08-17-2009, 02:47 PM #1
Barely moving in the water! Need Help!!!
Had my 1998 SPX out on the river yesterday. It still does not want to move very fast! (Maybe a walking speed!???)
Things I've done or noticed since acquiring the ski a few months ago:
1.) Rebuilt top end. 150 psi on both cylinders. All is good there.
2.) Changed out grey fuel line.
3.) Cleaned carbs really well… but didn’t rebuild. Cleaned RAVE valves.
4.) New wear ring. Gap is about 0.1 mm. (Dang near closed off!) I used silicon instead of a neoprene seal when putting the pump back on… but that shouldn’t matter does it?
5.) Rebuilt drive shaft with new slip ring, carbon ring, and seals.
6.) No signs of slippage going on in the PTO splines or drive shaft splines. I think I’d see something chewed up or at least ground down if this was going on?
7.) It has a Solaris prop. It has some slight wear but doesn’t look really bad at all. No deep gouges or nicks.
8.) Pump vanes are not broken. All looks good.
9.) Ride plate looks sealed well.
The engine cranks and throttles really well while on the trailer with a hose. However, it doesn’t take a throttle well in the water and didn’t want to rev up really high. (I didn’t have my tiny tach attached so not sure what the real rpm’s were.) Still I’m turning up the water behind it really good! Good enough that I think it should be moving a whole lot faster than a walking speed! But it is nowhere close to wanting to be able to plane out. Is it sucking air from somewhere and cavitating?
Tonight I plan to take the carbs apart again and check the filters for any blockage. What else do I need to check??? I’m running out of ideas!
08-17-2009, 06:42 PM #2
- Join Date
- Sep 2007
I know it sounds simple, but did you change the spark plugs? My GTX ran the same way once a few years ago, and I found out that it had a bad plug.
08-17-2009, 09:37 PM #3
I clipped the end of the wires and put new plugs in before I hit the water with the new rebuild. But this is actually 3 times I've gone to the river thinking I might have fixed the problem... only to find out that I have not. The engine might have 30 minutes of run time on it by now. (Not saying the plugs couldn't have fouled already.)
For grins I'll try new plugs again. That would be a quick $5 fix if it actually works!!?? Thanks for the idea.
Any more out there, guys???
08-17-2009, 11:13 PM #4
Was the ski running ok before the rebuild? What is your jetting what n/s, what pop off pressure and spring? When you take it to the water next time back it down and have it tied down good. Have some one to work the throtle while you are behind it and see what kind of thrust you have compared to one running right. This will help to determin that you are not sucking a lot of air at the pump.Really need more info on exactly how the boat is acting in the water. What rpm when you are in the water and giving it throtle?
08-18-2009, 08:53 PM #5
Sounds like a dead cylinder. Try pulling the plug wires one at a time while in the water running on the trailer. See if one makes it die and the other changes nothing. Then find out why. You missed something!
08-19-2009, 08:06 AM #6
Did you clip the wires at the coil end? Are you sure you hooked up all your fuel lines correctly?
08-19-2009, 09:38 AM #7
Why would anyone take out their carbs and clean them and not even rebuild them is beyond me?? The 2 micro filters in the carbs could be full of junk and the fuel selector switch could be gummed up with the old fuel line. Your ski is 11 years old.. Spend the 100 bucks and do it right before you buy another top end, which was probably caused by your carbs in the 1st place...
Those fuel pump diaphrams can warp and cause the carb to not pump enough fuel into the engine. Your pulse line could have a tear in it...
08-19-2009, 12:50 PM #8
"Why would anyone take out their carbs and clean them and not even rebuild them is beyond me??... "
Ha! Easy answer... its called the WIFE!!! And yes she's aware of every dime I spend on these water toys. (I've recently bought and rebuilt five skis. Told her upfront I could buy, reupholster, and have all five running with a budget of $5K. She agreed so now I've got to do my part. I'm still $500 below that budget and she and I had four of them on the water this weekend with our family!)
But I do agree that $100 now is a lot better than $400 later if I have to rebuild the top end again on this one! Doing a top end again would definitely bite. If I can get some free time in the garage I'll try and trouble shoot this one some more. I do think it is in the carbs... because the top end is thankfully still showing 150 psi on both cylinders.
08-19-2009, 01:03 PM #9
Did you clean the filters in your carbs when they were apart?
08-19-2009, 02:54 PM #10
Yes... the carbs were clean as a whistle when I put it all back together. (Along with new fuel lines too.) Nothing looked worn at all and that was the primary reason I didn't rebuild them.
The ski runs great on the trailer and hose. Immediate throttle response with high quick revs. I was just suprised it didn't do that in the water too! I'll take my Tiny Tach out to the river with me next time to see what rpms I'm actually getting. The thrust it seems to be generating in the water sure did look sufficient! It just didn't move the ski more than a fast walking speed. As mentioned before... its not my wear ring because gap is only .1 mil... but I'm not completely ruling out the leading edge of the impeller just yet since it is a little ding up in places. (Not bad at all but not new either.)
I'm going to put new plugs in and check carb filter screens just as soon as I can. I plan to be on the river again Sunday afternoon... so I'll slowly start the deduction process.
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