95 WaveRaider 700 cooling

[bmclaws]

My ski has two hoses the come through the rear bulkhead into the engine compartment. One, the 1/2" hose is disconnected and plugged. The other hose, 3/8" dia, goes into a T and splits off to a couple of places on the aftermarket Coffman exhaust.

The flush line is tapped into a line running into the back of the block/head. When flusing, the water-jacketed Coffman exhaust is cool, the engine/heads are cool, and water comes out of the side vent toward the front of the ski and out of the exhaust.

In the water, the exhaust is very warm, as is the block and head. No water that I can see is coming out of the side vent.

How much water should be being fed to the engine/exhaust when the ski is in the water? Is the 3/8" hose enough, or should that capped off 1/2" hose be used?

[jvdsuperjet12]

Re: 95 WaveRaider 700 cooling

a bigger hose would never hurt ya know. but there ciould be a leak somewhere if there is no water coming out the pisser

[Antwon]

Re: 95 WaveRaider 700 cooling

Too much cool water rushing around your engine is just as bad as not enough water rushing around your engine.

[David3aces]

Re: 95 WaveRaider 700 cooling

1/2 inch line is the old exit line...3/8 line is feed line...yamaha would connect feed line to exhaust manifold first which would then flow into cylinder up and out of cylinder head (front) and into curved part of exhaust which would flow up pipe and out top of pipe to exit line. A t would be in the line between head and curved pipe for water pee line...

Your coffman pipe has a t in the line coming from the jet pump before the engine? You have no flow when ski is in the water? If so I would remove these lines and make sure they are clear...I have seen clogs that would not blow out with compressed air..I had to beat the hose on concrete to get the compacted sand out of the hose...so remove and check hoses if no flow.

[bmclaws]

Re: 95 WaveRaider 700 cooling

Thanks for the replies....

The way this Coffman pipe is set up is this:

3/8" line coming through bulkhead comes to a 'T'.

One side of the 'T' goes to the bottom of the exhaust pipe.
The other side of the 'T' goes to another 'T'.
Each side of the second 'T' goes up to the exhaust manifold right where it bolts to the block.

From the first 'T' that goes to the bottom of the exhaust, water travels through the exhaust pipe water jacket and goes exits up about 8" into a line that goes to the rear of the block/cylinder head. There is a 'T' in this line that goes to the flush hose.

A line comes off the top front of the head and exits through the pisser.

Finally, a jumper line crosses over a 5" exhast hose that ties the two halves of the exhaust together (at the very top), and another line comes off the downstream half and dumps into the tail cone.

I'm assuming that the water from the two lines entering where the exhaust bolts to the block is the water traveling up to the crossover and the line entering the bottom of the exhaust is the one coming out and going to the back of the block.

When flushing, everything runs cool to the touch. When on the water, everything is very warm although it isn't hot enough to burn.

I'll check the inlet hose for clogs.

One last question... is there a pump that pumps the water to the engine compartment or is it done by the force of the jet?

Thanks again for your help...

[bmclaws]

Re: 95 WaveRaider 700 cooling

I've been looking over the cooling line arrangement in my ski. The supply line comes from what I assume is the high pressure side (downstream of the impeller) of the jet.

I'm wondering what type of flow rate I should be expecting. I'm also a bit concerned that with the aftermarket exhaust and all the Tees installed, there may not be enough flow.

Here's how it's set up (please forgive the crude drawing):

Supply Line --------------- TEE --------------------------------|
| |
| |
| Exhaust Manifold
----------- TEE -------- Lower Elbow
| | Water Jacket
| | |
| | |
Exhaust Manifold Exhaust Manifold |
Water Jacket Water Jacket ----- TEE -----
At Block At Block | |
| | | |
|-- Exh Man Wtr Jck --- | To Engine Flush
| | Conn
| |
Exhaust Tail Hull Pisser
Cone

All lines are 3/8". The problem is that in the water everything is very warm (not quite burning hot, but uncomfortably warm) and not much of anything flows out the pisser. However, on the hose everything is cool to the touch and water shoots several feet out the pisser.

There doesn't appear to be any blockages as the hoses flow fine. How cool should the engine/exhaust be running in the water? Cool to touch as on the the hose? How much water normally flows out the pisser while scooting along in the water?

[bmclaws]

Re: 95 WaveRaider 700 cooling

Well, that drawing attempt looks nothing like the way it appreared in the Edit window... all the spaces were removed....

Here's a crude .jpg of the setup...