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1997 BF8A

risingsun

New member
"I have a couple of questions.

"I have a couple of questions. First I bought this motor from a friend who up graded to a newer motor. Since he moved out of the country, I have had little contact in a year. OK enough with the back ground. Here's my question. Does this motor have a pee hole like my 175 Yamaha? I see a hose which comes from the Inlet Maniford and exits from the bottom of the motor case. After starting I saw no water and turned the motor off. I then dropped the lower unit and replaced the impeller pump. After I completed the installation I re-started the motor. All I get is some smoke from this hole. What is the purpose and should I get water from this hose? How do you know if your getting water to the motor? When I rev the motor in neutral, I see water bubbling in my 55 gallon barrel above the prop. I'm assuming it's the exhaust. My second question is what is the 1/4" inside dimension (guess by me) hose which appears to exit from the thermostat to the other side of the motor near the oil inlet cap? The motor starts fine and the green light stays on which I'm told is good. What can I do physically to see if I'm getting water up to the motor? The motor manifold and head seem hot to the touch after running for a minute. I don't want to damage the motor by running it until I hear from an expert. Thanks for any help I can get."
 
OK I read a few back comments

OK I read a few back comments and found most of my answers but still no idea what the hose from the thermostat to the nipple near the oil dip stick. I tried blowing into the hose but felt resistant so I took a piece of stiff copper ground wire and tried to poke around inside the nipple to see if it's plugged. From what I felt it does. Do I need to remove the motor and then the side plate which the oil dip stick is to see the stopage? Please help. Thanks
 
"They call that a "Bypass

"They call that a "Bypass Tube", water pressure from the impeller pump is open to enter the cylinder jacket by the 'nipple at the oil stick', but with thermostat closed, there would be not enough flow to cool the exhaust manifold.

Bypass water enters by the thermostat and a little goes out tell-tale hose and most cools and exits with exhaust.

When cylinders are warm, thermostat opens and water joins in exit from that point.

You could disconnect either end of that Bypass Tube and see water flow, if not, check water tube connection through extension case.

Pee-hole is usually first to get 'blocked' and by itself will not cause overheat, but is a symptom of possible blockage at Thermostat, Exhaust or lack of water pressure, which will cause problems.

If you have water pressure at Bypass, but no tell-tale, I would remove the intake/exhaust manifold and thermostat for cleaning.

New manifold gaskets (two) are available from boats.net, if they come up NA, telephone them as p/n's had changed on my similar BF100 and I had to make toll-free call to order proper p/n.

Water jackets around cylinders and in head can only be thoroughly cleaned by removing Cylinder Head. This is pretty easy to do, but then you should take the head to auto/marine machine shop for surfacing.

After you get the cooling done, check the valve lash adjustment for at least .005" clearance (an Annual/200 hour item).

[IN : 0.12+/-0.02mm (0.0047+/-0.0006 in.)]
[EX : 0.20+/-0.02mm (0.0079+/-0.0006 in.)]"
 
Thanks for the information. I

Thanks for the information. I removed the manifold and found the Thermostat caked with white stuff along with much of the passages semi plugged. I soaked the Thermostat and manifold in 50/50 solution of vinegar. It made for a easy clean up. I tried blowing into the bypass tube towards the nipple nearest the oil stick and felt like blowing into a bottle. Would this be normal since the water jacket is a closed chamber? I'll check and see if I missed the tube while stabbing the lower end to the upper extension tube. I ordered the gaskets which some had new part numbers already posted on Boats.net diagram. Thanks again for explaining in simple language for me to understand. I appreciate the time you spent helping me.
 
"Don't know about blowing,

"Don't know about blowing, but if you put water pressure to the bypass tube,
it should flow out the thermostat opening.

If the extension case water tube were not connected,
it would flow out the exhaust exit above the prop."
 
What I met was if I removed th

What I met was if I removed the bypass tube nearest the Thermostat and blew into the bypass tube would I feel resistance because of the chamber being closed? The direction would be towards the oil dip stick housing.Right now it's like blowing into a bottle? No movement. If resistance is felt then I'm OK and won't worry about removing the housing which the oil dip stick is part of the housing.
 
Never tried it and never had t

Never tried it and never had the dipstick housing apart.

Only way I could imagine not having a clear flow through would be if a check valve were included.

I do recall that they were modified from earliest versions to include an 'aperture' to restrict the water flow through the bypass tube.
 
"Thanks again Pilotart. I see

"Thanks again Pilotart. I see your from Florida. I spend some time in Boca Raton visiting my Daughter. Between visiting I'm fishing the ocean for Kings, Wahoo, Snook, Black Tuna and what ever comes my way.

I'll report my progress once the gaskets get here. I want to get the boat ready for Kokanee fishing our local lakes. I'm fortunate because I live within 8 great lakes only one hour away to the farthest lake,"
 
I have a 8hp & its not pu

I have a 8hp & its not pumping water I assume that is need a new impeller. how hard is it replace? & where is it located. Iam very handy when it comes to fixing things
 
"The impeller is located insid

"The impeller is located inside the lower section of the prop assembly. It's quite easy to replace. Look for the bolts under the cavitation plate which is above the prop. The bolts are under the plate. They are 10mm and can be removed with either a 12 point wrench or socket. You must first remove the motor housing and look for the 10mm bolt holding the wire harness and voltage regulator. Removing both bolts will make the job easier. Two bolts only so no big deal. Now lift the shift handle to the forward position from neutral. Once you have the regulator and harness bracket away then look for the pin holding the shift mechanism which is under the detent for forward, neutral and reverse. You can see the clevis and the cotter pin once you are in forward position. Be careful when pulling the pin so it doesn't fall in side the case. Carefully remove the clevis pin. You now remove the series of bolts under the cavitation plate. You might need to jar the unit a little to break the seal. I removed the prop from the shaft just to make it lighter and it made it easier to handle. The whole lower unit will drop down and you will see the water pump housing and a square tube which will stay in place unless you decide to take it out. I didn't. Once the unit is out look for a rubber grommet which is part of the housing. Mine stayed on the housing. Some times it will stay on the tube which you will need to look inside with a flash light. You must be sure to install this rubber grommet or your not going to have water pressure going up the tube. Remove the series of bolts and tap the housing until you can lift it off. Remove the impeller and check for scoring on the inside housing. If the impeller got hot and melted, you will need to clean the passages. The impeller has a flat spot on the inside so be sure to look for it. Once cleaned up and the impeller is in place, rotate the prop shaft clock wise while pushing down the housing. The vanes will rotate in position and the housing will fit securely. When you lift the lower unit back up be sure to align the square female to the male end and the water pipe to the proper port on the housing. Put a bolt on each side and get the unit flush to the lower housing. The shift rod which you removed the clevis pin needs to align with the yoke again. I used a small rod to position the yoke to the rod end then used a needle nose plier to insert the clevis. Now add the cotter pin and then replaced the remainder of bolts. Replace the two bolts which one is for the wire harness and the other for the voltage regulator. You can see a working diagram on this site.
Boats.com You can also buy parts from them also. They are much less expensive here but you will need to wait for delivery which some times can be over a week to ten days. Good luck.

Here's the link.

http://www.boats.net/parts/search/Honda/Outboard%20Engine/1997/BF8AM%20LA%20OUTBOARD%20ENGINE,%20JPN,%20VIN%23%20BACL-1200001/parts.html"
 
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