97 gtx noise and maybe lack of power

[foulmouthfool]

97 gtx lack of powe r*updated*

what I've done to it since I got it:

replaced all old grey fuel lines
cleaned rave valves
replaced valve cap and bellows on one of the rave valves
bought a rectifier (thats right, bought, its still sitting on my work bench) speaking of, where exactly is it I don't even see it in the diagrams in my service manual.
replaced spark plugs
cleaned carbs and filters. I did not rebuild the carbs as everything but the filters looked pristine.


Riding yesterday I noticed a few things. I don't seem to have any cavitation issue like I posted about earlier, but:

1. midrange cruising seems iffy. it just doesn't run as smooth (sound wise) in the 4k range as I suppose it should. idles fine and really pulls hard from 5k to 6400.

2. if I put the ski in a "bind" as in starting off doing slow speed 360's, rpm's will not go over low 4k's like its struggling. As soon as I straighten it out it revs up and pulls hard. Is it normally underpowered like this?

3. After a few WOT runs I instantly let off the gas and as it slowed and idled down I could hear what I could only describe as rocks rolling around in a paint can. I couldn't pinpoint the sound to my engine or impeller area. If I started slowing down just a little before letting off the throttle it never made that noise. Out of the water I rev'd it high and letoff and never heard the sound but I did not hit WOT rpm's and stay there either.

 

[jhjesse]

what I've done to it since I got it:

replaced all old grey fuel lines
cleaned rave valves
replaced valve cap and bellows on one of the rave valves
bought a rectifier (thats right, bought, its still sitting on my work bench) speaking of, where exactly is it I don't even see it in the diagrams in my service manual.
replaced spark plugs
cleaned carbs and filters. I did not rebuild the carbs as everything but the filters looked pristine.


Riding yesterday I noticed a few things. I don't seem to have any cavitation issue like I posted about earlier, but:

1. midrange cruising seems iffy. it just doesn't run as smooth (sound wise) in the 4k range as I suppose it should. idles fine and really pulls hard from 5k to 6400.

2. if I put the ski in a "bind" as in starting off doing slow speed 360's, rpm's will not go over low 4k's like its struggling. As soon as I straighten it out it revs up and pulls hard. Is it normally underpowered like this?

3. After a few WOT runs I instantly let off the gas and as it slowed and idled down I could hear what I could only describe as rocks rolling around in a paint can. I couldn't pinpoint the sound to my engine or impeller area. If I started slowing down just a little before letting off the throttle it never made that noise. Out of the water I rev'd it high and letoff and never heard the sound but I did not hit WOT rpm's and stay there either.

1&2. Rebuild carbs and replace the N/S. Set HSA and LSA to factory. Use old springs on N/S to maintain correct pop off pressure.

3. Sounds like pump rattle to me. In the water the pump and engine are loaded. Out of the water there is no load.

 

[Dr Honda]

1) Hard to say, but could need a carb rebuild... but I would check for loose, or broken engine mounts.

2) Can be normal. Some skis in a full turn... starting from idle, won't break 5000 RPM's because of the pressure in the pump. You could adjust the spring tension in the RAVE's. Try screwing them in the entire way, and see if it get's better. If the RAVE's open prematurely... you will loose mid torque.

3) As above... it's probably pump rattle. (not an issue)

 

[foulmouthfool]

I don't think I am going to rebuild the carbs, they looked too good when I broke them down and I had the absolute hardest time getting them back on the intake. I was ready to take a sawsall to my hull then jb weld it back together

I've got to be honest with you, they way it runs in the mid range may be normal. It feels normal I would guess, but sounds like it might have a miss. I don't know at what RPM that normal 2 stroke sound is supposed to get smoother.....if that makes any sense at all to you guys.

I did take my rave valves back apart to make sure they were screwed all they way in (you do mean the actual red cap, right?) and noticed that the springs were different. The PTO side was weaker but I happened to have a spring that matched the MAG side and put that one in. Haven't run it again yet.

That puts my mind to rest about the ski not revving out in a full steer bind like that.

50/50 on glad sad about the noise. I figured it was nothing as it sounded similar to the pump rattle when the engine is started then killed out of the water. Glad that I don't have to be worried, and sad that its not about to blow up to prompt me to get something with a little more HP

 

[ski-d00]

everything sounds normal to me. the 787 has sort of a flat spot in mid throttle under load, then jumps to high power once the revs get a little higher. and sounds like pump knock.

 

[foulmouthfool]

Well I found out there was an issue. I took it out memorial day and my bud took his boat so we could pull the kids around. It seemed to REALLY struggle to get up to high rpm like I was dragging an anchor and it seemed to get progressively worse and started dieing on me for seemingly no reason. When you did get it up to high rpm, like hitting a wave and getting the intake out of the water it would take off like a raped ape. My friend took it for a spin (he had never ridden one) and when he got back he said "man I have to have one of these! But yours doesn't seem to run right" DANG, even someone never on one could tell there was an issue.

I was about ready to tear down the carbs again when I decided to see if my rave valves just gummed up that quick. They hadn't, but when I put them back together I realized that I have two different caps. The cap on the PTO side, when screwed all the way down won't allow the valve to move. Its basically stuck open. So I backed it off enough to let the valve move up and down as much as I thought the other one was, but I just eyeballed it. Put it in the water and ran 3/4 of tank of gas with no issues. Ran great through the midrange and no more struggle to get up to high RPM. No more rough sound or almost a miss cruising around the 4k range. I guess I need to find the correct cap, but for now this fix worked. I just don't want the valve to be able to slide down too far and hit the piston (can it even do that?)