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Honda BF 50 Inspection

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06Harleyultra

New member
Hello forum members,

I am a nube when it comes to out board engines. I have an opportunity to buy a boat with a 2002 Honda 50 on it. Per the owner, it runs fine, and has been dealer serviced regulary. It has been run in salt and fresh water, and only run 2-3 times over the last year.

After looking over the forms and previous automotive experience, I am (dangerously:confused:) confident in doing a very basic inspection. Runs vs not, peeing well, inspect inside cover, review service records, and run it up on the water, ect.
My plan is to replace the impeller assembly complete, along with t-stat, and flush when I get her home. (along with a service manual).

Can anyone help with gauging the Hours? (no meter), and Big points to cover?
Thanks for any and all help.
I look foreward to getting help here, and returning the favor when I can.

06Harley
 
I think you are thinking the right way.

Ideally, a compression check would be good. However, everyone does not have those tools available. Maybe, at least look at the spark plugs. They should look very clean and not oily...and should all look about the same.

The two main things you mentioned are reviewing service records and on the water test. If the owner has changed the oil and gearlube yearly, and has enough care to keep the service records...that says something there.

The main thing will be a good on water test. Not just a back into the water and run for a couple of minutes. A half hour test should tell you if there are any issues. Stop the motor while you are out, then restart to see if it easily restarts. You should be able to get 5500 rpm or so at full throttle. Much less and it is over propped.

There is no way that I know of to know how many hours are on this motor without an hour meter.

The 50 HP is a workhorse and can take a lot of abuse. That is typically what is used on workboats around here...and in spite of all the different guys running them....they keep on ticking.

Unless the service records indicate that it just had an oil and gear lube change. I would also do that with the impeller, etc. if you buy it. Do not forget to change to fuel filter. Also, as a practice, be sure to use a good fuel treatment like PRI-G, Stabil-Marine, or equivelant. They are fuel stabilizers that have additives in them to help clean the carburator passages, decarbonize the engine, fight the effects of ethanol. Use it with every fill up. You will not regret it.

As long as the plugs look ok, I would not worry about them. Make sure they are NGK DR7EA. Not Denso or some other brand. NGK's work the best in Hondas.

I think you will be very happy with that Honda.

Hope others jump in to give their two cents worth.

Mike
 
I have a 1999 Honda BF50 that i've run for 7 years and put on about 1500 hours.
I change the oil and gear lube regularly , plugs every other year.
Great reliable motor.
They don't like cold temps, but once warmed up will run like a top all day.
 
I don't have any experience with this outboard and hondadude pretty much gave you all you should need along with your automotive expertise. I just wanted to say that I have read here on the forum, more than once, about these having an ignition problem and it not being discovered until the guy pulled each spark plug one at a time while the engine is running. I believe I've read, in all cases, new plugs solved the problem.

I've even noted how smooth the twin Honda's will start and idle with a dead cylinder and it amazes me! 50% down on power and still pulls and runs reasonably well! So, with a triple, a problem can be masked because of the great balance and precision that is put into the manufacture of this outboard.

So, if the seller will let you, you might want to perform this simple test to eliminate any weak cylinder or firing issues before you buy.

As far as buying a Honda, I work on close to 100 of them for a rental fleet and, although none of them are 50 hp, I can attest to the ruggedness and quality put into each one. Honda just makes great outboards!
 
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Thanks for the info and tips everyone:cool:
I will definately pull the plugs and inspect, but am unsure how to accomplish this with a running motor. Pop off spark plug boot's and listen and feel? Or something else? What size ratchet/socket will I most likely need? I have to travel about 4 hours away on Sunday to do this, so being prepared is a must.

Thanks Hondadude for the NGK tip...some engines are like this, and it's no big deal ONCE you figure this out. LOL
I will post a reply sometime next week with observations and opinion's, as this may help the next dude down the road.

06Harley
 
There is a way to determine the total running hours on your engine, as a former honda dealer a well equiped shop will have a computer to extract engine pramaters and preform a health check.
 
There is no computer, per se, on the 50 HP carburated engine. It is run by a CDI unit. Therefore, you can not connect a computer to it. There is a computer, if it were one of the new EFI models.

I will have to check on the spark plug socket size.

To do a cylinder drop test, you should have the motor running either in the water, if you can get to the spark plugs, or on a hose. You have to be careful running that motor on a hose, with a rabbit ears attachment. There is a third water intake under the horizontal plate that is above the prop. You will need something like duct tape to tape that up, so it does not suck air and overheat the engine. So take some duct tape.

Make sure you have insulated pliers or plastic fuse remover pliers. Just pull the plug wire off of each cylinder, one at a time.

You should only need to pull it off a couple of seconds. Listen for the engine to run a little rough or lower in rpm. Then hold the spark plug cap just over the spark plug and listen for the ticking of the spark. When you put the plug wire back on, you should hear the engine speed pick back up and smooth out. Then go to the next one.

I suggest you listen for the ticking, that way you know it there is spark.

Mike
 
Hondadude,

What happens if you pull the spark plug wire and notice a difference but not the same as the other cylinders. Is it usually the plugs that should be replaced first? If so and done so, and you get the same results, what then?? Reason I ask is my friends motors has a similar problem. What would be the process of elimination with regard to testing or solving the problem. do the spark plug wires go bad?
 
If the sound is different, but it is still dropping in rpm's...

Listen for a difference in the frequency of the sparks.

Change the spark plugs.

If not change, take a compression test to check the quality of the cylinder.

Check anything that has to do with the different cylinder (although, it may be the good one).

Check idle mixture screw adjustments, if you do not have the locking caps on them.

Check the carburetor vacuum balance.

If it is really old, then spark plug wires may be a factor....I have never changed any on a BF50 in 15 years. Not to say that they could not be a problem....but....

The difference will probably not be exactly the same in any case.

If if does not drop, there are some other things to try depending on the motor.

Mike
 
Well,
The motor ran pretty well, at all speeds, pee'd well, and plugs ok (just old). She will get a good tune up here soon.
The problem I have: the lower unit has a Crack on the housing, on top of the propeller hub, about an inch long. Does not leak fluids, prop turns fine...
Can this be repaired, like welded ? (price was reduced when I bought), or does it have to be replaced (1100$).
What could cause a crack on top? I dont see any prop dammaged areas, skeg fine. Could this have frozen with tilt up and water trapped?
The PO had no clue it was even there until I pointed it out. (or if he did, was a good actor) LOL
Will provide more info if needed.

Thanks!!

Rich
 
I have 2 legs (from my BF40A's) that were cracked as well overtime. I took them in to a machine shop and had them welded. They haven't cracked since. Some of the mechanics here stated that this is a common problem with Honda's. Well I had 2 of them so far. Not sure statewide if this is a common problem.
But yes, I had mine welded.
 
Salt water can get in there and cause corrosion of the aluminum parts.----------Oxygen joins the aluminum to cause the white powder you see.----Something has to give.-----------A good cleaning and a good welder can fix it.
 
new problem same motor, just changed the oil and it was gray and reeked of gas.
I let it drain well and then replaced the oil and filter.
weird thing was the motor seemed to run fine with the contaminated oil ??
have I done any long term damage ?
any suggestions appreciated.
 
First check your thermostats. If stuck open, you are running too cool and condensation and gas leaking by the rings can contaminate the oil. If T-stats OK, do compression test. Maybe try decarboning the engine - discussed several times on this forum - to loosen up your rings. See posts from Skooter.

Long term damage? No telling!
 
All what chawk said plus....Dismount your fuel pump...leaving hoses connected. Squeeze fuel bulb and hold pressure on it while you check for leaks around the plunger. Fuel pump may be leaking fuel right into crank case.

Mike
 
While it's not good to overfill the engine with oil....I highly doubt that would have anything to do with it being gas contaminated. THAT is typically caused by either the thermostats stuck OPEN...as chawk_man said or the fuel pump leaking like Mike said. It is possible one or more of the carburetors is set RICH and that could do it too.

Overfilling the crankcase with oil is bad because the crankshaft journals can start "beating" the oil like a blender and cause it to be aerated or, in other words, "foamy". If the oil gets badly aerated because of this, it can lead to the oil pump not being able to pick up enough liquid oil and feed it to the bearings. The pump is a "gearotor" type and can ONLY pump liquid....not air. So, as a result, the bearings get quickly damaged due to lack of lubrication. It is WAY better to err on the side of be oil being a tad low than a bit high.

Good luck.
 
dark_star said:
$56 for a thermostat .... Yikes !
Click to expand...
You asked if the gasoline may have caused damage and yes, it certainly could have.Any dilution of the lube oil is dangerous. So, your plan of replacing the thermostat and "seeing what happens" falls short in my estimation. I think you and your engine would be well served if you were to perform the fuel pump leakage test Mike suggested BEFORE running the engine again.

If it passes THAT scrutiny, then replacing the stat and keeping close watch on your oil's condition makes sense.
 
jgmo said:
You asked if the gasoline may have caused damage and yes, it certainly could have.Any dilution of the lube oil is dangerous. So, your plan of replacing the thermostat and "seeing what happens" falls short in my estimation. I think you and your engine would be well served if you were to perform the fuel pump leakage test Mike suggested BEFORE running the engine again.

If it passes THAT scrutiny, then replacing the stat and keeping close watch on your oil's condition makes sense.
Click to expand...

fuel pump was detached and primer ball pumped
and no leaks .
will keep a watchful eye on the oil level.
 
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