BF75 Honda 4 stroke water issue?

fishnhuntnfool · 05-19-2009, 07:34 AM

The water outlet is coming out in a spray and seems to increase with rpm's, but it's not coming out in a stream. I don't know anything about boat motors, but am very mechanically inclined. I just need a little direction on what to look for. I know this could be an impeller, but I'm thinking more along the lines of an obstruction. Any help would be great, trying to get it ready for this weekend. I'm in Hillsboro if anybody wants to stop by and show me

Thanks!

GSD · 05-19-2009, 08:28 AM

Check the Pee-tube for bug nests. They can sometimes block the flow of water. Mud daubers are frequent culprets as their egg cases are hard, almost like concrete and water doesn't seem to break them up.

Take a piece of wire and run it up into the tube or take the tube off and try to blow through it to see if it is partially plugged.

fishnhuntnfool · 05-19-2009, 08:54 AM

I'm assuming the "pee-tube" is where it is spitting water out? When i poke anything up there it just appears to hit the exhaust pipe that's in there. Where do I take off the tube at? Where is the water pressure control valve? About the only thing I could find is a couple of black hoses one smaller one larger leading up to the impeller mounted underneath the pull start assembly. These led to a black cover on the right side (looking from the rear of the boat) then there was a hose that went from there to the other side of the motor. I took this hose off and it was clear... Thanks for the help!

fishnhuntnfool · 05-19-2009, 09:25 AM

I can't post a pic since I'm not at home, but there are two little holes at the top of the cover for the lower unit where the water is spraying out. If I take off the top cover and look down in that area, it's where the exhaust pipe goes into the lower unit.

I'm definitely green in the boat motor world so if anyone has the time to drop by tonight, I'll be home. Done plenty with cars and motorcycles, but boat motors are a whole new thing :-)

GSD · 05-19-2009, 09:33 AM

That would be the exhaust tube cooling water.

That is totally different from what I mentioned earlier. The Pee-tube is in the engine compartment itself and discharges water out a small rubber tube just outside the engine cover and is an indicator that water is flowing through and cooling the engine.

From your discription and the location of the water spray, that would be normal as I know it.

fishnhuntnfool · 05-19-2009, 09:37 AM

Great! So now I don't have any water flowing through other than the exhaust cooling

. Any idea where that pee tube would be located or what part of the motor it would be coming from? Thanks again for all of your help GSD!

GSD · 05-19-2009, 09:43 AM

Not sure exactly where it is located on the 75HP but it should be readily visible on the outside, rear part of the engine cowling. Generally a hose about the size of a large round pencil and it should have a stream of water flow when the engine is running.

fishnhuntnfool · 05-19-2009, 09:50 AM

I guess I should have mentioned in the first post, this is a 7.5HP motor, not a 75hp. Honda used the same model number for their motors but discontinued the 7.5hp and went to making the 75 hp sometime in the 90's. My motor is a first generation BF75. I'll look for the tube. Does the impeller make any noise when it's not working correctly, or is it just water flow that indicates that?

GSD · 05-19-2009, 10:09 AM

If your 7.5HP is like my 8HP the hose will be located discharging on your right hand side, looking from the rear.
I should have caught the "75" when you mentioned the pull start assembly.
Here's the black hose location on the 8HP Honda (1993 vintage). Hooks up on the left side of the engine and discharges on the right side. If your's is from the era of the white/blue colored HONDA outboards it's probably different...and I've not helped you out at all and time for me to get the tape out

, only room for one foot in there.

Yours may drop straight down like the one shown in this 7.5 HP parts diagram.

fishnhuntnfool · 05-19-2009, 02:03 PM

My did drop straight down like the picture and it was entirely packed with mud that would come out until I rolled and smashed the hose to get it to break up a bit. This will probably solve the problem, thanks a lot for all the help!

GSD · 05-19-2009, 02:12 PM

If you don't get any water flow from the hose after clearing the obstruction, stop your engine or serious damage may occur.

A little tip from past experience with the mud daubers: If you store your motor outside, place a Q-tip, cut in half, lightly in the opening on the hose, it makes a dandy bug blocker.