Water Pump - Honda 15

TyBoo

TyBoo

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Staff member
OK, I need some ideas. My 2000 Honda 15 has no water from the telltale hole. It was that way when I first got it, then after a flushing and desalting it worked fine for a short while. Now it is back to no stream.

I just now removed the lower unit and looked at the impeller. It looks to be in great shape. It has a pretty good set, but the rubber is intact and supple. There is no sign of abrasion at all, and the pump liner sleeve is smooth and clean. The key is in place. Obviously (to me, anyway), the water pump itself is not the culprit. If they have a new one in stock at the Honda shop across the river, I will replace the impeller since I have it apart, but I don't think it will solve the problem.

I can blow through the telltale fitting and the hose, albeit not a great volume. Blowing through the tube from the pump to the engine is unrestricted, and there is no blockage or foreign material in the pickup screens or the pump housing and ports.

So? Thermostat? Wouldn't it allow flow through the telltale whether the thermo is open or closed?

Any help will be appreciated. I'm a millwright, not a durn marine mechanic!

Thanks.
 
Hi Mike,

Here's my best guess from afar...

I think your flushing and desalting routine probably just knocked some scale or salt loose from the passages and you're getting some blockage.

When you're running the engine on a hose are you getting water out of the end of the prop? And some "spitting" out of the exhaust bypass opening at the top of the extension housing (the piece the lower unit is actually bolted to)? With the hood off and the engine running and not peeing can you still touch the engine?

If you have compressed air available you can GENTLY blow back through the tattletale hose while the engine is running...DON'T use everything you've got if your PSI is set up around 120 or so. You're just trying to dislodge anything that's managed to get itself jammed. Just take the end of the hose of the little plastic fitting in the case and stick your air chuck in the end of the hose.

You're right about the thermostat; the tattletale water doesn't come through there on a Honda. It should be checked to make sure it's not stuck but just because you should, not because it's affecting the pee stream.
 
Thanks, Les. I think she's gonna be just fine. The plastic nozzel for the stream had some crud in it. I took it out completely (kinda slick how the lock tangs for the fitting pinch the hose onto the nipple) and could barly see daylight through it. Then I blew some compressed air through the thing, and it opened right up.

I went over to your associate's shop and got a new impeller to stick in since it was apart anyway. I layed the vanes over the right direction and put a little grease on them just like you showed me.

Looking at how the flushing port is plumbed right into the pump housing, I could use only it to run the motor in the driveway, huh? I'll give it a try when I pull it out from the shed before launching. I will be very careful to not lose the screw this time.

I haven't tried it yet, but I am confident it's all better.

Since the shifter rod goes up and down in the 15, rather than rotate like the 75, I take it you unscrew the rod coupling in the middle to get the lower unit off? That's what I did, using the locknut as a gauge for readjustment.

Now it is on to other tasks..........
 
De-bugging the tell-tale cooling stream is a nearly annual occurence around here in the warm Central Valley of California. It seems insects love he little hole to hide in. Often it's caused by a small wasp that's stuffed another stung and paralyzed bug into the hole, and then subsequently laid an egg inside the bug's body with her stinger/ovipositor. The egg hatches a little later and the young wasp larva parasitizes the body of the other bug, then pupates and subsequently emerges as an adult and flies away, leaving a dead insect exoskeleton and a pupal case in our little ""pee-pee" hole"! (Glad it's the motor and not me!!!). Scared me the first time the motor wouldn't do it's duty, but now I'm accustomed to finding the passage blocked and keep a straightened out hook with the barb cut off ready at hand with which to poke around in the hole and break it open. Joe
 
Hey Les, while I'm thinking abut it, Tybo mentions coating the impeller with grease to help seat and lubricate it. How about using a synthetic silicone grease like the clear "Super Lube" stuff? We used in in science lab work with vacuum work for years before it became generally comercially available because it has no vapor pressure, e.g., it doesn't vaporize or send any molecules off into the air and therefore doesn't dry out and get old. I used it to lubricate the stainless and neoprene parts of suction bailers on sailboats for years, and put it on the impeller in an old 18 horse Johnson when I reassembled it after changing the worn out clutch dogs. Any thoughts? Joe.
 
Hi all,

When I was working in the outboard shop, we used 2cycle oil(the kind that you mix in the gas) to lube the impellers. The oil is formulated to not affect the rubber in fuel hoses or carburators, so it shouldn't bother the impeller.

After the outboard with the new impeller is used in the water the oil or grease is washed off, and its the water that lubes the rubber.

Never start an outboard 'dry', the impeller will burn in seconds.
 
Hi Sea Wolf,

Geez, I've become such a paper-pusher that I've hardly spent any time in the shop lately. We use a white grease (that's what I was trying to remember the name of) to lube the impeller; it's really just to give us a way to get the vanes to spin the right direction as the stainless housing is placed over them. When they're dry they really stick and trying to get it all back together is not fun.

It doesn't last long once the engine starts; as Larry says it washes away very soon.
 
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