Air coming out the telltale engine cooling line instead of water

[bigtexan99]

My Sportster has the coolant water telltale line rerouted to the side of the hull so that I can check the output stream while underway. It started sputtering the last couple of times I took the boat out, instead of being a steady stream when underway. However last week it turned into mostly air coming out the line with just occasional spurts of very hot water while underway.

Other than this erratic water stream, the boat ran very well. I do have some cavitation when getting the boat on plane, but I just feather the throttle down when the impeller slips and am able to get up and going on plane.

What should I be looking at to resolve this water/air issue in the cooling system?

 

[noviceskier]

large gap in the wear ring clearance to the impeller will cause this, either that or system has been clogged with sand or other debris, but since you mentioned the cavitation I would look there first.

 

[bigtexan99]

I can pull the jetpump and take a look and the wear ring clearance.

Is there a way to flush the cooling lines or check for clogs?

 

[mikidymac]

What year is your Sportster? Some have a flush port at the back on the pump and some have a red connector at the back of the engine on the cooling hose.

 

[noviceskier]

I can pull the jetpump and take a look and the wear ring clearance.

Is there a way to flush the cooling lines or check for clogs?

you dont have to pull it, you should be able to see the gap when its sunny outside if there is one

 

[bigtexan99]

What year is your Sportster? Some have a flush port at the back on the pump and some have a red connector at the back of the engine on the cooling hose.

Its a 2003 with the 951 carb.

 

[gazzaskirepair]

Is it the Sportser Le
Where are flushing from, which connection
Where is the water exiting when flushing ?

 

[gazzaskirepair]

 

[bigtexan99]

Thanks for the diagram. Any tips on how to try and flush/check the system?

 

[gazzaskirepair]

Ok that diagram is for DI model
Confirm yours is a carb

 

[gazzaskirepair]

What happens during flushing on trailer ??
Where are you flushing from, which connection ?
Where are you getting water coming out from ?
Exhaust?
Jet Pump impeller area?
Alongside jet pump right hand side?

 

[gazzaskirepair]

 

[gazzaskirepair]

That’s the route the water takes during normal operation
It’s revered during flushing but only through the exhaust then the engine cylinders and out through the jet pump
It flows out the pisser tell tale during flushing then you have a low flow water supply from jet pump side meaning
Wear ring gap excessive = low pressure/flow to engine then exhaust
Restriction in jet pump area causing the same above
Blockage at cylinder head , just found the same type of endings with a blockage at elbow ITEM 10 in drawing above
So let us know where water is flowing out on trailer while flushing with hose ?

You can also remove the hose at elbow 10 and during flushing tell us if water comes out you will get water in the boat doing this but your looking for a steady stream coming out

 

[bigtexan99]

Thanks for the colored diagram! That makes understanding the flow so much easier.

I pulled the jet pump and lo and behold discovered a rock wedged in there. Had to chisel it out with a hammer and screwdriver. I'm hoping that was the issue with both the water flow and cavitation.



Since I was already there, I pulled the the hose off the engine inlet (by the cyclinders) and ran water through it, no issue it flowed out the main water intake at the jetpump.

The jetpump has that one tube with the 4 holes, I think thats the main intake. It was a little clogged with sediment (just a little), I flushed it out real good.

Pulled the hose of the big fat exhaust pipe and it flowed to the side mounted piss hole with no issues.

Going to lake test tomorrow.... if its still not a steady stream of water out the side mounted piss hole then I will focus on the exhaust portion that has the water regulator that looks like the RAVE cap.

 

[gazzaskirepair]

You can run it on the trailer with a hose pipe that helps in the trouble shooting but as you found a rock and water inlet partly blocked that should be your problem
Did you measure gap between impeller and wear ring ‍

 

[bigtexan99]

Got the sportster to the lake this morning and it was a disappointment. There is still just intermittent water out the side mounted piss hole (that is fed off the top of the fat exhaust #7 in above picture.). The amount of cavitation was slightly decreased.

I didnt measure the gap in the wear ring, but its pretty tight.

I just don't understand where all this air is coming from. Is it the exhaust regulator (that looks like a RAVE cap).

 

[noviceskier]

dont know if this is the same but did you replace the neoprene seal when removing and reinstalling the jetpump?

 

[bigtexan99]

Good idea, but the 2003 sportster does not use the neoprene seal. It has a reusable gasket thing. At least that's my understanding of it.

 

[gazzaskirepair]

Do the trouble shooting on trailer at home by running it on a garden hose pipe

 

[bigtexan99]

I connected the hose, started the engine, and turned on the water. The only water that came out was just to the left of the jet pump, out the exhaust. Nothing came out of the piss holes at the back of the boat or the sidemounted piss hole.

After a couple of minutes the engine got to hot so I had to stop testing.

 

[gazzaskirepair]

You have a blockage
Anything come out the jet pump at the impeller area 11 o clock looking forward from the back

 

[gazzaskirepair]

Confirm you connected hose at the fitting next to engine compartment

 

[gazzaskirepair]

 

[gazzaskirepair]

You connected to the connector in red ‍
It’s better to connect the hose at fittiing to the right of the jet pump
You can use a 3/4 hose fitting , quick release type is the easiest
But have connector on left of engine compartment closed

 

[bigtexan99]

You have a blockage
Anything come out the jet pump at the impeller area 11 o clock looking forward from the back

I didn't notice anything at 11oclock position. There was exhaust smoke and water coming out about the 9 oclock position.