1997 SeaDoo Challenger 1800 hesitation/stalling on acceleration

[Armand_Hammered]

Hey everyone, i just want to say ive learned so much about my boat from these forums, and you guys, especially seadoosnipe, thanks for everything. ive read every post related to the challenger and found people with similar problems to mine but nothing exactly the same.

My problem is that when i accelerate from a dead stop my drivers side engine will either stall if I advance the throttles to quickly or if i slowly move them forward it will rev up to 5000 rpms and then stay there while the other engine increases to 7000 rpms. The drivers side engine will soon increase to 7000 but only after hesitating at the 5000 rpms level for a few seconds (up to 5 seconds).

I have just cleaned all the rave valves in both engines (great tutorial by the way) over the winter and havent had a chance to try the boat yet as my lake is still frozen, but im just wandering in case the rave's werent the problem if anyone has had a similar problem, or any ideas on what might cause this ?

Thanks.

 

[seadoosnipe]

Raves....

Your problem sounds localized to the performance of either a dirty rave valve or maybe a bad bellows.
You said you took them out and cleaned them. Did you put them back from the same port from which they came? On your adjustment (red cap), try running it all the way in. The manual actually says to adjust them out flush to the housing. But after some debate in the forum, I found that mine run better, all the way down.
There is also internal porting in them where the pressure port has to line up with the flange of the valve. I don't think you can reverse that. I'll have to see if they are only capable of being installed in one way.
But, your description, does point at a rave valve problem........
I'll probably get back to you on this one, since I have a spare set of RAVE's on the workbench......

 

[Seadoo_sportster]

my sportster had a similar problem, push the throttles up from idle, the engines might stall, advance slowly they would do fine, then at a high rpm they ran like a champ. at the low rpm the carbs have a "fuel pump" internal to them. Bought two rebuild kits from Denniskirk.com, rebuilt them and they run like champs!

 

[seadoosnipe]

Carb kits.....

Welcome to the forum "Seadoo Sportster", nice to have you. The problem experienced in acceleration, with the engines sounding smooth, but not just wanting to get over the hump, then "pow", takes off like a banshee, is normally the RAVE. You can never discount other areas though when trouble shooting, as you have brought up. On the Sea-Doo naturally aspirated, carbureted engines, the carbs (Mikuni 38-40i) fuel line from the gas tank comes in at the MAG carb, where it is moved by a pump known as a "pulse" pump. It has a line that attaches from the Mag carb to the engine block that powers the fuel pump system.
Your website you suggested has some nice stuff. Do you shop there often or are you a thrifty shopper like most of us in the forum. (Toys are expensive to maintain)?.......if so, the Mikuni carb rebuild kits are $12.99 higher than where most of us shop for our carb kits. But they do offer some cool stuff!...Welcome to the forum.........

 

[Seadoo_sportster]

Cheaper kits? I thought i was getting a deal, where are you all shopping?

 

[Seadoo_sportster]

headbolts

by the way snipe...best place to get headbolts? It is an expensive hobby, getting more expensive by the minute with gas, so I'm always looking for a way to save a few bucks!

 

[seadoosnipe]

Oh, I thought you might ask...

That would be my "secret" little place. I keep all the good deals tucked away for me..........:rofl:
You can find the rebuild kits at SBT. As for the head bolts...That's another story. But you can probably get those at Babbitts.
The bolts for the 951, P/N 290841708 are about $9.97 and the studs P/N 290640232 are about $12.40 and those are the M10's......the 787 bolts are P/N 290841998 and are $5.40, those are the M8's. Anything else I can do for ya, just holler!......

 

[ALittleNauti]

1998 Speedster hesitation

Forum, thanls for all the useful info, I have learned a lot. My speedster also has a similar hesitation but, it goes away when the engines get warm. Should I be cleaning the RAVE valves? However, I have a secondary problem when the fuel tank gets to 1/2 full or less, the motor RPM's on both motors bounce from 6800 to 4000, and back like it is bumping against a governer. Any idea?