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1996 Honda BF50A

A

avidskier1973

New member
Howdy fellow boaters, I'm new to this forum and hoping to get some help with my Honda 50HP Fourstroke.
I purchased a used Rendova 14 with a 1996 Honda 50 hp four stroke. Before purchasing the vessel we took it on a sea trial and then out again after the deal was done and the Honda seems to have behaved well.
Later that day I brought it home and tried running fresh water through the motor with ear muffs but no water come out of the tell-tale which worried me. I didn't happen to notice whether or not the engine was peeing when we had the boat on the water (I assume so.)
I'm not a certified mechanic but have a basic understanding of engines and started to dig around the old interweb for possible issues. Some of the information suggested I look at the thermostat and impeller/water pump. First I poked around the tell-tale connections to the engine and made sure nothing was obstructing flow. Purchased a new thermostat (the old one was cruddy and probably seized). I also ran some water through the thermostat housing (when I had the lower unit off) to make sure nothing was clogged and water did come out through the bottom. I checked and also replaced the impeller (the old one was not in bad shape) but for under $100, for both parts, I took care of two potential issues and gave myself some additional peace of mind.
I put everything back together and initially, there was a good stream coming through the tell-tale. Shortly after, I assume when the engine got up to temp and idling, there wasn't much water coming out of the tell-tale. I did submerge the lower unit up to the anti-ventilation plate inside a large bucket.
The question is, do I have a bigger issue? Should I remove the water jacket and check for additional obstructions or salt deposits that may be clogging the cooling system?
The boat spent most of its life in fresh water and was tender for a sailboat in NY and owned by the same family. It's been in the saltwater for the last couple of years. The owner assured me that it had been flushed after each use and he did have some maintenance records to prove the engine was taken care of. I did also read that the tell-tales are finicky on these motors but after performing the service, and checking for obstructions, I'm at a loss.
Any thoughts would be appreciated.
 
I have limited experience with the 50. But when I was helping some friends service theirs. I had the same problem. When we dropped the lower end in a large trash can of water, it wouldn't pee. Apparently, air can get trapped in there and keeps the water from circulating. To fix that, we raised and lowered the motor several times while at idle. Be sure that the water level is as high as possible on the lower unit.

Another possibility is that the outlet to the indicator hose is clogged. Run a piece of weedwacker mono in an out. Or, better yet, disconnect the hose where it exits the engine and clean out the nipple that the hose attaches to.
 
chawk_man said:
I have limited experience with the 50. But when I was helping some friends service theirs. I had the same problem. When we dropped the lower end in a large trash can of water, it wouldn't pee. Apparently, air can get trapped in there and keeps the water from circulating. To fix that, we raised and lowered the motor several times while at idle. Be sure that the water level is as high as possible on the lower unit.

Another possibility is that the outlet to the indicator hose is clogged. Run a piece of weedwacker mono in an out. Or, better yet, disconnect the hose where it exits the engine and clean out the nipple that the hose attaches to.
Click to expand...
Thank You, chawk_man
 
This is a pretty common problem with most all outboards.

Twigs, grass, pebbles and other small debris will get in the tell tale bypass passage and can bounce around in there letting it pee sometimes and blocking it at others. I'm not a big fan of the weed eater line technique. Yes, it does work sometimes but, often, when you do that it just shoves the crap down inside the passage. It might work for awhile and then clog again. It can drive you nutz!

If you really want it clean and reliably peeing you will need to do some work.

Another thing that will be a problem is the little hose that connects the tell tale fitting in the block to the little nozzle on the side cover. That hose NEEDS to be SOFT, SUPPLE and FLEXIBLE to allow debris to pass. The hose gets hard over time and, where there's a bend in it, will clog because it won't flex. It should be replaced every few seasons. If it's not "wet noodle limp" in your hand, replace it. I have also enlarged the opening in the nozzle.

The hose can also be routed wrong and get pinched when the side cover gets screwed down. Watch that carefully.

Take the side cover off. Take tube off the nipple at the engine block. Remove the nipple from the block.

With the nipple out and the outboard leg submerged in a tank of water (trashcan) start the engine. Stand back! Because it's highly likely that LOTS of water will gush out with great force and shoot several feet. If it does, your passage is clear. Screw the fitting back in the block, put the hose back on the fitting and the side cover back paying VERY CLOSE ATTENTION to how that hose is routed to the nozzle on the cover. Ensure that the hose isn't pinched or kinked shut when the cover is in position.

If water doesn't GUSH out as if from a small fire hose, shut the engine off and work your weed eater line down into the passage to break things up in there. I prefer using compressed air instead. Won't hurt a thing. But either way can work.

Start the engine again and stand back. I've never seen that not work to clear a tell tale passage and keep it clear for a good, long time.

But....it's an outboard....crap is floating in the water....so....it WILL get clogged again.... ...eventually.

Your job as a boat driver is to keep an eye on that while you're doing your check for traffic to the rear.

Good luck.
 
The others here have some good advice, which may well solve your problem.
You said [ I did submerge the lower unit up to the anti-ventilation plate inside a large bucket]
AFAIK the BF50 has a third/upper water inlet on the underside of the cavitation plate.
If the lower unit is only submerged in a bucket up to the cavitation plate, there is a good chance that third/upper water inlet will suck in air instead of water and the engine will slowly overheat and the water pump will also overheat because it's being run dry. The water pump impellor will be destroyed and the water pump housing will overheat and become distorted.
I know this because I've done it myself on a BF45.
The water level must remain above the cavitation plate to avoid this problem.
Hondadude has advised that when flushing these BF40/45/50 motors on muffs, to tape over the water inlet under the cavitation plate while flushing to prevent overheating. Although personally I've never had to tape over that third/upper inlet when flushing on muffs with good water/hose pressure.

Bob
 
I believe @bobmech has it.

1. not enough water in the bucket. I would suggest a water level well above the cavitation plate, high enough to submerge the pump at absolute minimum (3-4" above plate?).
2. The 3rd water intake, located directly above the prop, causes all sorts of problems if you aren't familiar with the motor.

To run it on muffs, you need a very good supply of water as much of it is going to run right out that 3rd intake above the prop. The plan, assuming you have a good supply of water to the muffs, is to not run the engine much over an idle (while on muffs). Any faster and the 3rd port is going to suck air and you're going to smoke your impeller and housing....

Best of luck with the new motor! -Al
 
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