2000 Johnson 15hp wont pump water

[Richid]

I just got a 15hp Johnson it starts up runs great pumped water on muffs but not in the lake. Changed water impeller old one was missing fins so I thought that was the problem. Still not pissing out of tell tale in lake only on muffs

 

[909]

Check if your tell tale hose is clogged. If not :

Likely improper assembly / missing key

Or Bad vermitherm / thermostat assembly ( cup commonly deforms from high temps )

Or crap is just stuck in there, likely your old impeller fins + lake debris

You're using OEM parts I hope . Aftermarket impellers simply don't pump enough water most of the time

 

[tphoyt]

Agreed if it was missing fins they are properly jammed up somewhere.
The hose pressure may have been enough to push water to the pisser.

 

[Richid]

So if I take the lower unit back off and blow air through the telltale could this possibly clean and debris out? I’m pretty new to working on outboards I literally have to since nobody around me will touch a Johnson for some reason

 

[tphoyt]

If you were getting water out of the tell tail while on the hose it’s not likely that’s where the problem lies. The tell tail passages don’t circulate through all the water passages. First check to be sure the pump service was done properly and the key is in place. If you wanted you could drop the lower in a barrel while it’s off and spin the shaft with a drill to be sure it’s pumping.
Water level must be well above the pump.
You could also try a shop vac on the water tube to try and pull debris back out. Use a clean vac so you can check it to see if you were able to get anything out. Other than that your looking at pulling the head and cleaning the passages. You could check the thermostat first to see if that’s were the obstruction is.
I don’t want to lead you down the wrong path others may have better info but this is what I would looking to do if blockage was suspected.

 

[Richid]

I see a lot of water coming out around the water pump housing it doesn’t look right to me? there Was no gasket there when I took it apart and the pump kit didn’t come with one. Am I supposed to us some kind of marine gasket sealer there?

 

[909]

No sealer req'd

Did you know have a flushing port ,

but I think likely it's a bad install,

or a bad thermostat assembly.

You CAN remove the thermostat all together to eliminate a possible point of failure .

 

[Richid]

Thanks for all the ideas but still not pumping water. I have exhaust coming out of the telltale. Already changed head gasket and checked exhaust gasket. What else could it possibly be? Motor runs great I am lost

 

[tphoyt]

What did you mean by your seeing a lot of water coming out around the pump housing?
Did you have the lower off and were testing with a drill in a bucket when you saw this?
Do you recall what the rest of the pump looked like when you changed the impeller? Was the wear plate and cup if it has one in good condition or were there groves worn into them?

 

[Richid]

Yes I was testing with a drill. It was the new water pump housing that did not have a good seal. Re installed old one and was fine. Motor is at a marine shop now and they installed another new water pump, checked for blockage, did the exhaust and head gasket, I was told pump is working just not getting through the engine and exhaust is coming out of the telltale

 

[clemsonfor]

If exhaust is coming out of the telltale you have a blown head gasket. It's mixing exhaust into the cooling passages. Maybe they used an incorrect gasket, didn't torque it right. I have no clue? Before this I would have said I bet you might have a stuck or defective thermostat.

Does the head get hot while running on the muffs? I suspect like others the water out the telltale on the muffs is just from your house pressure.

 

[tphoyt]

Best of luck. I hope they get you up and running soon. I wouldn’t be surprised if they find the fins of the old impeller you mentioned were missing causing some blockage.
Keep us posted.
Best

 

[racerone]

When testing in a bucket water must be 6" above the impeller.

 

[Richid]

I just got my motor back still not fixed. The guy went through the whole motor several times from the foot all the way up checked for blockage, changed gaskets. Pumps some water for a few minutes now then stops. Does this with and without thermostat installed

 

[saltchuckmatt]

I just got my motor back still not fixed. The guy went through the whole motor several times from the foot all the way up checked for blockage, changed gaskets. Pumps some water for a few minutes now then stops. Does this with and without thermostat installed

The only other thing it could be is the draw tube has a hole in it or the grommet at the top has failed. Powerhead would have to come off to verify unless someone else has a trick that I don't know of.

 

[flyingscott]

Or the key is not in the impeller.

 

[oldboat1]

Work a piece of weed whacker line into the tell tale to try to clear it. Main issue, though, is overheating (160F or more at the top of the cylinder head). Has it overheated?

You can try to clear a blockage in the water passages by pulling the lower unit and pushing hose water up the tube -- should exit from the leg.

 

[Richid]

Motor has been completely ripped apart and put back together and flushed out not a chance of blockage. It does pump at times

 

[saltchuckmatt]

Motor has been completely ripped apart and put back together and flushed out not a chance of blockage. It does pump at times

Ask your repair guys if the pulled the powerhead from the mid-section...nobody would if they thought the draw tube was okay. It really can't be anything else other than a crack somewhere and it would be burning water or leaking it. That's my 2 cents

 

[oldboat1]

Is the block too hot? tell-tale aside, water is circulating properly if the engine is operating at normal temps (130-140F on the top of the head). 150F or too hot to touch is too hot to run. I haven't checked, but I think the tell tale hose comes off the exhaust cover, about half way down. Take off the exhaust cover and clear any blockages.