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Honda BF50 (5hp, pre-1997) Spark Plug Cap

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KevinClancy

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Hey Gang, I have a old, probably 1980's Honda 5hp outboard. I was changing the spark plug and the spark plug cap came off the lead wire. I can't tell if the cap is designed to come off, but I wouldn't think so. I put it back on and the motor started, but failed to run properly. It idles, but only if you give it full throttle and then it only sputters. Can anyone give me some advice on hw o properly install the spark plug cap? I am not very good with motor issues. Thanks! Kevin
 
Crunchy21 said:
https://youtu.be/N1Kubh1zk90
Click to expand...

Thanks. I've watched that video. It looks like my cap is different. It looks like it has a "point" that goes into the plug wire and not a clamp fitting. If I do any mods to the wire, I don't think that it will reach the plug. It's short. I might need to buy a new coil assembly in order to get enough plug cord length. The coil assembly is about $80 and the cap is about $10, so it not a lot of money, I was just wondering if I was missing something. I'll take a couple of pics when I get home tonight.
 
KevinClancy said:
Thanks. I've watched that video. It looks like my cap is different. It looks like it has a "point" that goes into the plug wire and not a clamp fitting. If I do any mods to the wire, I don't think that it will reach the plug. It's short. I might need to buy a new coil assembly in order to get enough plug cord length. The coil assembly is about $80 and the cap is about $10, so it not a lot of money, I was just wondering if I was missing something. I'll take a couple of pics when I get home tonight.
Click to expand...


The point you see up in the cap is actually a brass screw. So you push the wire in and turn the cap clockwise until you feel it snug up. If it doesn't snug up, you may need to trim just a little off the end of the wire, 1/8 to 1/4 max. Most of the coil packs are this way too, so if you like, you can replace with a compatible piece of plug cable.
 
OldHondaGuy said:
The point you see up in the cap is actually a brass screw. So you push the wire in and turn the cap clockwise until you feel it snug up. If it doesn't snug up, you may need to trim just a little off the end of the wire, 1/8 to 1/4 max. Most of the coil packs are this way too, so if you like, you can replace with a compatible piece of plug cable.
Click to expand...

Thanks! I think this explain it. I've never seen a connection like this. I'll give it a try tonight. Kevin
 
OldHondaGuy said:
The point you see up in the cap is actually a brass screw. So you push the wire in and turn the cap clockwise until you feel it snug up. If it doesn't snug up, you may need to trim just a little off the end of the wire, 1/8 to 1/4 max. Most of the coil packs are this way too, so if you like, you can replace with a compatible piece of plug cable.
Click to expand...

Well, I was able to get the spark plug cap back on, thanks to you. However, the motor is not running well at all. The motor will start, but no run for long. It also has no throttle response. It will not rev up when I give it power. Also, the plug is fouling after running for less than a minute. I don't understand how it can run fine one day, and now nothing.

Any suggestions on what I should try next? I don't have any experience repairing motors, but really want to learn.

Thanks!
Kevin
 
This all started when you changed the spark plug?? Was changing out the plug for "routine" maintenance or "just because it was time"? If that's the case, it would seem that you still don't have good contact with the plug wire and it's cap.

Or, were you changing the plug to improve a perceived problem? If that's the case, it's possible that the carburetor needs cleaning.

Or, the fuel isn't fresh and volatile.

These carbs are pretty easy to clean.

As a matter of fact, you might not even need to take it off and disassemble it. If you think it needs cleaning, do this first:

Find the "screw, plug" (item #8 in the link below) on the top of the carb and remove it. DON'T LOSE IT!
They don't sell them anymore!

Use the little plastic straw on a spray can of brake kleen or carb cleaner and spray into the hole. First try to point the fluid toward the front of the carb and then try to point it towards the back. There is a channel in there you're trying to flush out.

Do this with the spark plug removed and do it several times. Replace the scew plug.

Then, let everything sit for 20 minutes.

Then pull the engine over a couple of times with the spark plug out.
Reinstall the spark plug and try running it and see if there's any improvement.

https://www.boats.net/catalog/honda/outboard-by-hp-serial-range/5hp/bf5ah-la-pre-1997/carburetor

Good luck.
 
Last edited:
jgmo said:
This all started when you changed the spark plug?? Was changing out the plug for "routine" maintenance or "just because it was time"? If that's the case, it would seem that you still don't have good contact with the plug wire and it's cap.

Or, were you changing the plug to improve a perceived problem? If that's the case, it's possible that the carburetor needs cleaning.

Or, the fuel isn't fresh and volatile.

These carbs are pretty easy to clean.

As a matter of fact, you might not even need to take it off and disassemble it. If you think it needs cleaning, do this first:

Find the "screw, plug" (item #8 in the link below) on the top of the carb and remove it. DON'T LOSE IT!
They don't sell them anymore!

Use the little plastic straw on a spray can of brake kleen or carb cleaner and spray into the hole. First try to point the fluid toward the front of the carb and then try to point it towards the back. There is a channel in there you're trying to flush out.

Do this with the spark plug removed and do it several times. Replace the scew plug.

Then, let everything sit for 20 minutes.

Then pull the engine over a couple of times with the spark plug out.
Reinstall the spark plug and try running it and see if there's any improvement.

https://www.boats.net/catalog/honda/outboard-by-hp-serial-range/5hp/bf5ah-la-pre-1997/carburetor

Good luck.
Click to expand...

I started working on the motor because it had stopped running on my last outing. It died about 200 yards from the ramp. I checked the plug first, and it was fouled so I decided to replace the spark plug. It was then I noticed the cap was not securely fastened.

I thought it might be something with the carb. I'm going to follow your advice in the steps above.

Thanks!
 
Yes, try that.
But I can help you disassemble and thoroughly clean the carb if this "trick" doesn't work.
This is one of the most simple carbs to work on most anyone can do it with minimum tools.

While you're looking at it this time make sure that your choke cable is properly attached and is rotating the choke plate as you push and pull the cable
Make sure the choke plate holds the position that you select and isn't capable of opening or closing on it's own.

If the quickie flush doesn't work, I'll ask you to take pictures as you disassemble the carb as well as make certain inspections as you go.

YOU CAN FIX IT YOURSELF!
 
jgmo said:
Yes, try that.
But I can help you disassemble and thoroughly clean the carb if this "trick" doesn't work.
This is one of the most simple carbs to work on most anyone can do it with minimum tools.

While you're looking at it this time make sure that your choke cable is properly attached and is rotating the choke plate as you push and pull the cable
Make sure the choke plate holds the position that you select and isn't capable of opening or closing on it's own.

If the quickie flush doesn't work, I'll ask you to take pictures as you disassemble the carb as well as make certain inspections as you go.

YOU CAN FIX IT YOURSELF!
Click to expand...

BINGO! She's running!!!

I think I have some issues with both the choke and throttle rod. When you suggested to check the choke cable, something doesn't look right. I have a picture attached.

After a couple of pulls she started, but no improvement. Then I noticed when I turned the throttle it had no response. When I manually operated the cable, she roared back to to life. Now the throttle works just fine. Maybe it was stuck or something might be broken?

I need to adjust the idle next. I need more throttle than necessary to keep the motor running and not stalling. I'm reading the manual, but all ears to any tips about adjusting the idle.

I need to do a thorough cleaning of the carb soon tho too.

Thanks!
 
Yeah, I don't know about posting pictures. I've never tried it. But I don't think it's because you're too new. I've seen many posts complaining about having trouble putting up photos on this site. Probably just not an intuitive operation because most of the same people eventually get their photos posted.

As far as adjusting the idle, there are two screws. #5 and #7 on the parts page I sent. #5 is the mixture screw and #7 is the linkage fine tuner.

Since it's running, adjust #7 clockwise to increase rpm. When it's where you want the idle screw #5 clockwise until the engine starts to slow and sputter. Then, back up #5 approximately 1/2 to 3/4 turn or until the engine idles smoothly.

Non of these adjustments are hard and fast rules and it's perfectly ok to "fiddle" with the settings until you're happy.
 
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