Air bubbles in fuel lines

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JeremyD615 said:
A tiny tach is a great idea if you don’t mind having the non factory gauge there. They’re super simple to install and give you quite a bit more functionality than the stock tach...
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And it can be an alternative until another replacement is located. In this case the tiny tach can be kept handy for future needs once the preferred tach is installed.
 
Might measure the voltage on the grey tach wire at the tach while the engine is off, there should be some DC voltage there I believe b/c the stator is always at battery voltage DC if I recall from the schematic. ie: All 3 yellow wires of the stator should be at battery voltage, depending on how the charging system is wired, I believe yours is wired this way as Seadoo often does with three phase stators using 3 yellow wires.

In case you prefer to investigate further. If no voltage on the three yellow stator wires we'll take a closer look.
 
Sportster-2001-951C-Stock said:
Might measure the voltage on the grey tach wire at the tach while the engine is off, there should be some DC voltage there I believe b/c the stator is always at battery voltage DC if I recall from the schematic. ie: All 3 yellow wires of the stator should be at battery voltage, depending on how the charging system is wired, I believe yours is wired this way as Seadoo often does with three phase stators using 3 yellow wires.

In case you prefer to investigate further. If no voltage on the three yellow stator wires we'll take a closer look.
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I measured the voltage on the yellow wires coming off the mag. There are 4. I tested positive on the yellow wire and negative to the negative post of the battery. Each wire came up between 11.8 and 12 volts. So it seems that the voltage is good and something in the tach is not getting the signal even though it zeros out and lights up with the key on. It's a shame.

I may still try to fix it but if the fault is in the winding that's a deal breaker. It's raining here for the next few days so no boating, again. I guess I'll dive into the tach a bit further.
 
Brought er down to the lake. Started up and ran great while I docked it.

Put the car away but when I came back and tried to start the boat again it wouldn’t. It turns over strong, and tries to start but it doesn’t quite fire. I’m getting a compression meter since mine is bad. Going to check the compression when I get back :/

All systems were working perfect otherwise. And it didn’t sink so that’s good lol
 
JeremyD615 said:
The best way to remove the decals is to use a heat gun and gently get underneath them with a razor blade. Once you get the decal itself off, use some adhesive remover (Goo-Gone or Turtle Wax Decal Remover) and a scotchbrite pad to clean up all the residue. If you don’t like the idea of scaling the gelcoat with a razor, you can use those decal eraser wheels that chuck into a drill, but they don’t last long, so buy two or three of them if you go that route...
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tried that but found a better way, same way we remove decals on cust cars.

An eraser pad, used on my HX removing damaged decals since the heat gun and razor method wasn't working. Had them removed in minutes. There's a tool for it. But I just attach it to my drill. Very good in my opinion
 
Ok did the compression test.
1. Removed both plugs
2. Placed tape over both cables since I have no grounding plus.
3. Placed comp gauge in MAG then PTO cylinder.
4. Tested each with wide open throttle, as mentioned in other threads.

MAG: 140
PTO: 141

Guess my compression is good. Maybe my pop off pressure is messed up or the seats are allowing fuel to leak? That is slightly frustrating. But keeping my wits about me!

0F6C206C-BF8A-457D-B99F-EE4261835625.jpeg0AE0707A-89B3-4AF0-B881-07431E3DC764.jpeg
 
needle and seats, I'd recheck popoff make sure it's an actual pop and not a slow leak then pop. use wd40 when testing it, more detailed instruction will be the carb rebuild sticky
 
noviceskier said:
needle and seats, I'd recheck popoff make sure it's an actual pop and not a slow leak then pop. use wd40 when testing it, more detailed instruction will be the carb rebuild sticky
Click to expand...

I'm going to pull the carbs tonight and check the pressure. I'll hit harbor freight for some supplies to build the device.

Last night I hit the lake on the conoe. Nothing more reliable that oars lol
 
Nice tester, that should work great. :) BTW, if you let it idle slow in the water it's more prone to loading up on fuel than if you give it some throttle to keep it cleared out. Might just be a little too much low speed fuel and turning in the idle mixture screws a little helps.
 
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Can someone confirm that this procedure is correct for testing compression and that the results above from my test look good for the 96 seado challenger 787 motor? I think I asked the same question in a different / incorrect thread accidentally.

1. Remove both plugs
2. Place tape over both cables since I have no grounding plus. (I will get the grounding plate)
3. Placed compression gauge in MAG then PTO cylinder.
4. Tested each with wide open throttle.
 
Yes, although #3 it doesn't matter what order you test the cylinders.

Also some engine builders suggest leaving one plug in and others don't so that is up in the air.
 
So what do you think, should I pull the carbs and do a pop off test or take it back to the lake and let it run for a while?
 
Running it more will not fix it. If you have a running issue it needs to be resolved.
 
mikidymac said:
Running it more will not fix it. If you have a running issue it needs to be resolved.
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You’re right. I was just being lazy.

I’ve removed the carbs and conducted the pop off tests. The first is the mag then PTO. The mag pops around 30-35 and drops 5 PSI.

The PTO pops about 30-35 and drops roughy 5 PSI.

Both seems to seat and hold pressure.

Do these results seems right for the 787?

Thanks!
 
JeremyD615 said:
I believe that’s within the range, and the fact that they are close is a good sign...
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Great thanks. Welp, brining it to the lake now to try it out. Prob not a good day for a test being that it’s the 4th lol

I also discovered that my dang auto bilge water sensor is not working. Fuse is good, bilge runs fine, sensor wires ring out to the large connector on the fuse block in the helm. I can bridge the wire at the connector but still no dice. The fuse block in the helm has what looks like a relay built into it. Wondering if that’s NG.

One thing after another. But I think I’m getting close.
 
Ok took it to the lake. Ran it for an hour or more.
1. Ran good. Very harsh water today so took some effort to plane.

2. Used what seems to be very little oil. I know the pump works. And oil lines are full. The oil shaft is new as well and I’m sure after an hour plus at 1/2-2/3 throttle it would have seised if it wasn’t getting oil. Seems strange that little was used though.

3. This part I worry about. Around when I was going to head back in I had throttle at 1/2 and it seems as though the engine was slowing down. I’m not sure if it was the choppy water or not. I had it running for quite a distance to get back to the launch and it seemed fine. Not too sure.

4. Even thought it ran great. I shut it off for about 10 minutes and she wouldn’t start. The pop off test seems good but I guess I’m pulling the carbs again.. We’ll get there.
 
Make sure you test the carbs for leakdown once they are all back together. Should hold 10 psi for ever.

They do use very little oil, that is the beauty of oil injection.
 
Sportster-2001-951C-Stock said:
The math works out roughly to 1 gallon of oil consumed with 50 gallons of fuel. That's about a quart of oil to every 12.5 gallons of fuel.
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I marked the oil tank level before heading out. how much oil can that tank hold? It's around half full right now.

I ran the boat for a little over an hour at idle to about 1/2 to 2/3 throttle for most of the time. I don't see much of a drop at all. I would think it would drop the level 1/8" to 1/4" after that amount of time. Maybe it's just me being naive. I'm also OCD so I'm going to pull the oil pump again to make sure the shaft is still secure lol I'm learning a lot but I had no idea how foreign these boats would be to me. It's good to learn though.
 
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