Is it the WATER PUMP? HELP!!!!!

[next boat]

I have a 4.3 liter V6 yamaha sterndrive. I know now that these are not the most convenient engines to work on, due to the lack of part dealers etc...here's the deal.

I have used the boat 4-5 times this year, I just bought it a month ago, and it ran fine. On my last trip out, the engine was running hot, so I pulled her out, and assumed I needed a new impeller. I found out that the impeller is inside of a belt driven pump on the engine itself, not the outdrive. I pulled the old impeller out and it was FRIED! I replaced the impeller and dug out all the fins in the exhaust hose, etc. When I hooked everything back up, I got no water still. I reverse flushed all lines, got all the rubber pieces I can find out. I disconnected the hose from the transom bracket, and ran the intake hose into a bucket of water, turned it on and it sucked the water beautifully, then just stopped....now it wont pull anything!!!! I have spoken to a few people, and they say the pump should be replaced every 4 years. Is that true? What am I missing??? I am frustrated, and need advice (besides get rid of the yamaha IB/OB) Is there a way I can test the pump before I spend the 350.00 to replace it. Thanks.

 

[Dakota47]

Re: Is it the WATER PUMP? HELP!!!!!

Make sure new o-rings were used. and gaskets.. needs a good seal...

 

[Muqwump]

Re: Is it the WATER PUMP? HELP!!!!!

Have you checked the outdrive?

 

[next boat]

Re: Is it the WATER PUMP? HELP!!!!!

The impeller came with an o-ring, and a paper gasket. I put those on. and I checked the outdrive hose for leaks, found none. There is nothing in the outdrive that pushes the water, so I dont know what else I can check. The pump has to pull the water 5-6 feet. poor design I believe.

 

[Coors]

Re: Is it the WATER PUMP? HELP!!!!!

A pump would rather suck air, than the heavier water.
Check the hose.

 

[bomar76]

Re: Is it the WATER PUMP? HELP!!!!!

The pump has to pull the water 5-6 feet. poor design I believe.

Not at all...
That is the best design, and as long as you don't have some upstream problem they work exceptionally well.

 

[Bondo Again]

Re: Is it the WATER PUMP? HELP!!!!!

The pump has to pull the water 5-6 feet. poor design I believe.

Ayuh,....

Actually,... when the boat is sitting at rest in the Water,.....
The Pump is in a Flooded state, Below the Waterline.......

You could always mount a seacock right At the pump housing if you want....

 

[Don S]

Re: Is it the WATER PUMP? HELP!!!!!

I have a 4.3 liter V6 yamaha sterndrive.

I've been working on boats for about, uhhhhh, lets say over 20 years now, and I have never seen a Yamaha sterndrive. An engine mounted raw water pump that pulls 5 or 6 feet is so common in straght inboards that it's not even an issue.
Get yourself an OEM service manual (if you can find one) and fix the cooling system so it doesn't have air leaks, and it will work. You have to have tight air leak proof seals on hoses and fittings all the way to the water pickup.
Check the clamps, check any fittings and hoses in between.

 

[next boat]

Re: Is it the WATER PUMP? HELP!!!!!

Yeah. I have never seen a yamaha sterndrive either. The local yamaha outboard shop says they made them for like 4 years, and then they disappeared. I thought about putting a seacock right at the pump if there was a problem with the line to the outdrive, but I dont believe that is the issue. I am still wondering if I can test the pump somehow to know if it needs to be replaced. I will post a pic of it tomorrow, and maybe something will look funny to you guys. Have you all ever had to replace a water pump because of age, etc.... If I pour water in the intake of the pump, it leaks out the exhaust. Should it be a tight enough seal to block the water??? thanks.