New Owner, have questions

[ranger305]

I've been a boater and shade tree mechanic for years maintaining and repairing my own gear, mostly OMC outboards, Mercruiser sterndrives, etc. Last week I entered the world of PWC's and picked up a 1996 GTX with the 787 engine. This ski had been sitting in a garage for 10-12 years with a factory cover on it. Best I can tell from the gauge, needs new polarizing piece, the ski has 156 hours on it. After dragging it home and doing a visual inspection, I pulled the plugs and dumped some seafoam in the cylinders for 24 hours to lube things. I drained the fuel, put in all new fuel lines, checked compression (was ~125-130 cold, before starting, on my cheap HF gauge) and cleaned/rebuilt both carbs with true Mikuni kits. Installed a new battery, poured in some fresh non-ethanol fuel, added oil to the tank (had a bit in it) and it fired up in short order and seems to idle/run well. Discovered that one of the welch plugs in the head pipe has a crack, so I threw a wrap of tape on it so I could head to the water to test it. Also have picked up the stuff for a drive oil change.

On the water, it had heavy 2-stroke smoke for the first 3-5min, then got to what I would call normal. Ran it conservatively for a bit, eventually racking up an hour or two of run time. I did a couple full throttle runs after a while of break-in and getting familiar with the ski. The info center registered 55mph, so I'm guessing it was really maybe 50. Given that speed, I'm thinking the engine is running well on the top end.
Here is what I have come up with so far-

1- Ski seems sluggish until about 3000 rpm, then, right before it comes on plane, can suddenly accelerate very hard. I expect this to a degree, but the difference is VERY apparent. It's almost like it switches from low speed jets to high speed. It runs well at the lower RPM, but I'm not sure if there should be more power there, or if this is the nature of the beast. It seemed to make no major difference if there was one adult or two on board, it was about the same feel.

2- Should I clean the RAVE valves out or do some kind of maintenance to them?

3- Has anyone tried using the propane torch melt aluminum welding rods on these exhaust plugs? I have the pipe out and cleaned, ready to fix, but finding a tig welder isn't likely to happen for a while. I've searched, but haven't seen where anyone tried this, but I'm sure it's been done before.

4- The gas gauge isn't working. Can I release the tank straps, remove the 4 fuel lines, and just slide the tank forward to get access to the sender?

5- While in changing the pump oil, anything else should I check?

6- Reinstalling the head pipe, is copper Permatex RTV good to use for the flanges where the circle clamp goes, or should I use Loctite 518?

7- The oil lines are the same grey as the old fuel lines. Should I change them as well?

Sorry for all the questions. Looking forward to

 

[Coastiejoe]

Most do replace the oil lines as the get old and brittle. Most also replace the fuel selector as it gets plugged or sucks air at the shaft. Gas gauge is normally just a magnet issue, BRP has an updated magnet that is a different color than the original.

When changing the oil, check out the impeller bearings well as it will be in your hand.

Since you are that deep, if it were mine I would pull the drive shaft and replace the Carbon Seal (I think you have a CS not the Carrier Bearing style).

The plugs on the exhaust fail all the time. The proper repair is grind them clean and weld them. Once it is pulled, do all the bottom plugs even if they are not leaking,,, as they will leak...

Cleaning the Rave valves is always a good thing to do.

 

[digital sol]

1- Ski seems sluggish until about 3000 rpm, then, right before it comes on plane, can suddenly accelerate very hard. I expect this to a degree, but the difference is VERY apparent. It's almost like it switches from low speed jets to high speed. It runs well at the lower RPM, but I'm not sure if there should be more power there, or if this is the nature of the beast. It seemed to make no major difference if there was one adult or two on board, it was about the same feel.

2- Should I clean the RAVE valves out or do some kind of maintenance to them?

Yes, pull them out & check the orings & bellows for leaks or tears. Clean the valves "I used degreaser and a soft brush". You can also check the housing for wear & tear, the manual shows clearance specs there.

3- Has anyone tried using the propane torch melt aluminum welding rods on these exhaust plugs? I have the pipe out and cleaned, ready to fix, but finding a tig welder isn't likely to happen for a while. I've searched, but haven't seen where anyone tried this, but I'm sure it's been done before.

Not sure

4- The gas gauge isn't working. Can I release the tank straps, remove the 4 fuel lines, and just slide the tank forward to get access to the sender?
You can remove the center counsil & pull the fuel sender from there without removing the tank but keep in mind sometimes the magnets on the float come off and sink to the bottom of the fuel tank.

5- While in changing the pump oil, anything else should I check?

6- Reinstalling the head pipe, is copper Permatex RTV good to use for the flanges where the circle clamp goes, or should I use Loctite 518?
I used red high temp RTV sealer *Make sure its ok to use with gasoline*

7- The oil lines are the same grey as the old fuel lines. Should I change them as well?
Yes change them all while you are at it

Replied ;;;;;;;;;;;

 

[soccerdad]

I've been a boater and shade tree mechanic for years maintaining and repairing my own gear, mostly OMC outboards, Mercruiser sterndrives, etc. Last week I entered the world of PWC's and picked up a 1996 GTX with the 787 engine. This ski had been sitting in a garage for 10-12 years with a factory cover on it. Best I can tell from the gauge, needs new polarizing piece, the ski has 156 hours on it. After dragging it home and doing a visual inspection, I pulled the plugs and dumped some seafoam in the cylinders for 24 hours to lube things. I drained the fuel, put in all new fuel lines, checked compression (was ~125-130 cold, before starting, on my cheap HF gauge) and cleaned/rebuilt both carbs with true Mikuni kits. Installed a new battery, poured in some fresh non-ethanol fuel, added oil to the tank (had a bit in it) and it fired up in short order and seems to idle/run well. Discovered that one of the welch plugs in the head pipe has a crack, so I threw a wrap of tape on it so I could head to the water to test it. Also have picked up the stuff for a drive oil change.

On the water, it had heavy 2-stroke smoke for the first 3-5min, then got to what I would call normal. Ran it conservatively for a bit, eventually racking up an hour or two of run time. I did a couple full throttle runs after a while of break-in and getting familiar with the ski. The info center registered 55mph, so I'm guessing it was really maybe 50. Given that speed, I'm thinking the engine is running well on the top end.
Here is what I have come up with so far-

1- Ski seems sluggish until about 3000 rpm, then, right before it comes on plane, can suddenly accelerate very hard. I expect this to a degree, but the difference is VERY apparent. It's almost like it switches from low speed jets to high speed. It runs well at the lower RPM, but I'm not sure if there should be more power there, or if this is the nature of the beast. It seemed to make no major difference if there was one adult or two on board, it was about the same feel. You may try pulling the choke slightly when you accelerate to see if it is a little lean. You may just be off a little with the LS setting on the carb. But it may just be the rave valves kicking in. These skis hit pretty hard when they come on the pipe and the raves open. So that may be what you are feeling.

2- Should I clean the RAVE valves out or do some kind of maintenance to them? Yep, just take them out and clean them up. Replace the gaskets and orings if they are bad or the orings are rock hard.



Sorry for all the questions. Looking forward to

Welcome. Great ski. The oil smoke was probably just some crank seal leakage from sitting. I have some gauge film available if you want to replace it. $10 shipped. Just PM me.

 

[FaceDeAce]

The power jump you feel is nature of the beastie 787 when it goes "onto the pipe". The transition can be adjusted and tuned (barely sort of) by the spring pressure of the rave valves AND the waterbox water to pipe regulator. Just get used to riding up on the pipe - its alot more fun!!!!

 

[ranger305]

Thanks for all the info, I have a lot to learn, lol. Ordered a new float and gauge fix kit yesterday and will clean the Rave valves and do the drive oil in the next few days. Any work on the crank seal may be a winter project. Not sure what might be involved there. Is the re a write-up or something on re-priming the oil lines after replacing them?

 

[ryffish]

as far as your exhaust plugs leaking what is different was grind off the existing rotten part and aluma welded a aluminium slug over it worked like a charm

 

[jammin777]

yes replace those grey tempo fuel hoses!