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Need to get this boat running... 97 challenger

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I just picked up a 97 seadoo challenger today and need some help with it. After cleaning the carbs I can get the engine to start with choke and idle okay. If I give it gas it will die right away every time unless I hold choke open slightly it will get up to 3000rpms. I know my carbs pretty well since I've owned over 10 different pwc's. I near positive its not a carb problem. If I get the engine running fast enough I can get it to backfire. Here is the history of the engine. It has multiple colors on it, one cylinder is white, one is silver same with the head and other parts. So someone has been through the engine. The oil has been drained and blocked off. Im not sure if it was done right yet so I leave oil in the tank and premix.

So my question is where do I start? Compression is 148, 155. Im guessing the rotary valve wasn't timed correctly. Does anyone agree? I need to get on the water this next week, its going to be 90 for the next 7 days!
 
At face value... I would say it a lean condition at the carbs... but checking the RV can't hurt. Since the carbs and manifold need to come off to check the RV... I would do all of it at once. Also... since it's mix of parts... I would verify that the jetting in the carbs is correct, AND that they are 40SBN carbs. (the 38's look the same)
 
Thats what I thought at first too, but I have messed with many carbs and I think I know how they react. Do you happen to know the stock carb settings for the 97 challenger single engine? I can't seem to find it and was trying with stock 787 from other skis. What should the jetting be in these carbs? I forgot to check the jets but seat was at 1.5.
 
If you know how they react... then why would you think it's NOT lean, if you have to hold the choke? The choke is adding vacuum, and in turn, draws more fuel.

Now... that lean condition can be caused by a mechanical issue... like improper RV timing, or extremely high pop-off.

But... you have my opinion. Now, go verify the RV.
 
Yeah I was testing the settings and it looks like its right according to the plugs, but I very well could be wrong. I pulled the rotary valve cover and the timing was right so I guess I will move on. The carbs are off again so I will pull them apart again. I have no way to test the pop off right now. What all should I check with the carbs off?
 
Also I forgot to mention I couldn't get the jets cover off one carb because someone stripped it. I am going to get a extractor and see if I can remove it. could that cause these problems if one carb had clogged jets?

Mag High speed jet is 142.5, pilot 65, pop off spring is silver, seat 1.5.
PTO High 145, pilot 65, spring silver, seat 1.5.

Any reason to replace the gas lines on this model? I know old ones were bad.
 
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I got the screw off and cleaned everything. These look perfect shape as long as the settings are right. Can anyone confirm? Also I still have no idea where to set the high and low speed needles.

The pop off pressure does seem a bit high compared to other carbs I have rebuilt.
 
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So I took it out again tonight, It starts and idles perfect up to maybe 10%. I set the low speed needle at stock settings but I still can't find high. It doesn't backfire as much anymore, but still has no power. Plugs were slightly oil fouled, so maybe the small amount of old gas in it is causing problems?
 
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Well... your carbs are lean right now. The OEM jetting for that boat is:

High MAG: 145 PTO: 140
Pilot: 67.5
LS: 1 turn
HS: 0
Pop-off: 38 psi

When you had it apart... did you check the RV clearance?
 
When you say they are lean do you mean I need to adjust the high speed needle? That exactly what I had them set at. Should I take it all apart again and check the RV clearance?
 
Could it possibly be the electrical? I have a 96 xp with the 787 engine, could I swap some electrical parts?
 
I just had it out for a few hours trying to get the carbs going. I think your right on the carb problem partially. After filling the tank with properly mixed 40:1 oil I put new plugs in and checked them. They were both white after a little riding, so I turned the highs out. The mag plug I can get to turn good brown with about 4 turns out, but the pto stays white with even 6+ turns. Im attaching a picture of the pto, it has a weird build up on the one half. Could pop off cause this problem? The jets are clean. Im going to pull the pump to make sure that isn't messing everything up.
20120630_163116.jpg
 
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As Dr Honda said, your jets are wrong to begin with.

You need to install the correct jets for that engine.

High MAG: 145 PTO: 140
Pilot: 67.5
LS: 1 turn
HS: 0
Pop-off: 38 psi

You said you were running 142.5/145 with a 65 pilot. It almost looks like they are backwards, plus the pilot is wrong also. I believe that could give you a lean condition.
 
I think the reason my jets are different is because of the accelerator pump. Im reading they used lower size jets on them.
 
Generally, on the carbs with the accelerator pumps, they will have a smaller pilot jet... but bigger mains to cover the over all fueling. Also, more than about 3 turns out, and the needles don't do much.

You need bigger mains, and the verify the pop-off.
 
I pumped it a few times when I pulled the carbs apart and it squirted fuel out. So I think so? I don't currently have a pop off pump. I think I might make one tonight. What size mains do you suggest? Also I don't remember ever seeing my tac go above 3k rpms. Maybe its some sort of rev limiter?
 
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If you are testing it out of the water, it will not go above ~3000k. This is to protect the engine when there is no load. It is difficult to really test an engine out of the water.
 
1) If its in neutral... it won't go past 3500 rpm, and testing out of the water won't tell you anything.

2) Without knowing the pop-off... there is no reason to do anything else. It's a critical adjustment, and if it's too high, you won't get fuel.

3) I already listed your jetting.
 
1. Is there a way to test my switch or is the fact that it won't start in forward good enough?
2. Im going to throw together a pop-off guage today.
3. I ordered the jets but do I really need them if they have the accelerator pump?
 
I installed the new carbs. Again it starts great but backfires at around 2500 rpms. I have the pilot jets right and the mag high, the high pto will come in the mail friday. But im only 2.5 off. I don't think that should make any difference that I can't adjust with the needles. Could it be possible the mag timing is off?
 
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