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Surging and i'm tired of it

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old44272

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I have a 1999 Challenger 1800. The starboard engine is surging. It starts to surge above 4000 RPMs. In other words, it seems fine up UNTIL 4000 RPMs, then anything after that it surges, like it can't take the fuel, then something happens and it jumps up to 6000+ RPMs (where it should be compared to the throttle), then immediately jumps back to the 4000 RPM range.

I just rebuilt the carbs and there is NO DIFFERENCE.

Next up I'm replac

ing the external fuel pump. I pulled it off and it looks nasty.

The only gray line was the pulse line to the crankcase from the fuel pump. It did look nasty and will be replaced.

Both big fuel filters are new.

Like I said, the carbs were just rebuilt with new diaphrams, gaskets, filters, etc. NO DIFFERENCE. The boat runs exactly the same as it did before carb rebuild.

Am I on the right track with the fuel pump? What about the accelerator pump. I'm pretty much a newbie with these engines, and this one is driving me nuts.

BTW, the other engine runs fine, so it's not the fuel......

Thanks for any suggestions.
 
Yeah i am with the other guys. You are describing a RAVE valve sticking. It is easy to do and there are tons of threads here on how to do it.
 
Ok. Great news. I'm leaving this post because I hate reading threads that just stop with no conclusion. When you are looking for an answer to a problem, it's nice to know what worked and what didn't for a particular problem.

Anyway, I got the new fuel pump and installed it. The fuel pump thing was probably unnecessary. Although the old fuel pump did have a bunch of crap in it (looked like fine sand).

While I was waiting for the fuel pump I worked on the RAVES. The valve to the rear of the engine gave a little tension pulling it out. When I did get it out it was gummed up with CHUNKS of carbon buildup. I cleaned it and sanded it to get it clean. Then I reinstalled it with a new O-ring and a new gasket.

I then took the one out at the front of the motor (Mag side). It was gummed up too, but not as bad. I cleaned it the same way and reinstalled it with a new o-ring and gasket.

SOOOOo,,,,I put the boat in the water and PROBLEM FIXED. No more surging. The boat ran great.

I'm pretty sure with the way the first valve had the sticky tension on it that the problem was the RAVE valve and not the fuel pump. Time to clean the RAVES on the other engine.

Thank you for those that replied to my problem. What did we do before these forums? Thanks again!!
 
thanks for posting the final result and solution.

Yes, this forum is the best thing since sliced bread :)
 
You need to service the RAVE valves at least annually. Also be sure to use full synthetic API-TC oil.

Lou
 
Glad it worked out for you. When you notice a high RPM surge, the RAVE valves should be the first suspect. I pull mine out every spring and clean them before I take the boat out. They always looks new.
 
Don't want to high jack the thread but it appears like the problem is fixed and I'm having a similar problem. My challenger is single engine dual carb. I cleaned raves and carbs fairly well but only changed out rave o rings. I idle fine but when I get to 2000 or so Rpm it starts to hesitate and make a bogging sound until 6500 rpm. Then it runs fine tip 7k where it tops out. If I get down to 6400 it drops to 2500 and loses power til I get back to 6500 or so. Is that hesitation to much has or air? Any ideas on problem.
 
old44272 said:
Ok. Great news. I'm leaving this post because I hate reading threads that just stop with no conclusion. When you are looking for an answer to a problem, it's nice to know what worked and what didn't for a particular problem.

Anyway, I got the new fuel pump and installed it. The fuel pump thing was probably unnecessary. Although the old fuel pump did have a bunch of crap in it (looked like fine sand).

While I was waiting for the fuel pump I worked on the RAVES. The valve to the rear of the engine gave a little tension pulling it out. When I did get it out it was gummed up with CHUNKS of carbon buildup. I cleaned it and sanded it to get it clean. Then I reinstalled it with a new O-ring and a new gasket.

I then took the one out at the front of the motor (Mag side). It was gummed up too, but not as bad. I cleaned it the same way and reinstalled it with a new o-ring and gasket.

SOOOOo,,,,I put the boat in the water and PROBLEM FIXED. No more surging. The boat ran great.

I'm pretty sure with the way the first valve had the sticky tension on it that the problem was the RAVE valve and not the fuel pump. Time to clean the RAVES on the other engine.

Thank you for those that replied to my problem. What did we do before these forums? Thanks again!!
Click to expand...

When they are gummed up real bad like that, Easy Off Oven Cleaner is the way to go.
 
your selector switch itself may be clogged, try switching over to reserve and see if it makes a difference. did you take the little filters out of the carbs and clean them? did you replace the fuel filter?
 
I took off the selector switch and cleaned it, I can easily blow through both res and on. I did replace both fuel filters in the carb. I cleaned the water/fuel separator thingy up by the fuel tank baffle.
 
I had a problem recently with my 96GSX, similar to what you're talking about, I thought for sure it was fuel delivery related. Turned out to be ignition, it was the voltage regulator. Just a thought.

Lou
 
Check for A/C voltage across the battery while reving the engine to test for a bad rectifier.
 
I am sure you have already looked, but I have read on a couple other posts to inspect your wireing for any corroded connectors.

My new project boat (1998 Challenger 1800) is having the same issue. so I have been looking around for answers. seens this might also be a common fix with the rave valves.

good luck, and please post a fix when you find one...
 
Ok so I have to ask how to check ac voltage on the battery. I thought these boats only had dc. Out someone could kindly tell how to check it and what numbers I'm looking for I would appreciate it.
 
jabroni1m said:
Ok so I have to ask how to check ac voltage on the battery. I thought these boats only had dc. Out someone could kindly tell how to check it and what numbers I'm looking for I would appreciate it.
Click to expand...

see attached explanation by Bills86e

Bills86e said:
The charging system on a Sea Doo is quite simple, but often mis-diagnosed. The stator puts out three-phase AC power, which is rectified into DC, then regulated to a max 15 VDC. A common problem is for one or more of the diodes short out, and pass the AC into the DC system. If you rev the engine and measure voltage with the meter set on DC, you might not discover that you are actually injecting a large amount of AC, which screws up the MPEM at high RPM, a very common overlooked problem. The electrical Havoc is more prevalent after 4-5K rpm's.
Simply switch the meter to AC and rev the engine, should not see more than a volt of AC; if you see several volts, your rectifier is blown.

Bills86e
Click to expand...
 
So I check the A/C voltage across the battery with engine started at idle and revved it up to over 5k, it momentarily when touching the terminals showed .1 or .2 volts, but then went to 0 and stayed there. It never went above .2. So does that mean the regulator is working correctly?

bigJake said:
see attached explanation by Bills86e
Click to expand...
 
Been real busy at work. Sorry haven't posted on problem or update in a while. So the boat is still missing/surging/bogging from 2500 to about 6k. U pretty much can't run it in that range. You have to floor it up to 6k to get it to run right. My question is, I have a water leak coming from where the exhaust connects to the engine area. On the parts fiche. Its leaking from where part 48 is on http://partsfinder.onlinemicrofiche.com/seadooforums/Seadoo_oem/Seadoo_JB.asp?Type=13&A=17&B=6 Its leaking where the gasket that goes to the head pipe assembly is. I have the gasket, just having a problem getting the bolts loose and off. My question is, could this leaking water out even cause the carb problem I'm having?



jabroni1m said:
Well I guess i'll buy rebuild kits and redo the carbs instead of just cleaning them again. I was thinking about going with http://osdparts.com/index.php?main_page=product_free_shipping_info&cPath=1&products_id=38 or
http://www.shopsbt.com/sea-1997-dch/35-160.html

Any recommendations? Also, I did not do a pop off test, but just got my tester in. Could that cause this problem?
Click to expand...
 
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