12 replies to this topic

[ijetskilc]

I have 1997 challenger that starts,idles and has great compression but just won't get up and plain off.I did notice that the pressure valve on top of the waterbox/muffler is leaking water out the bottom .I known this needs to be corrected but could this be my problem?It is a single engine 787.I really don't know were to start.

[ijetskilc]

ijetskilc, on 15 July 2011 - 09:44 AM, said:

I have 1997 challenger that starts,idles and has great compression but just won't get up and plain off.I did notice that the pressure valve on top of the waterbox/muffler is leaking water out the bottom .I known this needs to be corrected but could this be my problem?It is a single engine 787.I really don't know were to start.

Come on guys Help!

[Kevin Leclair]

It could be part of the problem, but along with that what kind of shape are your wear ring(s) in?

[ijetskilc]

Kevin Leclair, on 16 July 2011 - 04:31 PM, said:

It could be part of the problem, but along with that what kind of shape are your wear ring(s) in?

The wear ring(1) looks fine no clearence issues, no cavatation.The carbs have been gone through and the fuel lines replaced.

[Kevin Leclair]

Got it, I missed that you said a single engine initially.  How does the impeller look?

[ijetskilc]

Kevin Leclair, on 16 July 2011 - 09:01 PM, said:

Got it, I missed that you said a single engine initially.  How does the impeller look?

The impeller looks fine,It's not a drive issue.

[ijetskilc]

ijetskilc, on 17 July 2011 - 09:25 AM, said:

The impeller looks fine,It's not a drive issue.

Could someone tell me where the rectifier is on this thing?

[Overkill]

If you haven't fixed it yet, a little more info would help.  Does the engine rev to 7000 or does it stall?  Will it only rev to a certain rpm?

[ijetskilc]

Overkill, on 03 August 2011 - 09:57 PM, said:

If you haven't fixed it yet, a little more info would help.  Does the engine rev to 7000 or does it stall?  Will it only rev to a certain rpm?

I replaced the pressure regulator thats on top of the waterbox and that help a lot but still it very slow to get up on plain sometimes if you pump the trottle it catchs and goes up to full speed(this is not a drive issue believe me!)I known with regular seadoos the fuel valve(petcock)can give you fits but the way this one is set up how on earth do I go around it?

[Overkill]

I also had a problem with my water regulator.  The only effect from fixing it was a 200 rpm increase on top end.  It sounds like you are describing a lean condition in the mid-range.  If you get over 4000 does it then run good?  Can you go up and down between 4000-7000 with no problem but have a hard time getting from idle to 4000?  If that describes it I have the same problem and have been trying to fix it for the last month.  Carb is perfect so I'm starting to check through the electrical.

I don't know how to bypass the fuel petcock on the single engine.  My twin is easy beacuse the filters are right by the tank.  Have you checked the manual for a schematic?

[ijetskilc]

Overkill, on 04 August 2011 - 06:54 PM, said:

I also had a problem with my water regulator.  The only effect from fixing it was a 200 rpm increase on top end.  It sounds like you are describing a lean condition in the mid-range.  If you get over 4000 does it then run good?  Can you go up and down between 4000-7000 with no problem but have a hard time getting from idle to 4000?  If that describes it I have the same problem and have been trying to fix it for the last month.  Carb is perfect so I'm starting to check through the electrical.

I don't know how to bypass the fuel petcock on the single engine.  My twin is easy beacuse the filters are right by the tank.  Have you checked the manual for a schematic?

This boat when you hit the trottle it goes up to 5000 and just stays there for about a 30 sec. to a min. and then takes off.If you pump the trottle sometimes it will catch and goes up to 7000.but if you go below 5000 its back to the same old thing, slow pickup.Anthing above 5000 is normal.If I get more than two people in the boat forget about plaining off and don't even think about trying to pull a skier.

[Overkill]

Could be a fuel pump problem but you said the carbs were gone through.  Check the pulse line that goes from the case to the carbs.  A crack will cause poor fuel pump performance.  
Was the fuel filter changed?
Have you done a plug chop?  What you are describing sounds like a severe lean condition on the main jet circuit.  You could really damage the motor if that's what it is.  Mikuni's are picky and have to be set-up right.

Another thought is the synchronization of the carbs.  If they aren't opening together it can cause all kinds of weird problems.  

Good luck.

[Wild Goose]

Hey guys, this sounds like the same thing my boat (98 Challenger 1800) was doing at the start of last year, but only the port side engine as I recall.  Basically I would open up the throttles and the engines would run up to about 4 or 5,000 rpm and stay there, the starboard would continue to climb slowly and get the boat on plane, and the port would kick in like a turbo unexpectedly and I'd be off and running with both at 7,000.  Sometimes the port engine would hunt between 7000 and 5000, generally giving a very uncomfortable and unpredictible ride.  After about an hour or two of running the boat, the issue cleared up, but I can only assume it will come back to haunt me this spring, and I also want to resolve it before I do any damage.  Because it cleared up, and my Sea Doo is used so infrequently (about 1 or 2 tanks of fuel a season) I am assuming it is gummed carbs or a fuel delivery problem.  I have also not cleaned the RAVE valves since I have owned the boat, so I plan to do that along with the carbs and lines (in my free time - as if I have any!).  Does anyone out there have any ideas?  While I am in there, I don't want to miss something simple.  Much like the original post, this is not a drive line problem, because when I got full RPM range, the boat performs like a champ.