1997 Challenger 1800 Engine not fully revving up

[scottgute]

I have a 1997 seadoo challenger 1800 that one of the engines is not fully revving up, when trying to pull someone and take off, the one engine fully revs up to like 7k or so, the other will only hit 4500 - 5k. I did just cleaned the rave valves off. Mainly worried about the valves themselves. If the bellows have a small hole or anything like that, could that cause this problem? Any other ideas?

 

[Murph_13]

Sounds like the water regulator, I'd check it for leaks. The water regulator is on the water box/muffler and has the exact same cap as your RAVE valves. If it is leaking or not getting sufficient water supply you will have the exact problem you're having...the engine will not achieve max RPM and typically will only reach 4500-5000 like you're seeing.

 

[scottgute]

I am completely new to these, so what exactly would I be looking for? How can I verify if there is a leak, other than say the cap being cracked or something similar, or if it is getting enough water?

 

[parrothd]

Did you check the accelerator pump is working? Also, there was a recall for that year boat to update the rave vales and update jetting to correct that...Search the forum..

 

[scottgute]

Again, I am a newbie, so how can I check that the accelerator pump is working?

 

[parrothd]

Start the boat for a minute or so at idle, then stop it. Take the air box off, take the metal screen out, look into the carb body and have someone move the throttle from idle to full with the engine off. You should hear and see a small squirt of fuel. If not you'll need to dissemble the accelerator pump and clean it and rebuild it if needed. The small squirting jet in the carb can get clogged too...

 

[Murph_13]

I had the same problem that you described, max engine RPM of 4500-5000. My water regulator valve was leaking at the water box fitting. I could see evidence of the leak. A quick check would be to run the boat at full throttle up to speed and check the outside of the valve and water box for a leak. You could also check the feed line from the T-fitting to the water regulator for blockage. This is from the service manual for the 787 engine:

If the maximum engine speed can not be attained
or if the engine has poor performance, the water
flow regulator valve should be considered in the
troubleshooting of the problem.

The water regulator also has a bellow inside that may be leaking? I never had an accelerator pump issue with my boat, so I can't speak to that or what symptoms it might produce if faulty.

Good luck with resolving the issue.

 

[scottgute]

So I took a look at it more closely and found that the engine is leaking water. Guessing this is not a good thing. I have attached an image of where the water was coming from. Anbody have any ideas what my problem may be now?

 

[scottgute]

How do I take the water regulator off? Do I just remove the the hoses, and unscrew it from the exhaust below it? I have the manual, but not quite following it. The instruction just says "remove fitting from valve housing", does that mean to just unscrew it? I am assuming yes, but wanted to make sure.

 

[Murph_13]

The water regulator has a fitting that threads into both the water box and the water regulator housing. You will need to reseal it at both places using Loctite 592 or equivalent sealant. Did you notice any leakage at the water regulator? Or are you just looking to remove it to disasseble and inspect?

Are you sure you're leaking water at the location that you show in the picture...that is not good if you are...you'll have to pull the cylinder head and find out why it's leaking there...hopefully just a gasket...

 

[scottgute]

Need to pull the water regulator as it was dripping, and when I opened the cap to look, the clamp around the bellow was off, so going to put that back on. I am about 95% sure that is where the water was coming from, I am going to try to reverify tonight. Is it very hard to pull the cylinder head, again, you are dealing with a novice here, and my manual is at home? If it is very involved, I might just bring it in then. Thanks for all the help.

 

[Murph_13]

I would get the leak on the water regulator straightened out and you should be back to normal operation...somewhere near 7000 RPM on both engines. Then I would try to verify whether or not you actually have a leak at the cylinder head/cylinder head cover. It's not hard to pull the cylinder head cover or cylinder head, you'll just need to make sure you torque them back down properly. Proper sequence and torque.

I would address the regulator issue first and see if you're back to normal operation. If you are leaking at the cylinder head cover/cylinder head and it's doesn't appear to be a major leak, I might hold off on doing this repair until after boating season if your concerned about your ability to make this repair (of course I'd keep an eye on it for getting worse). If you had a closed cooling system (which you don't...cooling comes from lake water being supplied by the pump) I would definitely be more concerned since you'd run the risk of a low coolant situation and overheating the engine. You have a temperature sensor in the cylinder head that would give you an audible warning if you had an overheating condition. Again, as long as the leak does not seem to be a significant one and you are not leaking water into your combustion chamber (check spark plugs) then I'd hold off unleass the leak gets worse.

 

[scottgute]

Unfortunately the slight water regulator leak is on the opposite engine. The low rev engine is the one with leak in the picture above. I have not had the audible warning, so that is a good sign. I will pull the plugs and check to see if I see any water in there. Guess I will be hunting for a torque wrench soon.

 

[Murph_13]

You're not going to find water in the cylinder or on the spark plug. Pull both plugs and compare the appearance. If you have water getting in the cylinder near the leak the face of the plug or coloring around the top will be lighter in color than that of the plug from the other cylinder and you may also find that the plug gap has grown.

If the water regulator is leaking on the engine that reaches 7000 RPM, that's surprising. You may want to check the engine that is not reaching top RPM for water flow through the engine...make sure you have water coming out of the bleed hose...you should have water coming out through both bleed hose fittings on the transom by your tow hook. If not, your cooling system is plugged somewhere and maybe your not feeding water through the water regulator into the tuned pipe?

 

[Plopansr]

I have the same problem on my 2001 challenger. The port engine will only rev up to 4000 rpm while the starboard engine is fine at 7000 rpm. I noticed a lot of smoke coming out of the engine compartment, and when I brought it in, I was told that the exhaust was somehow blocked up. It's awaiting parts now, I will post an update when I get her back!

 

[scottgute]

Is the proper sequence inside out, torque to 12ft/lbs, then repeat to 17ft/lbs? Can start on any inside one (closest to middle) and work my way out?

 

[Murph_13]

That's right for the Cylinder Head Cover to the Cylinder Head. The torque values for the Cylinder Head to the block are 15 lb.ft. and then 30 lb.ft.

 

[Codyturgeon]

Same problem

I have the same problem on my 2001 challenger. The port engine will only rev up to 4000 rpm while the starboard engine is fine at 7000 rpm. I noticed a lot of smoke coming out of the engine compartment, and when I brought it in, I was told that the exhaust was somehow blocked up. It's awaiting parts now, I will post an update when I get her back!

Hey any news on your plugged exhaust. Did you end up having to replace it or were they able to unclog it? If so do you know how they did it? Thanks