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JimGo
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USA
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Initially Posted - 04/28/2012 : 19:37:03

I tore apart my BF8A engine's cooling system late last week in the hopes of replacing the impeller and changing the oil before we launched yesterday (see my other thread - the launch didn't happen due to weather). I had a bear of a time, incluing a bolt whose head snapped off as I was taking everything apart, and a crusted up bushing (the thing that the impeller rides on). I finally got everything assembled on Wednesday, including the oil change and the flush system described in the Tech Tips (thanks to everyone who suggested where to find appropriate replacement parts for that!!). I took it out to the yard on Thursday evening, hooked up the flush system, and there weren't any leaks. Plus, water gushed out the bottom (the intake) and out the "indicator hole".

I had a large trash can under the engine, and let the water pour out the engine to fill the trash can until the caviatation plate was under water. I then disconnected the hose, hooked up the (nice, fresh) gas, and after a few tries (operator error), the engine started right up. Unfortunately, there was no water coming out of the indicator hole. I quickly hooked up the hose again, and let it cool the engine down, then shut off the engine and tried to figure out what the problem could have been. The only things I could think of were that the cooling tube wasn't installed properly, and that I had somehow installed the impeller wrong. Out of curiosity, I started the engine again with the water hose still attached, and watched the water come out the holes. I then pinched off the hose, and the water stopped. I disconnected the hose, and could feel air being pushed through the hose. I connected the hose, let the engine cool off a bit, then disconnected the gas and let the fuel run out from in the carb.

I dragged the engine back inside the garage and carefully tore apart the lower unit again. It was getting late, and I was very anxious to make sure that everything went OK for my launch (since I might have been single-handing back to the new dock). I remembered as I took the unit apart the first time that the copper tube that feeds water from the pump to the engine had appeared to not have been installed properly (it hung off at a weird angle), and although I thought I had been careful when I did the assembly, I suspected that I hadn't put that together properly. I carefully dropped the lower unit and confirmed that, in fact, the copper tube had properly been inserted into the water pump. I also confirmed that the impeller was properly installed.

As I sat there dumbfounded, I think I hit on what had happened. I bult a stand for the engine, and the engine sits up fairly high, which made it nice for working on the lower unit. However, the way the engine sat also allowed the cavitation plate to sit at a fairly steep angle (a good 20-30 degrees) compared to the surface of the water, with the "forward" part of the engine hanging high (assuming the propeller end is the "aft" end). I had already put a lot of water into the trash can before it reached the cavitation plate, and I don't think I had completely submerged the forward end of the cavitation plate. Even with all the fiddling I did, I'm not convinced I had enough water in there at the end of my testing to have submerged the entire plate, let alone the water pump.

Yes, I know that's a lot of back story - sorry - I thought it might help with answering my questions. In looking at the repair manual for the engine, it shows the water coming in through the intake under the cavitation plate, then somehow magically entering the water pump. I searched the innards of the water pump, but I can't for the life of me figure out how it gets in there. Does anyone know where the hole is that lets the pump actually get water? Is it possible that everything WAS correctly done, and that I was pumping air simply because the engine wasn't deep enough in the water? The gasket that the copper tube sits in seems pretty shoddy - could a bad gasket cause this kind of behavior?

To finish the story, I carefully reassembled everything again, making sure that the copper tube was properly inserted into the water pump (including into the rubber gasket). Then I went to insert the pin that links the gear shaft to the shifter, and it slipped out of the pliers I had been using, and fell into the hole that the shifter lever goes through. I (incorrectly) thought the hole went all the way through the engine, so I dropped the lower unit yet again, and couldn't find the pin. I re-traced everything, and found it sitting just above the hinge. It was gummed up with grease, and I had a HORRIBLE time getting it out. An hour later, I finally managed to get it to drop onto the floor. Thinking I had learned my lesson, I took the engine off the stand and laid it down (so gravity wouldn't pull the pin into the tube), then tried to repeat the installation process. Somehow, I still managed to lose my grip on the pin, and it fell into the engine. I tried a few different tools to grab it, and only succeeded in pushing it farther into the engine. After another hour (which included turning the eninge over a few times and shaking it), I finally got the pin out. I was MUCH more anal about everything this time, and got it in place without losing it. That's when I tried shifting gears, and realized that all the shaking and moving had allowed the connector on the head of the shift rod to turn. Another 20-30 minutes of tweaking, and it seemed like everything was back in one piece. But, now it was after 2 AM, and I was exhausted. I never did get to test out the engine. Since we didn't launch, I brought it home with me and will be testing it again tomorrow or some time during the week - I left the fuel tank (and hose) at the boat, so I'll have to figure out what to do.

- Jim
Formerly of 1984 C25 named Dragon Wing

NOTE: In my case, PLEASE don't confuse stars/number of posts with actual knowledge. On any topic.

Edited by - on

Stinkpotter
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Djibouti
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Response Posted - 04/28/2012 : 19:48:57

Jim... Jim... Should I tell you what my Honda dealer charged for each year's commissioning? Probably not. Carry on...

Edited by - on

JimGo
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Response Posted - 04/28/2012 : 19:51:06

LOL...yeah, after this exercise, I decided that I'm going to leave this to the experts next time. It it hadn't been for that &@8% pin, I'd have been fine!!!

Plus, as I was taking everything apart, I was surprised and disappointed that this had been done by a pro the last time. I have the receipt from the work the previous season, so I know it had been done. But I think the guy just replaced the impeller, not the bushing. And the bushing NEEDED to be replaced.

Edited by - JimGo on 04/28/2012 19:54:16

Sloop Smitten
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Response Posted - 04/29/2012 : 09:26:04

On the other hand Jim you now have a good deal of knowledge regarding the engine. After you get through the trial and error part of the effort the risks of doing your own work substantially reduce plus you know the quality of work being performed. Anytime you can take advantage of offsetting a few boat units by tackling your own repairs is a worthwhile investment in my book.

Edited by - on

Voyager
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Response Posted - 04/29/2012 : 10:00:23

Jim,
I got a taste of that last week with the clock counting down to Friday's launch. Everything went wrong. Proves the point, when in doubt leave it to the experts. I don't live by that rule and pay for it regularly, but often, find myself saving all the parts and calling the guy.
This time I got lucky and did more good than harm. Just because we know how to use a wrench and a bigger hammer doesn't mean we always should!

Edited by - on

islander
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Response Posted - 04/29/2012 : 10:28:09

<blockquote id="quote">quote:<hr height="1" noshade id="quote"> But I think the guy just replaced the impeller, not the bushing<hr height="1" noshade id="quote"></blockquote id="quote">
More than likely. Don't ever think a mechanic is going to do the compleate job. They will cut corners to keep up with the work load that they have. It was easier to just slam in a new impeller and leave the bushing for the next guy or time. This is the main reason that I do all of my own maintenance. I do a better job because its mine and I'm not under a time limit. I also know what I did and what needs attention. Granted I'm very mechanical and this all comes easily to me. Jim we were all born stupid and slowly learned everything we know and when you finish this you will 'know how'

Edited by - on

JimGo
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Response Posted - 04/29/2012 : 20:49:28

If it hadn't been for that stupid pin, it really wouldn't have been that bad. I still need to get out and test the engine, but I need to figure out how I'm going to get it some gas first.

Edited by - on

TakeFive
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Response Posted - 04/30/2012 : 06:04:10

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 Jim... Jim... Should I tell you what my Honda dealer charged for each year's commissioning? Probably not. Carry on...
<hr height="1" noshade id="quote"></blockquote id="quote">
As you've undoubtedly seen from another thread, I'm paying the price now for a botched DIY job on my Honda outboard.

However, even when it costs more in the end, there are long term benefits to learning to do repairs yourself. Repairs during the in-season peak time often can have long lead times at the dealer. Several years back my Force outboard had problems with a crudded up carburetor while I was on vacation. I called the local dealer at Lake Wallenpaupack and he told me it would be a 2 week wait. (I was shocked, since he had given me same-day service a few years earlier.) Since my vacation was only one week, this was no good. I taught myself how to take apart the carburetor and clean it myself. (Sure enough, there was a spec of crud right on the needle valve.) I've cleaned the carb a couple of times since then, and each time I saved about $70.

Edited by - on

JimGo
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Response Posted - 05/02/2012 : 17:35:32

Ok, I finally got a chance to hook the engine up again, and it's still doing the same thing. I SWEAR the impeller should be installed properly, but all I get out of the telltale is some exhaust. I can't, for the life of me, figure out why I'm not getting any water out of the water pump. When I hook up the garden hose to the engine flush thingy under the hood, I get a nice flow out the telltale. I also get water flowing out the water intake. So, where could I have gone wrong? I am 100% sure the copper pipe is connected into the pump, and the gasket is there around the pipe, too. Any ideas?

Could I put some silicone around that pipe/joint?

Edited by - on

TakeFive
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Response Posted - 05/02/2012 : 17:57:13

Did you install the little keyway on the slot in the shaft to make sure that the impeller rotates with the shaft?

Also, I am not sure how much suction the impeller design actually has. In order to make sure you have a good prime, the water intake should be a couple inches below the water - basically low enough that the TOP of the impellar is below the water level. You had mentioned that due to a tilt of the motor, this might not be the case.

The only other thing I can thin of is the possibility that a screen on the water intake is crusted up, preventing water from coming in.

Edited by - on

dlucier
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Virgin Islands (United Kingdom)
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Response Posted - 05/02/2012 : 17:58:55

Might you have a clogged water passage or tube?

Edited by - on

JimGo
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Response Posted - 05/02/2012 : 18:18:52

Rick,
I'm not sure what you mean by the keyway. I noticed that the impeller had a D shape inside, and I made sure that aligned with the shaft.

Don, I had the same thought, but since I see water flowing, I'm a little confused as to where the clog might be. Unless it's right at the very inlet.

I'll tear it apart one more time... UG! But I'll start at the inlet...

Edited by - JimGo on 05/02/2012 18:19:59

GaryB
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Response Posted - 05/02/2012 : 18:47:18

Sounds like you might be missing the key that goes in the keyway. It's probably a half moon shaped metal key similar to the one in this link. The rounded piece goes down in the shaft and the straight side fits in the impeller.

Without the key the shaft turns but the impeller doesn't. Hooking up the hose forces water past the vanes and you get the telltale pee stream.

http://www.sterndrive.info/outboardmotor/impeller_key_pin.html

Scroll down to OEM #308928 -- #89595 Key

Edited by - GaryB on 05/02/2012 18:49:33

JimGo
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Response Posted - 05/02/2012 : 19:03:00

<<<edited to better explain the pictures>>>
OK, I have it disassembled.

In this first picture, you can see that the shaft is keyed. The thing that looks like a shaddow on my hand is actually the key/flat portion of the shaft.

And in this second one, you can just make out the flat part on the inside of the impeller. It's at about three o'clock in that picture. That flat part (the key) engages the shaft, and unless it is properly aligned, the impeller won't fit over the shaft.

The impeller and shaft mate pretty tight, so I'm not sure I see where the key would go; I don't think it's needed here. But if I'm wrong, PLEASE let me know!

As I was looking at everything again, I noticed, behind the shaft (toward the front of the engine) the housing has some divots in it. Could that be the problem? If so, what's the best way to fix it?

These last two pictures help illustrate the divots.

Edited by - JimGo on 05/02/2012 20:53:58

JimGo
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Response Posted - 05/02/2012 : 19:09:25

By the way, as I pulled the gaskets off, I noticed that there was a chunk of the old gasket under it. But I'm still a little confused. Wouldn't the divots allow the impeller to draw more water, since they are under the gaskets (effectively creating a different water intake)?

Edited by - on

TakeFive
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Response Posted - 05/02/2012 : 20:18:10

It's hard to tell for sure from the pics, but it looks like your shaft has a flat spot, and your impeller has a flat part that is bigger than the hole. Unless a key is inserted in there to fill the void created by both, the shaft will spin in the impeller without moving it.

My key is a little half moon shape that fills slots in the shaft and in the impeller. Looks like your key is a different design.

Edited by - on

JimGo
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Response Posted - 05/02/2012 : 20:42:25

Rick, in the end, you may be right, and just to be perfectly clear, I sincerely appreciate the feedback (rather have the feedback than not). But when I was assembling everything again, I grabbed the impeller and rotated, and the flat part engaged the flat part on the shaft, and caused the prop to spin. Did I put a huge load on the impeller? No. Could the shaft be rotating inside the impeller? Yes, that's still a possibility. But from the feel of it, it seemed like a pretty "positive" interface.

Edited by - on

JimGo
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Response Posted - 05/02/2012 : 20:56:27

Now that I have everything assembled again, I also wonder if that bushing is sitting too high. Perhaps the water isn't able to enter the water pump.

Yes, I know, I'm just grasping at straws...

Edited by - on

TakeFive
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Response Posted - 05/02/2012 : 21:14:51

It was hard to tell from the pics. I was just reporting what it looked like to me. If the impeller engages the flat spot without a separate key, then it's probably something else. If you want to be sure, you might want to try to get hold of a service manual and see if you are missing a part.

[EDIT: After looking at the pic of the impeller again, I now see the flat spot on the impeller, and it looks like it should engage the flat spot on the shaft. The glare was deceptive so I didn't see it the first time.]

Edited by - TakeFive on 05/02/2012 21:16:12

dlucier
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Response Posted - 05/03/2012 : 05:36:29

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by JimGo
 By the way, as I pulled the gaskets off, I noticed that there was a chunk of the old gasket under it. But I'm still a little confused. Wouldn't the divots allow the impeller to draw more water, since they are under the gaskets (effectively creating a different water intake)?
<hr height="1" noshade id="quote"></blockquote id="quote">

Hmmmm? The black tar stuff near the front on the housing looks like exhaust residue so the outside of the housing must vent the exhaust with the center of the housing aft of the shaft being the intake water passage. That divot, or divots, (galvanic corrosion) there between the two passages could be venting air (exhaust) into the water jacket thereby breaking the suction/prime for the impeller. This might also explain the exhaust coming out of the water telltale.

You indicate there was extra gasket material there. I wondering if this filled the divot gap enough to make a seal between the two passages???

Just thinking...

Edited by - dlucier on 05/03/2012 08:25:36

Sloop Smitten
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Response Posted - 05/03/2012 : 08:40:58

Jim,
If I understand you the tell-tale flows when hooked up to the flush kit but not when the engine is running. So the channels to the tell-tale are open but no water is coming from the pump. Could it be you have a blockage in your water tube? You might hook up the flush kit with the lower end off and see if you can blow that tube out. Make sure water is flowing through it well. Other than that the only thing I can think of is the impeller is backwards or the water tube is not seating correctly in the pump housing. There aren't any other parts that control the water flow except for the main drive shaft. Did you confirm the propeller is not free-spinning when you put the outboard in forward? Maybe the drive shaft is not seated correctly.

Edited by - Sloop Smitten on 05/03/2012 08:56:06

Sloop Smitten
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Response Posted - 05/03/2012 : 08:54:42

<blockquote id="quote">quote:<hr height="1" noshade id="quote">By the way, as I pulled the gaskets off, I noticed that there was a chunk of the old gasket under it.<hr height="1" noshade id="quote"></blockquote id="quote">

There is suppose to be a paper gasket on both sides of the metal shim. If you are missing the bottom one that might contribute to a loss of water pressure. You could repair the indentations with some JB Weld and formulate a gasket out of RTV if a repacement is not readily available.

Edited by - Sloop Smitten on 05/03/2012 08:57:45

Joe Diver
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Response Posted - 05/03/2012 : 11:19:03

My untrained and purely humble opinion is the lower unit needs to be replaced....unless that center section somehow comes out and is a replaceable item.....

Edited by - Joe Diver on 05/03/2012 11:19:27

TakeFive
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Response Posted - 05/03/2012 : 12:00:41

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Joe Diver
 My untrained and purely humble opinion is the lower unit needs to be replaced....unless that center section somehow comes out and is a replaceable item.....
<hr height="1" noshade id="quote"></blockquote id="quote">
I think it may be time for Jim to seek professional help...no, not THAT kind of help

, but a visit to his friendly Honda dealer for some professional TLC. Let them decide whether the lower unit needs replacing.

As I mentioned in the other thread, my experience with the guys at Hilton Marine in Wilmington was pretty positive, although there may be other dealers closer to Jim's home or marina.

Edited by - on

islander
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Response Posted - 05/03/2012 : 14:08:20

Jim your impeller is Hondas earlier design. You don't have a key way but instead have the flat spot on the shaft. Your impeller should be D shaped also on the inside to fit that flat spot. Honda switched to the key way later on. This seems to be confusing you and others on this thread. On the top of the pump housing where the water tube slides into the pump there should be a rubber cap that creates a seal between the water tube and the pump. Sometimes when you pull the lower unit off that seal will remain on the water tube instead of on the top of the pump housing and you might not know to look for it on the water tube. You just slide it off the water tube and put it back on the pump housing before putting the lower unit back on. Without that seal water will just squirt out of the pump at that joint. Also Don has good eyes on that corroded wall between the exhaust and the water. Not good.

Edited by - islander on 05/03/2012 14:35:27

JimGo
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Response Posted - 05/03/2012 : 20:24:05

Thanks guys. Rick, I agree, it's time for professional help. My boat was put in the water today, and I dragged the engine down to the boat and slapped it aboard for a 3-4 mile trip to my new marina. The engine started up on the 1st or 2nd pull, and gave me a nice stream out the back! I was THRILLED! However, as it ran, the stream decreased some. I'm now thinking that the thermostat may be corroded. Anyway, I did manage to get some water flowing through the indicator for the entire trip, which was good. But it isn't flowing the way it should, and at this point my efforts are better spent on something else.

Scott (JoeDiver), I'm afraid you may be right, a new lower unit may be needed. That shouldn't cost much, right?

Edited by - JimGo on 05/03/2012 20:28:15

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