provides the indication. The alarm will not go on simply because the indicator becomes plugged. It goes on when the temp sensor activates and becomes grounded, which completes the circuit to the alarm and it sounds.

Regarding the alarm, my problem was a loose connector in the remote control that I caused myself when replacing the throttle and shift cables. Tomfoolery supplied me with manual excerpts that I used to troubleshoot it. Tom, have you opened the remote and measured voltage at the buzzer connection during a test? If I recall the engine had to be on to do this. I think there is also some mechanism that prevents the buzzer from sounding at idle. The throttle had to be open some. Even now if I idle the engine and raise the motor out of the water the alarm will not sound. If I increase the RPM it will. The red led is on at idle (I think but not positive on this). It all works perfectly now... one valve cover and two impeller changes later.

Regarding milky lower unit oil. Three seasons ago I changed the oil and found it milky. I took the lower unit to a Honda dealer and had the seals changed. The next season it was less milky, but still milky. Changed the oil again. The next year even less milky... but still some. Last year I used the motor very little and had only a trace of milkyness. I am unsure if this is just residual water in the gear case or if there is still some water getting in past the seals. I even question if the milkyness is actually due to water infiltration. I took the used oil and let it sit in a clear jar for months thinking that the water would eventually separate. It never did.

[Tomfoolery]

Tom, I would just epoxy that back in there and save the risk of Helicoiling that thin metal

It's all shear on that bolt, almost no tension load at all.

Too late. But rather than using a helicoil, I ran a 7/16-20 tap in there, which is extremely close in pitch*, and only slightly larger diameter than the M10-1.25 that was originally in there. So I basically cut the threads slightly deeper. Got very little metal, but it cut deep enough to show clean metal. I measure the wall thickness and actually drew it up in CAD (of course ), then overlaid the larger thread form, just to visualize how metal would be removed, and it was a lot less than drilling and tapping for a helicoil.

I was lucky in that the M10 and 7/16" were so close in diameter and pitch. So now I have some metal, rather than some caulk, holding the bolt in. Or I will, once the bolts come from McMaster, as 7/16" fine thread in stainless is not something most places carry.

I also chased the other metric threads with a metric tap to clean the white corrosion detritus out.

The lower unit has held as it was at least since I got the boat, when the shop that surveyed the engine and changed the water pump (once I completed the purchase) told me there was a problem with one bolt (but they didn't tell me they glued it in with caulk). Just one of many reasons I don't trust most other people to do work for me.

*M20-1.25 has a pitch of .0492". A 7/16"-20 thread has a pitch of .0500". .007" pitch error in one diameter is acceptable (to me), especially considering the bolt was doing exactly zip before, and even after two diameters, there's still metal engagement.