Clearing clogged waterways in Honda BF8D?

bmacpiper

Posted a while back (8hp impeller, below) regarding my impeller blowing up. Lots of chewed up rubber fins in the intake, etc. Finally replaced it yesterday.

Unfortunately, there is still no water at the telltale, either with earmuffs or a tank. I can only assume that some of the old impeller has been pushed into the water passages in the motor.

Any good tricks to clear this out? Assuming the worst, i.e. I can't clear it, what is the next step?

tx,
bmc

Aurelia · Posted: Tue Mar 02, 2010 10:34 am Post subject:

Use compressed air from a can or compressor pumped into the outlet while the motor is running. Local Honda master tech recommended this and it worked for me last week on a 90.

bmacpiper · Posted: Tue Mar 02, 2010 3:55 pm Post subject:

Thanks Dan. Do you mean into the telltale? Wouldn't the water pressure from the pump just push the debris right back into the motor, or is it supposed to go all the way through and out the telltale?

tx,
bmc

Fairbro · Posted: Tue Mar 02, 2010 5:11 pm Post subject:

Along those same lines, I use heavy duty weed whip line to clear out the simple spider webs and algae clogs. I have to do it about every week here on the river. It is much easier to work with than wire in long lengths.

thataway · Posted: Tue Mar 02, 2010 6:46 pm Post subject:

To use compressed air (air compressor and you can vary the pressure), work back toward the impeller, with the lower unit off--and blowing into the lines from the head unit to push any debris out of the bottom (opposite the way water is pushed from the impellor).

rjmcnabb · Posted: Wed Mar 03, 2010 4:08 am Post subject:

I wonder if this backwards clearing stuff has anything to do with the side-mount flush hoses on Hondas (and, I think, Yammis?) Apparently, part of the reason not to run the engine when you flush that way is that the water stream is going through the impeller backwards. I got this from an OB guru at SG Sports in Victoria BC.
Rod

bmacpiper · Posted: Wed Mar 03, 2010 2:05 pm Post subject:

Hey Rod,
Not sure I follow you. Are you referring to earmuffs when you say "side mount flush hoses"? When using earmuffs or a tank, isn't the water coming in the normal way, i.e. bottom to top?

Fairbro--thanks for the weed whacker line tip--that's gold. I was wondering how I was going to access the channels in the motor. I almost think that could have benefits for knocking out salt too.

Thanks to all, I'll let you know what works.

tx,
bmc

DaveS · Posted: Wed Mar 03, 2010 2:39 pm Post subject:

Ben,
Last year one of my 50 HP Johnsons had a weak tell tale flow that I was unable to correct with the weed whacker line. While the engine was running, with a fine nozzle tip on my compressor hose, I placed the tip on the outlet and gave a quick blast of air into it and the partial obstruction was successfully cleared. (Basically, a quick back flush).

bmacpiper · Posted: Wed Mar 03, 2010 3:03 pm Post subject:

Thanks Dave. I'll give it a shot and see what happens. Simple solutions are always preferable...

tx,
bmc

rjmcnabb · Posted: Wed Mar 03, 2010 4:08 pm Post subject:

Hi bmc, (Newer?) Hondas (mine is 2007 EFI 90 hp) have a hose outside of the housing (starboard side, as I recall) with a garden hose-compatible screw-coupled link in the middle. Open the link and the FEmale side will accept the male fitting of a garden hose. Screw in the hose and turn on the water and you start to flush the engine. Don't run the engine because this method is forcing water backwards through the impeller on the cooling pump. A similar setup is used on Yammis; I don't seem to be able to find it, but one recent picture album had a Brat using a Y-valve to connect his garden hose to twin O/Bs and flush both at once. Earmuffs or a bucket have water going through the cooling system in the good, old-fashion direction. I hope this is clearer. Question

Ciao, Rod
Sorry for the typo.

bmacpiper · Posted: Wed Mar 03, 2010 4:18 pm Post subject:

Thanks Rod, that makes sense. My motors are both 2004, and the 90hp has a threaded fitting that accepts the garden hose adapter you mention. My dealer tells me that on my motor at least, the factory flush system is not very good compared to using muffs or a bucket, so I've never used it and hadn't considered which direction the water would be flowing.

I'm going out now to try the compressed air method, will report back.

tx,
bmc

bmacpiper · Posted: Wed Mar 03, 2010 6:04 pm Post subject:

I blew air backwards through the motor, and it bubbled in my bucket of water below. Also removed the lower unit, and could feel the air coming out the metal pickup tube that inserts into the rubber sleeve on the top of the water pump.

That's when I realized, "Hmmm, that tube moves around pretty freely. I wonder if it could have missed the pump..." So I tried to mount up the lower unit with the tube intentionally to the side of the pump, and sure enough, it went together slick as snot.

So, this turns out to be a likely I/O error (idiot operator).

I'm pretty sure I just had the metal pickup tube to the side. Installed it correctly, and voila, pressurized water out the telltale, even at idle.

Thanks for the tips, filing them away for future reference. Happily kicking again.

bmc