No Water Flow - Yamaha Sterndrive L4

[mtsumedi]

Brand new impeller. Flows a little bit of water on the round earmuffs. Dropped it off into the lake and the raw water pumped moved no water whatsoever. I took the inlet hose off from the bottom of the raw water pump, cupped my hands over the end, and blew air through it and I could hear the bubbles outside of the boat in the back and then the water coming back up the hose but not far enough to even be seen.

What could the possible cause of this be?

 

[Bondo]

Re: No Water Flow - Yamaha Sterndrive L4

Ayuh,.... So you replaced the impeller,... What did it's Housing look like,..??

Any scratches or scrapes won't allow the impeller to work...

 

[ricovw]

Re: No Water Flow - Yamaha Sterndrive L4

Did you locate the broken impeller pieces? Also, there is the sea water pump( with the rubber impeller you replaced), and there is also the circulation pump. It is belt driven on the motor. I'd check that also.
If you do need the circulation pump, let me know. I'll look up the crossover part. There is an automotive equivalent for 60 bucks, as opposed to struggling to find a used yammie one for several hundred!

 

[mtsumedi]

Re: No Water Flow - Yamaha Sterndrive L4

The housing appeared fine. I need to do Capt Ken's air test on it.

I got as much of the impeller out as I could. The problem is with the water actually getting to the raw water pump so I don't think impeller pieces is the issue.

I'm thinking my issue is in the leg. Sometime in the past the motor got really hot and melted out the rubber on the flap on the down pipe. When I had the outdrive split I noticed some melted plastic where the brass water tube should have been so I'm assuming it got very hot down there as well to cause this. I will resplit the outdrive and see what I can find.

 

[Capt Ken]

Re: No Water Flow - Yamaha Sterndrive L4

The hot exhaust wll melt the plastic guide tube but rarely gets the rubber grommet. One problem we see is the plastic tube that comes through the transom. It will split some times and cause the pump to suck air but usually sitting still in the water, it will still suck enough to stay cool. Don't use any automotive parts on the cooling system. They are not corrosive resistant and will not last long. Do the blow test on the pump and see how tight the internals are before you get too far. Also remove the water hose going to the exhaust manifold and blow through it to see if there is any resistance. You many have a riser stopping up.

 

[mtsumedi]

Re: No Water Flow - Yamaha Sterndrive L4

Blocking one end of the pump and blowing it does not allow air through on either side.

Blowing straight through shows some resistance but not a ton. I can feel a slight breeze out of the other end but not a gush of air when I do so.

What if I stuck the other end of the pickup hose that mounts to the transom into a bucket of water and started it up? Would it pull water then if the pump was working correctly?

Here are some pictures:

 

[Capt Ken]

Re: No Water Flow - Yamaha Sterndrive L4

Why is the pump shaft not in the center of the wear plate hole?

 

[mtsumedi]

Re: No Water Flow - Yamaha Sterndrive L4

Why is the pump shaft not in the center of the wear plate hole?

The angle at which I took the picture. :joyous:

 

[55evinrude]

Re: No Water Flow - Yamaha Sterndrive L4

like everyone has already stated check all hoses going to the thermostat and circulating pump for any debris. why does the impeller housing look all deformed around the around the edge inside, I doubt that would effect anything but you never know.

 

[mtsumedi]

Re: No Water Flow - Yamaha Sterndrive L4

I'll do some testing tomorrow and split the drives to see what I can find.

Cap'n Ken, do you carry any of the water tube guides/seals in stock? BTW, I'll be in PCB March 13-17 so I may swing in to meet you.

 

[mtsumedi]

Re: No Water Flow - Yamaha Sterndrive L4

I didn't get around to splitting the drive but here's what I did do:

I took the water line that connects to the transom, unhooked it and stuck it in a bucket of water. Started the engine and got absolutely no suction. I even submerged it and lifted it a few times to push water down to the raw water pump in hopes of priming it. No luck.

I then took the same line and stuffed the garden hose into it and water ran through the system.

Does this mean the $600 raw water pump is bad?

 

[Capt Ken]

Re: No Water Flow - Yamaha Sterndrive L4

Possible but not probable. Was there any back pressure on the garden hose when you forced water through the pump? Remove the outlet hose from the pump and connect your hose there and see if there is any back pressure. I'm wondering if the manifold and riser is plugged up and not allowing water to flow through. Being you are on the coast of Ms, this thing has probably seen its share of salt water. As for the $600 pump, last time I looked they weren't available anymore.

 

[Capt Ken]

Re: No Water Flow - Yamaha Sterndrive L4

I was incorrect, there is no pumps in the states but I show 3 in Japan. $805

 

[mtsumedi]

Re: No Water Flow - Yamaha Sterndrive L4

How about the thickness of that O-ring. I was reading on some other forums about raw water pumps in general and saw where that was an issue for some guy. I also read about trying to smooth everything out in there as well. My cam appears to be in good not worn down shape so I will play around a little and see what I can come up with.

Thanks for your helps so far.

I actually live in Jackson, MS area and the boat was purchased in Columbus, MS and then kept in Grenada Lake. Not a lot of corrosion that I can see.

 

[mtsumedi]

Re: No Water Flow - Yamaha Sterndrive L4

Oh, I also took the manifold off yesterday and am going to go through it as much as possible. The last person who put it together did not put an exhaust/intake manifold gasket on it.

 

[mtsumedi]

Re: No Water Flow - Yamaha Sterndrive L4

Problem was.......

Drum roll please.

thick @$$ o-ring.

I took the o-ring off and put some gasket maker on there and put it back together. Pumping water fine now.